xml.html revision fc263f1fcf09cced050c10e4492e722dbfcfed55
1<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" 2 "http://www.w3.org/TR/html4/loose.dtd"> 3<html> 4<head> 5 <title>The XML C parser and toolkit of Gnome</title> 6 <meta name="GENERATOR" content="amaya 5.1"> 7 <meta http-equiv="Content-Type" content="text/html"> 8</head> 9 10<body bgcolor="#ffffff"> 11<h1 align="center">The XML C parser and toolkit of Gnome</h1> 12 13<h1>Note: this is the flat content of the <a href="index.html">web 14site</a></h1> 15 16<h1 style="text-align: center">libxml, a.k.a. gnome-xml</h1> 17 18<p></p> 19 20<p 21style="text-align: right; font-style: italic; font-size: 10pt">"Programming 22with libxml2 is like the thrilling embrace of an exotic stranger." <a 23href="http://diveintomark.org/archives/2004/02/18/libxml2">Mark 24Pilgrim</a></p> 25 26<p>Libxml2 is the XML C parser and toolkit developed for the Gnome project 27(but usable outside of the Gnome platform), it is free software available 28under the <a href="http://www.opensource.org/licenses/mit-license.html">MIT 29License</a>. XML itself is a metalanguage to design markup languages, i.e. 30text language where semantic and structure are added to the content using 31extra "markup" information enclosed between angle brackets. HTML is the most 32well-known markup language. Though the library is written in C <a 33href="python.html">a variety of language bindings</a> make it available in 34other environments.</p> 35 36<p>Libxml2 is known to be very portable, the library should build and work 37without serious troubles on a variety of systems (Linux, Unix, Windows, 38CygWin, MacOS, MacOS X, RISC Os, OS/2, VMS, QNX, MVS, ...)</p> 39 40<p>Libxml2 implements a number of existing standards related to markup 41languages:</p> 42<ul> 43 <li>the XML standard: <a 44 href="http://www.w3.org/TR/REC-xml">http://www.w3.org/TR/REC-xml</a></li> 45 <li>Namespaces in XML: <a 46 href="http://www.w3.org/TR/REC-xml-names/">http://www.w3.org/TR/REC-xml-names/</a></li> 47 <li>XML Base: <a 48 href="http://www.w3.org/TR/xmlbase/">http://www.w3.org/TR/xmlbase/</a></li> 49 <li><a href="http://www.cis.ohio-state.edu/rfc/rfc2396.txt">RFC 2396</a> : 50 Uniform Resource Identifiers <a 51 href="http://www.ietf.org/rfc/rfc2396.txt">http://www.ietf.org/rfc/rfc2396.txt</a></li> 52 <li>XML Path Language (XPath) 1.0: <a 53 href="http://www.w3.org/TR/xpath">http://www.w3.org/TR/xpath</a></li> 54 <li>HTML4 parser: <a 55 href="http://www.w3.org/TR/html401/">http://www.w3.org/TR/html401/</a></li> 56 <li>XML Pointer Language (XPointer) Version 1.0: <a 57 href="http://www.w3.org/TR/xptr">http://www.w3.org/TR/xptr</a></li> 58 <li>XML Inclusions (XInclude) Version 1.0: <a 59 href="http://www.w3.org/TR/xinclude/">http://www.w3.org/TR/xinclude/</a></li> 60 <li>ISO-8859-x encodings, as well as <a 61 href="http://www.cis.ohio-state.edu/rfc/rfc2044.txt">rfc2044</a> [UTF-8] 62 and <a href="http://www.cis.ohio-state.edu/rfc/rfc2781.txt">rfc2781</a> 63 [UTF-16] Unicode encodings, and more if using iconv support</li> 64 <li>part of SGML Open Technical Resolution TR9401:1997</li> 65 <li>XML Catalogs Working Draft 06 August 2001: <a 66 href="http://www.oasis-open.org/committees/entity/spec-2001-08-06.html">http://www.oasis-open.org/committees/entity/spec-2001-08-06.html</a></li> 67 <li>Canonical XML Version 1.0: <a 68 href="http://www.w3.org/TR/xml-c14n">http://www.w3.org/TR/xml-c14n</a> 69 and the Exclusive XML Canonicalization CR draft <a 70 href="http://www.w3.org/TR/xml-exc-c14n">http://www.w3.org/TR/xml-exc-c14n</a></li> 71 <li>Relax NG, ISO/IEC 19757-2:2003, <a 72 href="http://www.oasis-open.org/committees/relax-ng/spec-20011203.html">http://www.oasis-open.org/committees/relax-ng/spec-20011203.html</a></li> 73 <li>W3C XML Schemas Part 2: Datatypes <a 74 href="http://www.w3.org/TR/2001/REC-xmlschema-2-20010502/">REC 02 May 75 2001</a></li> 76 <li>W3C <a href="http://www.w3.org/TR/xml-id/">xml:id</a> Working Draft 7 77 April 2004</li> 78</ul> 79 80<p>In most cases libxml2 tries to implement the specifications in a 81relatively strictly compliant way. As of release 2.4.16, libxml2 passed all 821800+ tests from the <a 83href="http://www.oasis-open.org/committees/xml-conformance/">OASIS XML Tests 84Suite</a>.</p> 85 86<p>To some extent libxml2 provides support for the following additional 87specifications but doesn't claim to implement them completely:</p> 88<ul> 89 <li>Document Object Model (DOM) <a 90 href="http://www.w3.org/TR/DOM-Level-2-Core/">http://www.w3.org/TR/DOM-Level-2-Core/</a> 91 the document model, but it doesn't implement the API itself, gdome2 does 92 this on top of libxml2</li> 93 <li><a href="http://www.cis.ohio-state.edu/rfc/rfc959.txt">RFC 959</a> : 94 libxml2 implements a basic FTP client code</li> 95 <li><a href="http://www.cis.ohio-state.edu/rfc/rfc1945.txt">RFC 1945</a> : 96 HTTP/1.0, again a basic HTTP client code</li> 97 <li>SAX: a SAX2 like interface and a minimal SAX1 implementation compatible 98 with early expat versions</li> 99</ul> 100 101<p>A partial implementation of <a 102href="http://www.w3.org/TR/2001/REC-xmlschema-1-20010502/">XML Schemas Part 1031: Structure</a> is being worked on but it would be far too early to make any 104conformance statement about it at the moment.</p> 105 106<p>Separate documents:</p> 107<ul> 108 <li><a href="http://xmlsoft.org/XSLT/">the libxslt page</a> providing an 109 implementation of XSLT 1.0 and common extensions like EXSLT for 110 libxml2</li> 111 <li><a href="http://www.cs.unibo.it/~casarini/gdome2/">the gdome2 page</a> 112 : a standard DOM2 implementation for libxml2</li> 113 <li><a href="http://www.aleksey.com/xmlsec/">the XMLSec page</a>: an 114 implementation of <a href="http://www.w3.org/TR/xmldsig-core/">W3C XML 115 Digital Signature</a> for libxml2</li> 116 <li>also check the related links section below for more related and active 117 projects.</li> 118</ul> 119<!----------------<p>Results of the <a 120href="http://xmlbench.sourceforge.net/results/benchmark/index.html">xmlbench 121benchmark</a> on sourceforge February 2004 (smaller is better):</p> 122 123<p align="center"><img src="benchmark.png" 124alt="benchmark results for Expat Xerces libxml2 Oracle and Sun toolkits"></p> 125--------------> 126 127 128<p>Logo designed by <a href="mailto:liyanage@access.ch">Marc Liyanage</a>.</p> 129 130<h2><a name="Introducti">Introduction</a></h2> 131 132<p>This document describes libxml, the <a 133href="http://www.w3.org/XML/">XML</a> C parser and toolkit developed for the 134<a href="http://www.gnome.org/">Gnome</a> project. <a 135href="http://www.w3.org/XML/">XML is a standard</a> for building tag-based 136structured documents/data.</p> 137 138<p>Here are some key points about libxml:</p> 139<ul> 140 <li>Libxml2 exports Push (progressive) and Pull (blocking) type parser 141 interfaces for both XML and HTML.</li> 142 <li>Libxml2 can do DTD validation at parse time, using a parsed document 143 instance, or with an arbitrary DTD.</li> 144 <li>Libxml2 includes complete <a 145 href="http://www.w3.org/TR/xpath">XPath</a>, <a 146 href="http://www.w3.org/TR/xptr">XPointer</a> and <a 147 href="http://www.w3.org/TR/xinclude">XInclude</a> implementations.</li> 148 <li>It is written in plain C, making as few assumptions as possible, and 149 sticking closely to ANSI C/POSIX for easy embedding. Works on 150 Linux/Unix/Windows, ported to a number of other platforms.</li> 151 <li>Basic support for HTTP and FTP client allowing applications to fetch 152 remote resources.</li> 153 <li>The design is modular, most of the extensions can be compiled out.</li> 154 <li>The internal document representation is as close as possible to the <a 155 href="http://www.w3.org/DOM/">DOM</a> interfaces.</li> 156 <li>Libxml2 also has a <a 157 href="http://www.megginson.com/SAX/index.html">SAX like interface</a>; 158 the interface is designed to be compatible with <a 159 href="http://www.jclark.com/xml/expat.html">Expat</a>.</li> 160 <li>This library is released under the <a 161 href="http://www.opensource.org/licenses/mit-license.html">MIT 162 License</a>. See the Copyright file in the distribution for the precise 163 wording.</li> 164</ul> 165 166<p>Warning: unless you are forced to because your application links with a 167Gnome-1.X library requiring it, <strong><span 168style="background-color: #FF0000">Do Not Use libxml1</span></strong>, use 169libxml2</p> 170 171<h2><a name="FAQ">FAQ</a></h2> 172 173<p>Table of Contents:</p> 174<ul> 175 <li><a href="FAQ.html#License">License(s)</a></li> 176 <li><a href="FAQ.html#Installati">Installation</a></li> 177 <li><a href="FAQ.html#Compilatio">Compilation</a></li> 178 <li><a href="FAQ.html#Developer">Developer corner</a></li> 179</ul> 180 181<h3><a name="License">License</a>(s)</h3> 182<ol> 183 <li><em>Licensing Terms for libxml</em> 184 <p>libxml2 is released under the <a 185 href="http://www.opensource.org/licenses/mit-license.html">MIT 186 License</a>; see the file Copyright in the distribution for the precise 187 wording</p> 188 </li> 189 <li><em>Can I embed libxml2 in a proprietary application ?</em> 190 <p>Yes. The MIT License allows you to keep proprietary the changes you 191 made to libxml, but it would be graceful to send-back bug fixes and 192 improvements as patches for possible incorporation in the main 193 development tree.</p> 194 </li> 195</ol> 196 197<h3><a name="Installati">Installation</a></h3> 198<ol> 199 <li><strong><span style="background-color: #FF0000">Do Not Use 200 libxml1</span></strong>, use libxml2</li> 201 <li><em>Where can I get libxml</em> ? 202 <p>The original distribution comes from <a 203 href="ftp://rpmfind.net/pub/libxml/">rpmfind.net</a> or <a 204 href="ftp://ftp.gnome.org/pub/GNOME/sources/libxml2/2.6/">gnome.org</a></p> 205 <p>Most Linux and BSD distributions include libxml, this is probably the 206 safer way for end-users to use libxml.</p> 207 <p>David Doolin provides precompiled Windows versions at <a 208 href="http://www.ce.berkeley.edu/~doolin/code/libxmlwin32/ ">http://www.ce.berkeley.edu/~doolin/code/libxmlwin32/</a></p> 209 </li> 210 <li><em>I see libxml and libxml2 releases, which one should I install ?</em> 211 <ul> 212 <li>If you are not constrained by backward compatibility issues with 213 existing applications, install libxml2 only</li> 214 <li>If you are not doing development, you can safely install both. 215 Usually the packages <a 216 href="http://rpmfind.net/linux/RPM/libxml.html">libxml</a> and <a 217 href="http://rpmfind.net/linux/RPM/libxml2.html">libxml2</a> are 218 compatible (this is not the case for development packages).</li> 219 <li>If you are a developer and your system provides separate packaging 220 for shared libraries and the development components, it is possible 221 to install libxml and libxml2, and also <a 222 href="http://rpmfind.net/linux/RPM/libxml-devel.html">libxml-devel</a> 223 and <a 224 href="http://rpmfind.net/linux/RPM/libxml2-devel.html">libxml2-devel</a> 225 too for libxml2 >= 2.3.0</li> 226 <li>If you are developing a new application, please develop against 227 libxml2(-devel)</li> 228 </ul> 229 </li> 230 <li><em>I can't install the libxml package, it conflicts with libxml0</em> 231 <p>You probably have an old libxml0 package used to provide the shared 232 library for libxml.so.0, you can probably safely remove it. The libxml 233 packages provided on <a 234 href="ftp://rpmfind.net/pub/libxml/">rpmfind.net</a> provide 235 libxml.so.0</p> 236 </li> 237 <li><em>I can't install the libxml(2) RPM package due to failed 238 dependencies</em> 239 <p>The most generic solution is to re-fetch the latest src.rpm , and 240 rebuild it locally with</p> 241 <p><code>rpm --rebuild libxml(2)-xxx.src.rpm</code>.</p> 242 <p>If everything goes well it will generate two binary rpm packages (one 243 providing the shared libs and xmllint, and the other one, the -devel 244 package, providing includes, static libraries and scripts needed to build 245 applications with libxml(2)) that you can install locally.</p> 246 </li> 247</ol> 248 249<h3><a name="Compilatio">Compilation</a></h3> 250<ol> 251 <li><em>What is the process to compile libxml2 ?</em> 252 <p>As most UNIX libraries libxml2 follows the "standard":</p> 253 <p><code>gunzip -c xxx.tar.gz | tar xvf -</code></p> 254 <p><code>cd libxml-xxxx</code></p> 255 <p><code>/configure --help</code></p> 256 <p>to see the options, then the compilation/installation proper</p> 257 <p><code>/configure [possible options]</code></p> 258 <p><code>make</code></p> 259 <p><code>make install</code></p> 260 <p>At that point you may have to rerun ldconfig or a similar utility to 261 update your list of installed shared libs.</p> 262 </li> 263 <li><em>What other libraries are needed to compile/install libxml2 ?</em> 264 <p>Libxml2 does not require any other library, the normal C ANSI API 265 should be sufficient (please report any violation to this rule you may 266 find).</p> 267 <p>However if found at configuration time libxml2 will detect and use the 268 following libs:</p> 269 <ul> 270 <li><a href="http://www.info-zip.org/pub/infozip/zlib/">libz</a> : a 271 highly portable and available widely compression library.</li> 272 <li>iconv: a powerful character encoding conversion library. It is 273 included by default in recent glibc libraries, so it doesn't need to 274 be installed specifically on Linux. It now seems a <a 275 href="http://www.opennc.org/onlinepubs/7908799/xsh/iconv.html">part 276 of the official UNIX</a> specification. Here is one <a 277 href="http://www.gnu.org/software/libiconv/">implementation of the 278 library</a> which source can be found <a 279 href="ftp://ftp.ilog.fr/pub/Users/haible/gnu/">here</a>.</li> 280 </ul> 281 </li> 282 <li><em>Make check fails on some platforms</em> 283 <p>Sometimes the regression tests' results don't completely match the 284 value produced by the parser, and the makefile uses diff to print the 285 delta. On some platforms the diff return breaks the compilation process; 286 if the diff is small this is probably not a serious problem.</p> 287 <p>Sometimes (especially on Solaris) make checks fail due to limitations 288 in make. Try using GNU-make instead.</p> 289 </li> 290 <li><em>I use the CVS version and there is no configure script</em> 291 <p>The configure script (and other Makefiles) are generated. Use the 292 autogen.sh script to regenerate the configure script and Makefiles, 293 like:</p> 294 <p><code>/autogen.sh --prefix=/usr --disable-shared</code></p> 295 </li> 296 <li><em>I have troubles when running make tests with gcc-3.0</em> 297 <p>It seems the initial release of gcc-3.0 has a problem with the 298 optimizer which miscompiles the URI module. Please use another 299 compiler.</p> 300 </li> 301</ol> 302 303<h3><a name="Developer">Developer</a> corner</h3> 304<ol> 305 <li><em>Troubles compiling or linking programs using libxml2</em> 306 <p>Usually the problem comes from the fact that the compiler doesn't get 307 the right compilation or linking flags. There is a small shell script 308 <code>xml2-config</code> which is installed as part of libxml2 usual 309 install process which provides those flags. Use</p> 310 <p><code>xml2-config --cflags</code></p> 311 <p>to get the compilation flags and</p> 312 <p><code>xml2-config --libs</code></p> 313 <p>to get the linker flags. Usually this is done directly from the 314 Makefile as:</p> 315 <p><code>CFLAGS=`xml2-config --cflags`</code></p> 316 <p><code>LIBS=`xml2-config --libs`</code></p> 317 </li> 318 <li><em>xmlDocDump() generates output on one line.</em> 319 <p>Libxml2 will not <strong>invent</strong> spaces in the content of a 320 document since <strong>all spaces in the content of a document are 321 significant</strong>. If you build a tree from the API and want 322 indentation:</p> 323 <ol> 324 <li>the correct way is to generate those yourself too.</li> 325 <li>the dangerous way is to ask libxml2 to add those blanks to your 326 content <strong>modifying the content of your document in the 327 process</strong>. The result may not be what you expect. There is 328 <strong>NO</strong> way to guarantee that such a modification won't 329 affect other parts of the content of your document. See <a 330 href="http://xmlsoft.org/html/libxml-parser.html#xmlKeepBlanksDefault">xmlKeepBlanksDefault 331 ()</a> and <a 332 href="http://xmlsoft.org/html/libxml-tree.html#xmlSaveFormatFile">xmlSaveFormatFile 333 ()</a></li> 334 </ol> 335 </li> 336 <li>Extra nodes in the document: 337 <p><em>For a XML file as below:</em></p> 338 <pre><?xml version="1.0"?> 339<PLAN xmlns="http://www.argus.ca/autotest/1.0/"> 340<NODE CommFlag="0"/> 341<NODE CommFlag="1"/> 342</PLAN></pre> 343 <p><em>after parsing it with the function 344 pxmlDoc=xmlParseFile(...);</em></p> 345 <p><em>I want to the get the content of the first node (node with the 346 CommFlag="0")</em></p> 347 <p><em>so I did it as following;</em></p> 348 <pre>xmlNodePtr pnode; 349pnode=pxmlDoc->children->children;</pre> 350 <p><em>but it does not work. If I change it to</em></p> 351 <pre>pnode=pxmlDoc->children->children->next;</pre> 352 <p><em>then it works. Can someone explain it to me.</em></p> 353 <p></p> 354 <p>In XML all characters in the content of the document are significant 355 <strong>including blanks and formatting line breaks</strong>.</p> 356 <p>The extra nodes you are wondering about are just that, text nodes with 357 the formatting spaces which are part of the document but that people tend 358 to forget. There is a function <a 359 href="http://xmlsoft.org/html/libxml-parser.html">xmlKeepBlanksDefault 360 ()</a> to remove those at parse time, but that's an heuristic, and its 361 use should be limited to cases where you are certain there is no 362 mixed-content in the document.</p> 363 </li> 364 <li><em>I get compilation errors of existing code like when accessing 365 <strong>root</strong> or <strong>child fields</strong> of nodes.</em> 366 <p>You are compiling code developed for libxml version 1 and using a 367 libxml2 development environment. Either switch back to libxml v1 devel or 368 even better fix the code to compile with libxml2 (or both) by <a 369 href="upgrade.html">following the instructions</a>.</p> 370 </li> 371 <li><em>I get compilation errors about non existing 372 <strong>xmlRootNode</strong> or <strong>xmlChildrenNode</strong> 373 fields.</em> 374 <p>The source code you are using has been <a 375 href="upgrade.html">upgraded</a> to be able to compile with both libxml 376 and libxml2, but you need to install a more recent version: 377 libxml(-devel) >= 1.8.8 or libxml2(-devel) >= 2.1.0</p> 378 </li> 379 <li><em>XPath implementation looks seriously broken</em> 380 <p>XPath implementation prior to 2.3.0 was really incomplete. Upgrade to 381 a recent version, there are no known bugs in the current version.</p> 382 </li> 383 <li><em>The example provided in the web page does not compile.</em> 384 <p>It's hard to maintain the documentation in sync with the code 385 <grin/> ...</p> 386 <p>Check the previous points 1/ and 2/ raised before, and please send 387 patches.</p> 388 </li> 389 <li><em>Where can I get more examples and information than provided on the 390 web page?</em> 391 <p>Ideally a libxml2 book would be nice. I have no such plan ... But you 392 can:</p> 393 <ul> 394 <li>check more deeply the <a href="html/libxml-lib.html">existing 395 generated doc</a></li> 396 <li>have a look at <a href="examples/index.html">the set of 397 examples</a>.</li> 398 <li>look for examples of use for libxml2 function using the Gnome code. 399 For example the following will query the full Gnome CVS base for the 400 use of the <strong>xmlAddChild()</strong> function: 401 <p><a 402 href="http://cvs.gnome.org/lxr/search?string=xmlAddChild">http://cvs.gnome.org/lxr/search?string=xmlAddChild</a></p> 403 <p>This may be slow, a large hardware donation to the gnome project 404 could cure this :-)</p> 405 </li> 406 <li><a 407 href="http://cvs.gnome.org/bonsai/rview.cgi?cvsroot=/cvs/gnome&dir=gnome-xml">Browse 408 the libxml2 source</a> , I try to write code as clean and documented 409 as possible, so looking at it may be helpful. In particular the code 410 of xmllint.c and of the various testXXX.c test programs should 411 provide good examples of how to do things with the library.</li> 412 </ul> 413 </li> 414 <li>What about C++ ? 415 <p>libxml2 is written in pure C in order to allow easy reuse on a number 416 of platforms, including embedded systems. I don't intend to convert to 417 C++.</p> 418 <p>There is however a C++ wrapper which may fulfill your needs:</p> 419 <ul> 420 <li>by Ari Johnson <ari@btigate.com>: 421 <p>Website: <a 422 href="http://libxmlplusplus.sourceforge.net/">http://libxmlplusplus.sourceforge.net/</a></p> 423 <p>Download: <a 424 href="http://sourceforge.net/project/showfiles.php?group_id=12999">http://sourceforge.net/project/showfiles.php?group_id=12999</a></p> 425 </li> 426 <!-- Website is currently unavailable as of 2003-08-02 427 <li>by Peter Jones <pjones@pmade.org> 428 <p>Website: <a 429 href="http://pmade.org/pjones/software/xmlwrapp/">http://pmade.org/pjones/software/xmlwrapp/</a></p> 430 </li> 431 --> 432 </ul> 433 </li> 434 <li>How to validate a document a posteriori ? 435 <p>It is possible to validate documents which had not been validated at 436 initial parsing time or documents which have been built from scratch 437 using the API. Use the <a 438 href="http://xmlsoft.org/html/libxml-valid.html#xmlValidateDtd">xmlValidateDtd()</a> 439 function. It is also possible to simply add a DTD to an existing 440 document:</p> 441 <pre>xmlDocPtr doc; /* your existing document */ 442xmlDtdPtr dtd = xmlParseDTD(NULL, filename_of_dtd); /* parse the DTD */ 443 444 dtd->name = xmlStrDup((xmlChar*)"root_name"); /* use the given root */ 445 446 doc->intSubset = dtd; 447 if (doc->children == NULL) xmlAddChild((xmlNodePtr)doc, (xmlNodePtr)dtd); 448 else xmlAddPrevSibling(doc->children, (xmlNodePtr)dtd); 449 </pre> 450 </li> 451 <li>So what is this funky "xmlChar" used all the time? 452 <p>It is a null terminated sequence of utf-8 characters. And only utf-8! 453 You need to convert strings encoded in different ways to utf-8 before 454 passing them to the API. This can be accomplished with the iconv library 455 for instance.</p> 456 </li> 457 <li>etc ...</li> 458</ol> 459 460<p></p> 461 462<h2><a name="Documentat">Developer Menu</a></h2> 463 464<p>There are several on-line resources related to using libxml:</p> 465<ol> 466 <li>Use the <a href="search.php">search engine</a> to look up 467 information.</li> 468 <li>Check the <a href="FAQ.html">FAQ.</a></li> 469 <li>Check the <a href="http://xmlsoft.org/html/libxml-lib.html">extensive 470 documentation</a> automatically extracted from code comments.</li> 471 <li>Look at the documentation about <a href="encoding.html">libxml 472 internationalization support</a>.</li> 473 <li>This page provides a global overview and <a href="example.html">some 474 examples</a> on how to use libxml.</li> 475 <li><a href="examples/index.html">Code examples</a></li> 476 <li>John Fleck's libxml2 tutorial: <a href="tutorial/index.html">html</a> 477 or <a href="tutorial/xmltutorial.pdf">pdf</a>.</li> 478 <li>If you need to parse large files, check the <a 479 href="xmlreader.html">xmlReader</a> API tutorial</li> 480 <li><a href="mailto:james@daa.com.au">James Henstridge</a> wrote <a 481 href="http://www.daa.com.au/~james/gnome/xml-sax/xml-sax.html">some nice 482 documentation</a> explaining how to use the libxml SAX interface.</li> 483 <li>George Lebl wrote <a 484 href="http://www-106.ibm.com/developerworks/library/l-gnome3/">an article 485 for IBM developerWorks</a> about using libxml.</li> 486 <li>Check <a href="http://cvs.gnome.org/lxr/source/gnome-xml/TODO">the TODO 487 file</a>.</li> 488 <li>Read the <a href="upgrade.html">1.x to 2.x upgrade path</a> 489 description. If you are starting a new project using libxml you should 490 really use the 2.x version.</li> 491 <li>And don't forget to look at the <a 492 href="http://mail.gnome.org/archives/xml/">mailing-list archive</a>.</li> 493</ol> 494 495<h2><a name="Reporting">Reporting bugs and getting help</a></h2> 496 497<p>Well, bugs or missing features are always possible, and I will make a 498point of fixing them in a timely fashion. The best way to report a bug is to 499use the <a href="http://bugzilla.gnome.org/buglist.cgi?product=libxml2">Gnome 500bug tracking database</a> (make sure to use the "libxml2" module name). I 501look at reports there regularly and it's good to have a reminder when a bug 502is still open. Be sure to specify that the bug is for the package libxml2.</p> 503 504<p>For small problems you can try to get help on IRC, the #xml channel on 505irc.gnome.org (port 6667) usually have a few person subscribed which may help 506(but there is no garantee and if a real issue is raised it should go on the 507mailing-list for archival).</p> 508 509<p>There is also a mailing-list <a 510href="mailto:xml@gnome.org">xml@gnome.org</a> for libxml, with an <a 511href="http://mail.gnome.org/archives/xml/">on-line archive</a> (<a 512href="http://xmlsoft.org/messages">old</a>). To subscribe to this list, 513please visit the <a 514href="http://mail.gnome.org/mailman/listinfo/xml">associated Web</a> page and 515follow the instructions. <strong>Do not send code, I won't debug it</strong> 516(but patches are really appreciated!).</p> 517 518<p>Please note that with the current amount of virus and SPAM, sending mail 519to the list without being subscribed won't work. There is *far too many 520bounces* (in the order of a thousand a day !) I cannot approve them manually 521anymore. If your mail to the list bounced waiting for administrator approval, 522it is LOST ! Repost it and fix the problem triggering the error.</p> 523 524<p>Check the following <strong><span style="color: #FF0000">before 525posting</span></strong>:</p> 526<ul> 527 <li>Read the <a href="FAQ.html">FAQ</a> and <a href="search.php">use the 528 search engine</a> to get information related to your problem.</li> 529 <li>Make sure you are <a href="ftp://xmlsoft.org/">using a recent 530 version</a>, and that the problem still shows up in a recent version.</li> 531 <li>Check the <a href="http://mail.gnome.org/archives/xml/">list 532 archives</a> to see if the problem was reported already. In this case 533 there is probably a fix available, similarly check the <a 534 href="http://bugzilla.gnome.org/buglist.cgi?product=libxml2">registered 535 open bugs</a>.</li> 536 <li>Make sure you can reproduce the bug with xmllint or one of the test 537 programs found in source in the distribution.</li> 538 <li>Please send the command showing the error as well as the input (as an 539 attachment)</li> 540</ul> 541 542<p>Then send the bug with associated information to reproduce it to the <a 543href="mailto:xml@gnome.org">xml@gnome.org</a> list; if it's really libxml 544related I will approve it. Please do not send mail to me directly, it makes 545things really hard to track and in some cases I am not the best person to 546answer a given question, ask on the list.</p> 547 548<p>To <span style="color: #E50000">be really clear about support</span>:</p> 549<ul> 550 <li>Support or help <span style="color: #E50000">requests MUST be sent to 551 the list or on bugzilla</span> in case of problems, so that the Question 552 and Answers can be shared publicly. Failing to do so carries the implicit 553 message "I want free support but I don't want to share the benefits with 554 others" and is not welcome. I will automatically Carbon-Copy the 555 xml@gnome.org mailing list for any technical reply made about libxml2 or 556 libxslt.</li> 557 <li>There is <span style="color: #E50000">no garantee of support</span>, if 558 your question remains unanswered after a week, repost it, making sure you 559 gave all the detail needed and the information requested.</li> 560 <li>Failing to provide information as requested or double checking first 561 for prior feedback also carries the implicit message "the time of the 562 library maintainers is less valuable than my time" and might not be 563 welcome.</li> 564</ul> 565 566<p>Of course, bugs reported with a suggested patch for fixing them will 567probably be processed faster than those without.</p> 568 569<p>If you're looking for help, a quick look at <a 570href="http://mail.gnome.org/archives/xml/">the list archive</a> may actually 571provide the answer. I usually send source samples when answering libxml2 572usage questions. The <a 573href="http://xmlsoft.org/html/book1.html">auto-generated documentation</a> is 574not as polished as I would like (i need to learn more about DocBook), but 575it's a good starting point.</p> 576 577<h2><a name="help">How to help</a></h2> 578 579<p>You can help the project in various ways, the best thing to do first is to 580subscribe to the mailing-list as explained before, check the <a 581href="http://mail.gnome.org/archives/xml/">archives </a>and the <a 582href="http://bugzilla.gnome.org/buglist.cgi?product=libxml2">Gnome bug 583database</a>:</p> 584<ol> 585 <li>Provide patches when you find problems.</li> 586 <li>Provide the diffs when you port libxml2 to a new platform. They may not 587 be integrated in all cases but help pinpointing portability problems 588 and</li> 589 <li>Provide documentation fixes (either as patches to the code comments or 590 as HTML diffs).</li> 591 <li>Provide new documentations pieces (translations, examples, etc 592 ...).</li> 593 <li>Check the TODO file and try to close one of the items.</li> 594 <li>Take one of the points raised in the archive or the bug database and 595 provide a fix. <a href="mailto:daniel@veillard.com">Get in touch with me 596 </a>before to avoid synchronization problems and check that the suggested 597 fix will fit in nicely :-)</li> 598</ol> 599 600<h2><a name="Downloads">Downloads</a></h2> 601 602<p>The latest versions of libxml2 can be found on the <a 603href="ftp://xmlsoft.org/">xmlsoft.org</a> server ( <a 604href="http://xmlsoft.org/sources/">HTTP</a>, <a 605href="ftp://xmlsoft.org/">FTP</a> and rsync are available), there is also 606mirrors (<a href="ftp://speakeasy.rpmfind.net/pub/libxml/">Seattle</a>, <a 607href="ftp://fr.rpmfind.net/pub/libxml/">France</a>) or on the <a 608href="ftp://ftp.gnome.org/pub/GNOME/MIRRORS.html">Gnome FTP server</a> as <a 609href="ftp://ftp.gnome.org/pub/GNOME/sources/libxml2/2.6/">source archive</a> 610, Antonin Sprinzl also provide <a href="ftp://gd.tuwien.ac.at/pub/libxml/">a 611mirror in Austria</a>. (NOTE that you need both the <a 612href="http://rpmfind.net/linux/RPM/libxml2.html">libxml(2)</a> and <a 613href="http://rpmfind.net/linux/RPM/libxml2-devel.html">libxml(2)-devel</a> 614packages installed to compile applications using libxml.)</p> 615 616<p>You can find all the history of libxml(2) and libxslt releases in the <a 617href="http://xmlsoft.org/sources/old/">old</a> directory. The precompiled 618Windows binaries made by Igor Zlatovic are available in the <a 619href="http://xmlsoft.org/sources/win32/">win32</a> directory.</p> 620 621<p>Binary ports:</p> 622<ul> 623 <li>Red Hat RPMs for i386 are available directly on <a 624 href="ftp://xmlsoft.org/">xmlsoft.org</a>, the source RPM will compile on 625 any architecture supported by Red Hat.</li> 626 <li><a href="mailto:igor@zlatkovic.com">Igor Zlatkovic</a> is now the 627 maintainer of the Windows port, <a 628 href="http://www.zlatkovic.com/projects/libxml/index.html">he provides 629 binaries</a>.</li> 630 <li><a href="mailto:Gary.Pennington@sun.com">Gary Pennington</a> provides 631 <a href="http://garypennington.net/libxml2/">Solaris binaries</a>.</li> 632 <li><a href="mailto:Steve.Ball@zveno.com">Steve Ball</a> provides <a 633 href="http://www.zveno.com/open_source/libxml2xslt.html">Mac Os X 634 binaries</a>.</li> 635 <li>The HP-UX porting center provides <a 636 href="http://hpux.connect.org.uk/hppd/hpux/Gnome/">HP-UX binaries</a></li> 637</ul> 638 639<p>If you know other supported binary ports, please <a 640href="http://veillard.com/">contact me</a>.</p> 641 642<p><a name="Snapshot">Snapshot:</a></p> 643<ul> 644 <li>Code from the W3C cvs base libxml2 module, updated hourly <a 645 href="ftp://xmlsoft.org/libxml2-cvs-snapshot.tar.gz">libxml2-cvs-snapshot.tar.gz</a>.</li> 646 <li>Docs, content of the web site, the list archive included <a 647 href="ftp://xmlsoft.org/libxml-docs.tar.gz">libxml-docs.tar.gz</a>.</li> 648</ul> 649 650<p><a name="Contribs">Contributions:</a></p> 651 652<p>I do accept external contributions, especially if compiling on another 653platform, get in touch with the list to upload the package, wrappers for 654various languages have been provided, and can be found in the <a 655href="python.html">bindings section</a></p> 656 657<p>Libxml2 is also available from CVS:</p> 658<ul> 659 <li><p>The <a href="http://cvs.gnome.org/viewcvs/libxml2/">Gnome CVS 660 base</a>. Check the <a 661 href="http://developer.gnome.org/tools/cvs.html">Gnome CVS Tools</a> 662 page; the CVS module is <b>libxml2</b>.</p> 663 </li> 664 <li>The <strong>libxslt</strong> module is also present there</li> 665</ul> 666 667<h2><a name="News">News</a></h2> 668 669<p>Items not finished and worked on, get in touch with the list if you want 670to help those</p> 671<ul> 672 <li>More testing on RelaxNG</li> 673 <li>Finishing up <a href="http://www.w3.org/TR/xmlschema-1/">XML 674 Schemas</a></li> 675</ul> 676 677<p>The <a href="ChangeLog.html">change log</a> describes the recents commits 678to the <a href="http://cvs.gnome.org/viewcvs/libxml2/">CVS</a> code base.</p> 679 680<p>There is the list of public releases:</p> 681 682<h3>2.6.12: Aug 22 2004</h3> 683<ul> 684 <li>build fixes: fix --with-minimum, elfgcchack.h fixes (Peter 685 Breitenlohner), perl path lookup (William), diff on Solaris (Albert 686 Chin), some 64bits cleanups.</li> 687 <li>Python: avoid a warning with 2.3 (William Brack), tab and space mixes 688 (William), wrapper generator fixes (William), Cygwin support (Gerrit P. 689 Haase), node wrapper fix (Marc-Antoine Parent), XML Schemas support 690 (Torkel Lyng)</li> 691 <li>Schemas: a lot of bug fixes and improvements from Kasimier Buchcik</li> 692 <li>fixes: RVT fixes (William), XPath context resets bug (William), memory 693 debug (Steve Hay), catalog white space handling (Peter Breitenlohner), 694 xmlReader state after attribute reading (William), structured error 695 handler (William), XInclude generated xml:base fixup (William), Windows 696 memory reallocation problem (Steve Hay), Out of Memory conditions 697 handling (William and Olivier Andrieu), htmlNewDoc() charset bug, 698 htmlReadMemory init (William), a posteriori validation DTD base 699 (William), notations serialization missing, xmlGetNodePath (Dodji), 700 xmlCheckUTF8 (Diego Tartara), missing line numbers on entity 701 (William)</li> 702 <li>improvements: DocBook catalog build scrip (William), xmlcatalog tool 703 (Albert Chin), xmllint --c14n option, no_proxy environment (Mike Hommey), 704 xmlParseInNodeContext() addition, extend xmllint --shell, allow XInclude 705 to not generate start/end nodes, extend xmllint --version to include CVS 706 tag (William)</li> 707 <li>documentation: web pages fixes, validity API docs fixes (William) 708 schemas API fix (Eric Haszlakiewicz), xmllint man page (John Fleck)</li> 709</ul> 710 711<h3>2.6.11: July 5 2004</h3> 712<ul> 713 <li>Schemas: a lot of changes and improvements by Kasimier Buchcik for 714 attributes, namespaces and simple types.</li> 715 <li>build fixes: --with-minimum (William Brack), some gcc cleanup 716 (William), --with-thread-alloc (William)</li> 717 <li>portability: Windows binary package change (Igor Zlatkovic), Catalog 718 path on Windows</li> 719 <li>documentation: update to the tutorial (John Fleck), xmllint return code 720 (John Fleck), man pages (Ville Skytta),</li> 721 <li>bug fixes: C14N bug serializing namespaces (Aleksey Sanin), testSAX 722 properly initialize the library (William), empty node set in XPath 723 (William), xmlSchemas errors (William), invalid charref problem pointed 724 by Morus Walter, XInclude xml:base generation (William), Relax-NG bug 725 with div processing (William), XPointer and xml:base problem(William), 726 Reader and entities, xmllint return code for schemas (William), reader 727 streaming problem (Steve Ball), DTD serialization problem (William), 728 libxml.m4 fixes (Mike Hommey), do not provide destructors as methods on 729 Python classes, xmlReader buffer bug, Python bindings memory interfaces 730 improvement (with St�phane Bidoul), Fixed the push parser to be back to 731 synchronous behaviour.</li> 732 <li>improvement: custom per-thread I/O enhancement (Rob Richards), register 733 namespace in debug shell (Stefano Debenedetti), Python based regression 734 test for non-Unix users (William), dynamically increase the number of 735 XPath extension functions in Python and fix a memory leak (Marc-Antoine 736 Parent and William)</li> 737 <li>performance: hack done with Arjan van de Ven to reduce ELF footprint 738 and generated code on Linux, plus use gcc runtime profiling to optimize 739 the code generated in the RPM packages.</li> 740</ul> 741 742<h3>2.6.10: May 17 2004</h3> 743<ul> 744 <li>Web page generated for ChangeLog</li> 745 <li>build fixes: --without-html problems, make check without make all</li> 746 <li>portability: problem with xpath.c on Windows (MSC and Borland), memcmp 747 vs. strncmp on Solaris, XPath tests on Windows (Mark Vakoc), C++ do not 748 use "list" as parameter name, make tests work with Python 1.5 (Ed 749 Davis),</li> 750 <li>improvements: made xmlTextReaderMode public, small buffers resizing 751 (Morten Welinder), add --maxmem option to xmllint, add 752 xmlPopInputCallback() for Matt Sergeant, refactoring of serialization 753 escaping, added escaping customization</li> 754 <li>bugfixes: xsd:extension (Taihei Goi), assorted regexp bugs (William 755 Brack), xmlReader end of stream problem, node deregistration with reader, 756 URI escaping and filemanes, XHTML1 formatting (Nick Wellnhofer), regexp 757 transition reduction (William), various XSD Schemas fixes (Kasimier 758 Buchcik), XInclude fallback problem (William), weird problems with DTD 759 (William), structured error handler callback context (William), reverse 760 xmlEncodeSpecialChars() behaviour back to escaping '"'</li> 761</ul> 762 763<h3>2.6.9: Apr 18 2004</h3> 764<ul> 765 <li>implement xml:id Working Draft, relaxed XPath id() checking</li> 766 <li>bugfixes: xmlCtxtReset (Brent Hendricks), line number and CDATA (Dave 767 Beckett), Relax-NG compilation (William Brack), Regexp patches (with 768 William), xmlUriEscape (Mark Vakoc), a Relax-NG notAllowed problem (with 769 William), Relax-NG name classes compares (William), XInclude duplicate 770 fallback (William), external DTD encoding detection (William), a DTD 771 validation bug (William), xmlReader Close() fix, recusive extention 772 schemas</li> 773 <li>improvements: use xmlRead* APIs in test tools (Mark Vakoc), indenting 774 save optimization, better handle IIS broken HTTP redirect behaviour (Ian 775 Hummel), HTML parser frameset (James Bursa), libxml2-python RPM 776 dependancy, XML Schemas union support (Kasimier Buchcik), warning removal 777 clanup (William), keep ChangeLog compressed when installing from RPMs</li> 778 <li>documentation: examples and xmlDocDumpMemory docs (John Fleck), new 779 example (load, xpath, modify, save), xmlCatalogDump() comments,</li> 780 <li>Windows: Borland C++ builder (Eric Zurcher), work around Microsoft 781 compiler NaN handling bug (Mark Vakoc)</li> 782</ul> 783 784<h3>2.6.8: Mar 23 2004</h3> 785<ul> 786 <li>First step of the cleanup of the serialization code and APIs</li> 787 <li>XML Schemas: mixed content (Adam Dickmeiss), QName handling fixes (Adam 788 Dickmeiss), anyURI for "" (John Belmonte)</li> 789 <li>Python: Canonicalization C14N support added (Anthony Carrico)</li> 790 <li>xmlDocCopyNode() extension (William)</li> 791 <li>Relax-NG: fix when processing XInclude results (William), external 792 reference in interleave (William), missing error on <choice> 793 failure (William), memory leak in schemas datatype facets.</li> 794 <li>xmlWriter: patch for better DTD support (Alfred Mickautsch)</li> 795 <li>bug fixes: xmlXPathLangFunction memory leak (Mike Hommey and William 796 Brack), no ID errors if using HTML_PARSE_NOERROR, xmlcatalog fallbacks to 797 URI on SYSTEM lookup failure, XInclude parse flags inheritance (William), 798 XInclude and XPointer fixes for entities (William), XML parser bug 799 reported by Holger Rauch, nanohttp fd leak (William), regexps char 800 groups '-' handling (William), dictionnary reference counting problems, 801 do not close stderr.</li> 802 <li>performance patches from Petr Pajas</li> 803 <li>Documentation fixes: XML_CATALOG_FILES in man pages (Mike Hommey)</li> 804 <li>compilation and portability fixes: --without-valid, catalog cleanups 805 (Peter Breitenlohner), MingW patch (Roland Schwingel), cross-compilation 806 to Windows (Christophe de Vienne), --with-html-dir fixup (Julio Merino 807 Vidal), Windows build (Eric Zurcher)</li> 808</ul> 809 810<h3>2.6.7: Feb 23 2004</h3> 811<ul> 812 <li>documentation: tutorial updates (John Fleck), benchmark results</li> 813 <li>xmlWriter: updates and fixes (Alfred Mickautsch, Lucas Brasilino)</li> 814 <li>XPath optimization (Petr Pajas)</li> 815 <li>DTD ID handling optimization</li> 816 <li>bugfixes: xpath number with > 19 fractional (William Brack), push 817 mode with unescaped '>' characters, fix xmllint --stream --timing, fix 818 xmllint --memory --stream memory usage, xmlAttrSerializeTxtContent 819 handling NULL, trying to fix Relax-NG/Perl interface.</li> 820 <li>python: 2.3 compatibility, whitespace fixes (Malcolm Tredinnick)</li> 821 <li>Added relaxng option to xmllint --shell</li> 822</ul> 823 824<h3>2.6.6: Feb 12 2004</h3> 825<ul> 826 <li>nanohttp and nanoftp: buffer overflow error on URI parsing (Igor and 827 William) reported by Yuuichi Teranishi</li> 828 <li>bugfixes: make test and path issues, xmlWriter attribute serialization 829 (William Brack), xmlWriter indentation (William), schemas validation 830 (Eric Haszlakiewicz), XInclude dictionnaries issues (William and Oleg 831 Paraschenko), XInclude empty fallback (William), HTML warnings (William), 832 XPointer in XInclude (William), Python namespace serialization, 833 isolat1ToUTF8 bound error (Alfred Mickautsch), output of parameter 834 entities in internal subset (William), internal subset bug in push mode, 835 <xs:all> fix (Alexey Sarytchev)</li> 836 <li>Build: fix for automake-1.8 (Alexander Winston), warnings removal 837 (Philip Ludlam), SOCKLEN_T detection fixes (Daniel Richard), fix 838 --with-minimum configuration.</li> 839 <li>XInclude: allow the 2001 namespace without warning.</li> 840 <li>Documentation: missing example/index.html (John Fleck), version 841 dependancies (John Fleck)</li> 842 <li>reader API: structured error reporting (Steve Ball)</li> 843 <li>Windows compilation: mingw, msys (Mikhail Grushinskiy), function 844 prototype (Cameron Johnson), MSVC6 compiler warnings, _WINSOCKAPI_ 845 patch</li> 846 <li>Parsers: added xmlByteConsumed(ctxt) API to get the byte offest in 847 input.</li> 848</ul> 849 850<h3>2.6.5: Jan 25 2004</h3> 851<ul> 852 <li>Bugfixes: dictionnaries for schemas (William Brack), regexp segfault 853 (William), xs:all problem (William), a number of XPointer bugfixes 854 (William), xmllint error go to stderr, DTD validation problem with 855 namespace, memory leak (William), SAX1 cleanup and minimal options fixes 856 (Mark Vadoc), parser context reset on error (Shaun McCance), XPath union 857 evaluation problem (William) , xmlReallocLoc with NULL (Aleksey Sanin), 858 XML Schemas double free (Steve Ball), XInclude with no href, argument 859 callbacks order for XPath callbacks (Frederic Peters)</li> 860 <li>Documentation: python scripts (William Brack), xslt stylesheets (John 861 Fleck), doc (Sven Zimmerman), I/O example.</li> 862 <li>Python bindings: fixes (William), enum support (St�phane Bidoul), 863 structured error reporting (St�phane Bidoul)</li> 864 <li>XInclude: various fixes for conformance, problem related to dictionnary 865 references (William & me), recursion (William)</li> 866 <li>xmlWriter: indentation (Lucas Brasilino), memory leaks (Alfred 867 Mickautsch),</li> 868 <li>xmlSchemas: normalizedString datatype (John Belmonte)</li> 869 <li>code cleanup for strings functions (William)</li> 870 <li>Windows: compiler patches (Mark Vakoc)</li> 871 <li>Parser optimizations, a few new XPath and dictionnary APIs for future 872 XSLT optimizations.</li> 873</ul> 874 875<h3>2.6.4: Dec 24 2003</h3> 876<ul> 877 <li>Windows build fixes (Igor Zlatkovic)</li> 878 <li>Some serious XInclude problems reported by Oleg Paraschenko and</li> 879 <li>Unix and Makefile packaging fixes (me, William Brack,</li> 880 <li>Documentation improvements (John Fleck, William Brack), example fix 881 (Lucas Brasilino)</li> 882 <li>bugfixes: xmlTextReaderExpand() with xmlReaderWalker, XPath handling of 883 NULL strings (William Brack) , API building reader or parser from 884 filedescriptor should not close it, changed XPath sorting to be stable 885 again (William Brack), xmlGetNodePath() generating '(null)' (William 886 Brack), DTD validation and namespace bug (William Brack), XML Schemas 887 double inclusion behaviour</li> 888</ul> 889 890<h3>2.6.3: Dec 10 2003</h3> 891<ul> 892 <li>documentation updates and cleanup (DV, William Brack, John Fleck)</li> 893 <li>added a repository of examples, examples from Aleksey Sanin, Dodji 894 Seketeli, Alfred Mickautsch</li> 895 <li>Windows updates: Mark Vakoc, Igor Zlatkovic, Eric Zurcher, Mingw 896 (Kenneth Haley)</li> 897 <li>Unicode range checking (William Brack)</li> 898 <li>code cleanup (William Brack)</li> 899 <li>Python bindings: doc (John Fleck), bug fixes</li> 900 <li>UTF-16 cleanup and BOM issues (William Brack)</li> 901 <li>bug fixes: ID and xmlReader validation, XPath (William Brack), 902 xmlWriter (Alfred Mickautsch), hash.h inclusion problem, HTML parser 903 (James Bursa), attribute defaulting and validation, some serialization 904 cleanups, XML_GET_LINE macro, memory debug when using threads (William 905 Brack), serialization of attributes and entities content, xmlWriter 906 (Daniel Schulman)</li> 907 <li>XInclude bugfix, new APIs and update to the last version including the 908 namespace change.</li> 909 <li>XML Schemas improvements: include (Robert Stepanek), import and 910 namespace handling, fixed the regression tests troubles, added examples 911 based on Eric van der Vlist book, regexp fixes</li> 912 <li>preliminary pattern support for streaming (needed for schemas 913 constraints), added xmlTextReaderPreservePattern() to collect subdocument 914 when streaming.</li> 915 <li>various fixes in the structured error handling</li> 916</ul> 917 918<h3>2.6.2: Nov 4 2003</h3> 919<ul> 920 <li>XPath context unregistration fixes</li> 921 <li>text node coalescing fixes (Mark Lilback)</li> 922 <li>API to screate a W3C Schemas from an existing document (Steve Ball)</li> 923 <li>BeOS patches (Marcin 'Shard' Konicki)</li> 924 <li>xmlStrVPrintf function added (Aleksey Sanin)</li> 925 <li>compilation fixes (Mark Vakoc)</li> 926 <li>stdin parsing fix (William Brack)</li> 927 <li>a posteriori DTD validation fixes</li> 928 <li>xmlReader bug fixes: Walker fixes, python bindings</li> 929 <li>fixed xmlStopParser() to really stop the parser and errors</li> 930 <li>always generate line numbers when using the new xmlReadxxx 931 functions</li> 932 <li>added XInclude support to the xmlReader interface</li> 933 <li>implemented XML_PARSE_NONET parser option</li> 934 <li>DocBook XSLT processing bug fixed</li> 935 <li>HTML serialization for <p> elements (William Brack and me)</li> 936 <li>XPointer failure in XInclude are now handled as resource errors</li> 937 <li>fixed xmllint --html to use the HTML serializer on output (added 938 --xmlout to implement the previous behaviour of saving it using the XML 939 serializer)</li> 940</ul> 941 942<h3>2.6.1: Oct 28 2003</h3> 943<ul> 944 <li>Mostly bugfixes after the big 2.6.0 changes</li> 945 <li>Unix compilation patches: libxml.m4 (Patrick Welche), warnings cleanup 946 (William Brack)</li> 947 <li>Windows compilation patches (Joachim Bauch, Stephane Bidoul, Igor 948 Zlatkovic)</li> 949 <li>xmlWriter bugfix (Alfred Mickautsch)</li> 950 <li>chvalid.[ch]: couple of fixes from Stephane Bidoul</li> 951 <li>context reset: error state reset, push parser reset (Graham 952 Bennett)</li> 953 <li>context reuse: generate errors if file is not readable</li> 954 <li>defaulted attributes for element coming from internal entities 955 (Stephane Bidoul)</li> 956 <li>Python: tab and spaces mix (William Brack)</li> 957 <li>Error handler could crash in DTD validation in 2.6.0</li> 958 <li>xmlReader: do not use the document or element _private field</li> 959 <li>testSAX.c: avoid a problem with some PIs (Massimo Morara)</li> 960 <li>general bug fixes: mandatory encoding in text decl, serializing 961 Document Fragment nodes, xmlSearchNs 2.6.0 problem (Kasimier Buchcik), 962 XPath errors not reported, slow HTML parsing of large documents.</li> 963</ul> 964 965<h3>2.6.0: Oct 20 2003</h3> 966<ul> 967 <li>Major revision release: should be API and ABI compatible but got a lot 968 of change</li> 969 <li>Increased the library modularity, far more options can be stripped out, 970 a --with-minimum configuration will weight around 160KBytes</li> 971 <li>Use per parser and per document dictionnary, allocate names and small 972 text nodes from the dictionnary</li> 973 <li>Switch to a SAX2 like parser rewrote most of the XML parser core, 974 provides namespace resolution and defaulted attributes, minimize memory 975 allocations and copies, namespace checking and specific error handling, 976 immutable buffers, make predefined entities static structures, etc...</li> 977 <li>rewrote all the error handling in the library, all errors can be 978 intercepted at a structured level, with precise information 979 available.</li> 980 <li>New simpler and more generic XML and HTML parser APIs, allowing to 981 easilly modify the parsing options and reuse parser context for multiple 982 consecutive documents.</li> 983 <li>Similar new APIs for the xmlReader, for options and reuse, provided new 984 functions to access content as const strings, use them for Python 985 bindings</li> 986 <li>a lot of other smaller API improvements: xmlStrPrintf (Aleksey Sanin), 987 Walker i.e. reader on a document tree based on Alfred Mickautsch code, 988 make room in nodes for line numbers, reference counting and future PSVI 989 extensions, generation of character ranges to be checked with faster 990 algorithm (William), xmlParserMaxDepth (Crutcher Dunnavant), buffer 991 access</li> 992 <li>New xmlWriter API provided by Alfred Mickautsch</li> 993 <li>Schemas: base64 support by Anthony Carrico</li> 994 <li>Parser<->HTTP integration fix, proper processing of the Mime-Type 995 and charset informations if available.</li> 996 <li>Relax-NG: bug fixes including the one reported by Martijn Faassen and 997 zeroOrMore, better error reporting.</li> 998 <li>Python bindings (St�phane Bidoul), never use stdout for errors 999 output</li> 1000 <li>Portability: all the headers have macros for export and calling 1001 convention definitions (Igor Zlatkovic), VMS update (Craig A. Berry), 1002 Windows: threads (Jesse Pelton), Borland compiler (Eric Zurcher, Igor), 1003 Mingw (Igor), typos (Mark Vakoc), beta version (Stephane Bidoul), 1004 warning cleanups on AIX and MIPS compilers (William Brack), BeOS (Marcin 1005 'Shard' Konicki)</li> 1006 <li>Documentation fixes and README (William Brack), search fix (William), 1007 tutorial updates (John Fleck), namespace docs (Stefan Kost)</li> 1008 <li>Bug fixes: xmlCleanupParser (Dave Beckett), threading uninitialized 1009 mutexes, HTML doctype lowercase, SAX/IO (William), compression detection 1010 and restore (William), attribute declaration in DTDs (William), namespace 1011 on attribute in HTML output (William), input filename (Rob Richards), 1012 namespace DTD validation, xmlReplaceNode (Chris Ryland), I/O callbacks 1013 (Markus Keim), CDATA serialization (Shaun McCance), xmlReader (Peter 1014 Derr), high codepoint charref like &#x10FFFF;, buffer access in push 1015 mode (Justin Fletcher), TLS threads on Windows (Jesse Pelton), XPath bug 1016 (William), xmlCleanupParser (Marc Liyanage), CDATA output (William), HTTP 1017 error handling.</li> 1018 <li>xmllint options: --dtdvalidfpi for Tobias Reif, --sax1 for compat 1019 testing, --nodict for building without tree dictionnary, --nocdata to 1020 replace CDATA by text, --nsclean to remove surperfluous namespace 1021 declarations</li> 1022 <li>added xml2-config --libtool-libs option from Kevin P. Fleming</li> 1023 <li>a lot of profiling and tuning of the code, speedup patch for 1024 xmlSearchNs() by Luca Padovani. The xmlReader should do far less 1025 allocation and it speed should get closer to SAX. Chris Anderson worked 1026 on speeding and cleaning up repetitive checking code.</li> 1027 <li>cleanup of "make tests"</li> 1028 <li>libxml-2.0-uninstalled.pc from Malcolm Tredinnick</li> 1029 <li>deactivated the broken docBook SGML parser code and plugged the XML 1030 parser instead.</li> 1031</ul> 1032 1033<h3>2.5.11: Sep 9 2003</h3> 1034 1035<p>A bugfix only release:</p> 1036<ul> 1037 <li>risk of crash in Relax-NG</li> 1038 <li>risk of crash when using multithreaded programs</li> 1039</ul> 1040 1041<h3>2.5.10: Aug 15 2003</h3> 1042 1043<p>A bugfixes only release</p> 1044<ul> 1045 <li>Windows Makefiles (William Brack)</li> 1046 <li>UTF-16 support fixes (Mark Itzcovitz)</li> 1047 <li>Makefile and portability (William Brack) automake, Linux alpha, Mingw 1048 on Windows (Mikhail Grushinskiy)</li> 1049 <li>HTML parser (Oliver Stoeneberg)</li> 1050 <li>XInclude performance problem reported by Kevin Ruscoe</li> 1051 <li>XML parser performance problem reported by Grant Goodale</li> 1052 <li>xmlSAXParseDTD() bug fix from Malcolm Tredinnick</li> 1053 <li>and a couple other cleanup</li> 1054</ul> 1055 1056<h3>2.5.9: Aug 9 2003</h3> 1057<ul> 1058 <li>bugfixes: IPv6 portability, xmlHasNsProp (Markus Keim), Windows build 1059 (Wiliam Brake, Jesse Pelton, Igor), Schemas (Peter Sobisch), threading 1060 (Rob Richards), hexBinary type (), UTF-16 BOM (Dodji Seketeli), 1061 xmlReader, Relax-NG schemas compilation, namespace handling, EXSLT (Sean 1062 Griffin), HTML parsing problem (William Brack), DTD validation for mixed 1063 content + namespaces, HTML serialization, library initialization, 1064 progressive HTML parser</li> 1065 <li>better interfaces for Relax-NG error handling (Joachim Bauch, )</li> 1066 <li>adding xmlXIncludeProcessTree() for XInclud'ing in a subtree</li> 1067 <li>doc fixes and improvements (John Fleck)</li> 1068 <li>configure flag for -with-fexceptions when embedding in C++</li> 1069 <li>couple of new UTF-8 helper functions (William Brack)</li> 1070 <li>general encoding cleanup + ISO-8859-x without iconv (Peter Jacobi)</li> 1071 <li>xmlTextReader cleanup + enum for node types (Bjorn Reese)</li> 1072 <li>general compilation/warning cleanup Solaris/HP-UX/... (William 1073 Brack)</li> 1074</ul> 1075 1076<h3>2.5.8: Jul 6 2003</h3> 1077<ul> 1078 <li>bugfixes: XPath, XInclude, file/URI mapping, UTF-16 save (Mark 1079 Itzcovitz), UTF-8 checking, URI saving, error printing (William Brack), 1080 PI related memleak, compilation without schemas or without xpath (Joerg 1081 Schmitz-Linneweber/Garry Pennington), xmlUnlinkNode problem with DTDs, 1082 rpm problem on , i86_64, removed a few compilation problems from 2.5.7, 1083 xmlIOParseDTD, and xmlSAXParseDTD (Malcolm Tredinnick)</li> 1084 <li>portability: DJGPP (MsDos) , OpenVMS (Craig A. Berry)</li> 1085 <li>William Brack fixed multithreading lock problems</li> 1086 <li>IPv6 patch for FTP and HTTP accesses (Archana Shah/Wipro)</li> 1087 <li>Windows fixes (Igor Zlatkovic, Eric Zurcher), threading (St�phane 1088 Bidoul)</li> 1089 <li>A few W3C Schemas Structure improvements</li> 1090 <li>W3C Schemas Datatype improvements (Charlie Bozeman)</li> 1091 <li>Python bindings for thread globals (St�phane Bidoul), and method/class 1092 generator</li> 1093 <li>added --nonet option to xmllint</li> 1094 <li>documentation improvements (John Fleck)</li> 1095</ul> 1096 1097<h3>2.5.7: Apr 25 2003</h3> 1098<ul> 1099 <li>Relax-NG: Compiling to regexp and streaming validation on top of the 1100 xmlReader interface, added to xmllint --stream</li> 1101 <li>xmlReader: Expand(), Next() and DOM access glue, bug fixes</li> 1102 <li>Support for large files: RGN validated a 4.5GB instance</li> 1103 <li>Thread support is now configured in by default</li> 1104 <li>Fixes: update of the Trio code (Bjorn), WXS Date and Duration fixes 1105 (Charles Bozeman), DTD and namespaces (Brent Hendricks), HTML push parser 1106 and zero bytes handling, some missing Windows file path conversions, 1107 behaviour of the parser and validator in the presence of "out of memory" 1108 error conditions</li> 1109 <li>extended the API to be able to plug a garbage collecting memory 1110 allocator, added xmlMallocAtomic() and modified the allocations 1111 accordingly.</li> 1112 <li>Performances: removed excessive malloc() calls, speedup of the push and 1113 xmlReader interfaces, removed excessive thread locking</li> 1114 <li>Documentation: man page (John Fleck), xmlReader documentation</li> 1115 <li>Python: adding binding for xmlCatalogAddLocal (Brent M Hendricks)</li> 1116</ul> 1117 1118<h3>2.5.6: Apr 1 2003</h3> 1119<ul> 1120 <li>Fixed W3C XML Schemas datatype, should be compliant now except for 1121 binHex and base64 which are not supported yet.</li> 1122 <li>bug fixes: non-ASCII IDs, HTML output, XInclude on large docs and 1123 XInclude entities handling, encoding detection on external subsets, XML 1124 Schemas bugs and memory leaks, HTML parser (James Bursa)</li> 1125 <li>portability: python/trio (Albert Chin), Sun compiler warnings</li> 1126 <li>documentation: added --relaxng option to xmllint man page (John)</li> 1127 <li>improved error reporting: xml:space, start/end tag mismatches, Relax NG 1128 errors</li> 1129</ul> 1130 1131<h3>2.5.5: Mar 24 2003</h3> 1132<ul> 1133 <li>Lot of fixes on the Relax NG implementation. More testing including 1134 DocBook and TEI examples.</li> 1135 <li>Increased the support for W3C XML Schemas datatype</li> 1136 <li>Several bug fixes in the URI handling layer</li> 1137 <li>Bug fixes: HTML parser, xmlReader, DTD validation, XPath, encoding 1138 conversion, line counting in the parser.</li> 1139 <li>Added support for $XMLLINT_INDENT environment variable, FTP delete</li> 1140 <li>Fixed the RPM spec file name</li> 1141</ul> 1142 1143<h3>2.5.4: Feb 20 2003</h3> 1144<ul> 1145 <li>Conformance testing and lot of fixes on Relax NG and XInclude 1146 implementation</li> 1147 <li>Implementation of XPointer element() scheme</li> 1148 <li>Bug fixes: XML parser, XInclude entities merge, validity checking on 1149 namespaces, 1150 <p>2 serialization bugs, node info generation problems, a DTD regexp 1151 generation problem.</p> 1152 </li> 1153 <li>Portability: windows updates and path canonicalization (Igor)</li> 1154 <li>A few typo fixes (Kjartan Maraas)</li> 1155 <li>Python bindings generator fixes (Stephane Bidoul)</li> 1156</ul> 1157 1158<h3>2.5.3: Feb 10 2003</h3> 1159<ul> 1160 <li>RelaxNG and XML Schemas datatypes improvements, and added a first 1161 version of RelaxNG Python bindings</li> 1162 <li>Fixes: XLink (Sean Chittenden), XInclude (Sean Chittenden), API fix for 1163 serializing namespace nodes, encoding conversion bug, XHTML1 1164 serialization</li> 1165 <li>Portability fixes: Windows (Igor), AMD 64bits RPM spec file</li> 1166</ul> 1167 1168<h3>2.5.2: Feb 5 2003</h3> 1169<ul> 1170 <li>First implementation of RelaxNG, added --relaxng flag to xmllint</li> 1171 <li>Schemas support now compiled in by default.</li> 1172 <li>Bug fixes: DTD validation, namespace checking, XInclude and entities, 1173 delegateURI in XML Catalogs, HTML parser, XML reader (St�phane Bidoul), 1174 XPath parser and evaluation, UTF8ToUTF8 serialization, XML reader memory 1175 consumption, HTML parser, HTML serialization in the presence of 1176 namespaces</li> 1177 <li>added an HTML API to check elements and attributes.</li> 1178 <li>Documentation improvement, PDF for the tutorial (John Fleck), doc 1179 patches (Stefan Kost)</li> 1180 <li>Portability fixes: NetBSD (Julio Merino), Windows (Igor Zlatkovic)</li> 1181 <li>Added python bindings for XPointer, contextual error reporting 1182 (St�phane Bidoul)</li> 1183 <li>URI/file escaping problems (Stefano Zacchiroli)</li> 1184</ul> 1185 1186<h3>2.5.1: Jan 8 2003</h3> 1187<ul> 1188 <li>Fixes a memory leak and configuration/compilation problems in 2.5.0</li> 1189 <li>documentation updates (John)</li> 1190 <li>a couple of XmlTextReader fixes</li> 1191</ul> 1192 1193<h3>2.5.0: Jan 6 2003</h3> 1194<ul> 1195 <li>New <a href="xmlreader.html">XmltextReader interface</a> based on C# 1196 API (with help of St�phane Bidoul)</li> 1197 <li>Windows: more exports, including the new API (Igor)</li> 1198 <li>XInclude fallback fix</li> 1199 <li>Python: bindings for the new API, packaging (St�phane Bidoul), 1200 drv_libxml2.py Python xml.sax driver (St�phane Bidoul), fixes, speedup 1201 and iterators for Python-2.2 (Hannu Krosing)</li> 1202 <li>Tutorial fixes (john Fleck and Niraj Tolia) xmllint man update 1203 (John)</li> 1204 <li>Fix an XML parser bug raised by Vyacheslav Pindyura</li> 1205 <li>Fix for VMS serialization (Nigel Hall) and config (Craig A. Berry)</li> 1206 <li>Entities handling fixes</li> 1207 <li>new API to optionally track node creation and deletion (Lukas 1208 Schroeder)</li> 1209 <li>Added documentation for the XmltextReader interface and some <a 1210 href="guidelines.html">XML guidelines</a></li> 1211</ul> 1212 1213<h3>2.4.30: Dec 12 2002</h3> 1214<ul> 1215 <li>2.4.29 broke the python bindings, rereleasing</li> 1216 <li>Improvement/fixes of the XML API generator, and couple of minor code 1217 fixes.</li> 1218</ul> 1219 1220<h3>2.4.29: Dec 11 2002</h3> 1221<ul> 1222 <li>Windows fixes (Igor): Windows CE port, pthread linking, python bindings 1223 (St�phane Bidoul), Mingw (Magnus Henoch), and export list updates</li> 1224 <li>Fix for prev in python bindings (ERDI Gergo)</li> 1225 <li>Fix for entities handling (Marcus Clarke)</li> 1226 <li>Refactored the XML and HTML dumps to a single code path, fixed XHTML1 1227 dump</li> 1228 <li>Fix for URI parsing when handling URNs with fragment identifiers</li> 1229 <li>Fix for HTTP URL escaping problem</li> 1230 <li>added an TextXmlReader (C#) like API (work in progress)</li> 1231 <li>Rewrote the API in XML generation script, includes a C parser and saves 1232 more informations needed for C# bindings</li> 1233</ul> 1234 1235<h3>2.4.28: Nov 22 2002</h3> 1236<ul> 1237 <li>a couple of python binding fixes</li> 1238 <li>2 bug fixes in the XML push parser</li> 1239 <li>potential memory leak removed (Martin Stoilov)</li> 1240 <li>fix to the configure script for Unix (Dimitri Papadopoulos)</li> 1241 <li>added encoding support for XInclude parse="text"</li> 1242 <li>autodetection of XHTML1 and specific serialization rules added</li> 1243 <li>nasty threading bug fixed (William Brack)</li> 1244</ul> 1245 1246<h3>2.4.27: Nov 17 2002</h3> 1247<ul> 1248 <li>fixes for the Python bindings</li> 1249 <li>a number of bug fixes: SGML catalogs, xmlParseBalancedChunkMemory(), 1250 HTML parser, Schemas (Charles Bozeman), document fragment support 1251 (Christian Glahn), xmlReconciliateNs (Brian Stafford), XPointer, 1252 xmlFreeNode(), xmlSAXParseMemory (Peter Jones), xmlGetNodePath (Petr 1253 Pajas), entities processing</li> 1254 <li>added grep to xmllint --shell</li> 1255 <li>VMS update patch from Craig A. Berry</li> 1256 <li>cleanup of the Windows build with support for more compilers (Igor), 1257 better thread support on Windows</li> 1258 <li>cleanup of Unix Makefiles and spec file</li> 1259 <li>Improvements to the documentation (John Fleck)</li> 1260</ul> 1261 1262<h3>2.4.26: Oct 18 2002</h3> 1263<ul> 1264 <li>Patches for Windows CE port, improvements on Windows paths handling</li> 1265 <li>Fixes to the validation code (DTD and Schemas), xmlNodeGetPath() , 1266 HTML serialization, Namespace compliance, and a number of small 1267 problems</li> 1268</ul> 1269 1270<h3>2.4.25: Sep 26 2002</h3> 1271<ul> 1272 <li>A number of bug fixes: XPath, validation, Python bindings, DOM and 1273 tree, xmlI/O, Html</li> 1274 <li>Serious rewrite of XInclude</li> 1275 <li>Made XML Schemas regexp part of the default build and APIs, small fix 1276 and improvement of the regexp core</li> 1277 <li>Changed the validation code to reuse XML Schemas regexp APIs</li> 1278 <li>Better handling of Windows file paths, improvement of Makefiles (Igor, 1279 Daniel Gehriger, Mark Vakoc)</li> 1280 <li>Improved the python I/O bindings, the tests, added resolver and regexp 1281 APIs</li> 1282 <li>New logos from Marc Liyanage</li> 1283 <li>Tutorial improvements: John Fleck, Christopher Harris</li> 1284 <li>Makefile: Fixes for AMD x86_64 (Mandrake), DESTDIR (Christophe 1285 Merlet)</li> 1286 <li>removal of all stderr/perror use for error reporting</li> 1287 <li>Better error reporting: XPath and DTD validation</li> 1288 <li>update of the trio portability layer (Bjorn Reese)</li> 1289</ul> 1290 1291<p><strong>2.4.24: Aug 22 2002</strong></p> 1292<ul> 1293 <li>XPath fixes (William), xf:escape-uri() (Wesley Terpstra)</li> 1294 <li>Python binding fixes: makefiles (William), generator, rpm build, x86-64 1295 (fcrozat)</li> 1296 <li>HTML <style> and boolean attributes serializer fixes</li> 1297 <li>C14N improvements by Aleksey</li> 1298 <li>doc cleanups: Rick Jones</li> 1299 <li>Windows compiler makefile updates: Igor and Elizabeth Barham</li> 1300 <li>XInclude: implementation of fallback and xml:base fixup added</li> 1301</ul> 1302 1303<h3>2.4.23: July 6 2002</h3> 1304<ul> 1305 <li>performances patches: Peter Jacobi</li> 1306 <li>c14n fixes, testsuite and performances: Aleksey Sanin</li> 1307 <li>added xmlDocFormatDump: Chema Celorio</li> 1308 <li>new tutorial: John Fleck</li> 1309 <li>new hash functions and performances: Sander Vesik, portability fix from 1310 Peter Jacobi</li> 1311 <li>a number of bug fixes: XPath (William Brack, Richard Jinks), XML and 1312 HTML parsers, ID lookup function</li> 1313 <li>removal of all remaining sprintf: Aleksey Sanin</li> 1314</ul> 1315 1316<h3>2.4.22: May 27 2002</h3> 1317<ul> 1318 <li>a number of bug fixes: configure scripts, base handling, parser, memory 1319 usage, HTML parser, XPath, documentation (Christian Cornelssen), 1320 indentation, URI parsing</li> 1321 <li>Optimizations for XMLSec, fixing and making public some of the network 1322 protocol handlers (Aleksey)</li> 1323 <li>performance patch from Gary Pennington</li> 1324 <li>Charles Bozeman provided date and time support for XML Schemas 1325 datatypes</li> 1326</ul> 1327 1328<h3>2.4.21: Apr 29 2002</h3> 1329 1330<p>This release is both a bug fix release and also contains the early XML 1331Schemas <a href="http://www.w3.org/TR/xmlschema-1/">structures</a> and <a 1332href="http://www.w3.org/TR/xmlschema-2/">datatypes</a> code, beware, all 1333interfaces are likely to change, there is huge holes, it is clearly a work in 1334progress and don't even think of putting this code in a production system, 1335it's actually not compiled in by default. The real fixes are:</p> 1336<ul> 1337 <li>a couple of bugs or limitations introduced in 2.4.20</li> 1338 <li>patches for Borland C++ and MSC by Igor</li> 1339 <li>some fixes on XPath strings and conformance patches by Richard 1340 Jinks</li> 1341 <li>patch from Aleksey for the ExcC14N specification</li> 1342 <li>OSF/1 bug fix by Bjorn</li> 1343</ul> 1344 1345<h3>2.4.20: Apr 15 2002</h3> 1346<ul> 1347 <li>bug fixes: file descriptor leak, XPath, HTML output, DTD validation</li> 1348 <li>XPath conformance testing by Richard Jinks</li> 1349 <li>Portability fixes: Solaris, MPE/iX, Windows, OSF/1, python bindings, 1350 libxml.m4</li> 1351</ul> 1352 1353<h3>2.4.19: Mar 25 2002</h3> 1354<ul> 1355 <li>bug fixes: half a dozen XPath bugs, Validation, ISO-Latin to UTF8 1356 encoder</li> 1357 <li>portability fixes in the HTTP code</li> 1358 <li>memory allocation checks using valgrind, and profiling tests</li> 1359 <li>revamp of the Windows build and Makefiles</li> 1360</ul> 1361 1362<h3>2.4.18: Mar 18 2002</h3> 1363<ul> 1364 <li>bug fixes: tree, SAX, canonicalization, validation, portability, 1365 XPath</li> 1366 <li>removed the --with-buffer option it was becoming unmaintainable</li> 1367 <li>serious cleanup of the Python makefiles</li> 1368 <li>speedup patch to XPath very effective for DocBook stylesheets</li> 1369 <li>Fixes for Windows build, cleanup of the documentation</li> 1370</ul> 1371 1372<h3>2.4.17: Mar 8 2002</h3> 1373<ul> 1374 <li>a lot of bug fixes, including "namespace nodes have no parents in 1375 XPath"</li> 1376 <li>fixed/improved the Python wrappers, added more examples and more 1377 regression tests, XPath extension functions can now return node-sets</li> 1378 <li>added the XML Canonicalization support from Aleksey Sanin</li> 1379</ul> 1380 1381<h3>2.4.16: Feb 20 2002</h3> 1382<ul> 1383 <li>a lot of bug fixes, most of them were triggered by the XML Testsuite 1384 from OASIS and W3C. Compliance has been significantly improved.</li> 1385 <li>a couple of portability fixes too.</li> 1386</ul> 1387 1388<h3>2.4.15: Feb 11 2002</h3> 1389<ul> 1390 <li>Fixed the Makefiles, especially the python module ones</li> 1391 <li>A few bug fixes and cleanup</li> 1392 <li>Includes cleanup</li> 1393</ul> 1394 1395<h3>2.4.14: Feb 8 2002</h3> 1396<ul> 1397 <li>Change of License to the <a 1398 href="http://www.opensource.org/licenses/mit-license.html">MIT 1399 License</a> basically for integration in XFree86 codebase, and removing 1400 confusion around the previous dual-licensing</li> 1401 <li>added Python bindings, beta software but should already be quite 1402 complete</li> 1403 <li>a large number of fixes and cleanups, especially for all tree 1404 manipulations</li> 1405 <li>cleanup of the headers, generation of a reference API definition in 1406 XML</li> 1407</ul> 1408 1409<h3>2.4.13: Jan 14 2002</h3> 1410<ul> 1411 <li>update of the documentation: John Fleck and Charlie Bozeman</li> 1412 <li>cleanup of timing code from Justin Fletcher</li> 1413 <li>fixes for Windows and initial thread support on Win32: Igor and Serguei 1414 Narojnyi</li> 1415 <li>Cygwin patch from Robert Collins</li> 1416 <li>added xmlSetEntityReferenceFunc() for Keith Isdale work on xsldbg</li> 1417</ul> 1418 1419<h3>2.4.12: Dec 7 2001</h3> 1420<ul> 1421 <li>a few bug fixes: thread (Gary Pennington), xmllint (Geert Kloosterman), 1422 XML parser (Robin Berjon), XPointer (Danny Jamshy), I/O cleanups 1423 (robert)</li> 1424 <li>Eric Lavigne contributed project files for MacOS</li> 1425 <li>some makefiles cleanups</li> 1426</ul> 1427 1428<h3>2.4.11: Nov 26 2001</h3> 1429<ul> 1430 <li>fixed a couple of errors in the includes, fixed a few bugs, some code 1431 cleanups</li> 1432 <li>xmllint man pages improvement by Heiko Rupp</li> 1433 <li>updated VMS build instructions from John A Fotheringham</li> 1434 <li>Windows Makefiles updates from Igor</li> 1435</ul> 1436 1437<h3>2.4.10: Nov 10 2001</h3> 1438<ul> 1439 <li>URI escaping fix (Joel Young)</li> 1440 <li>added xmlGetNodePath() (for paths or XPointers generation)</li> 1441 <li>Fixes namespace handling problems when using DTD and validation</li> 1442 <li>improvements on xmllint: Morus Walter patches for --format and 1443 --encode, Stefan Kost and Heiko Rupp improvements on the --shell</li> 1444 <li>fixes for xmlcatalog linking pointed by Weiqi Gao</li> 1445 <li>fixes to the HTML parser</li> 1446</ul> 1447 1448<h3>2.4.9: Nov 6 2001</h3> 1449<ul> 1450 <li>fixes more catalog bugs</li> 1451 <li>avoid a compilation problem, improve xmlGetLineNo()</li> 1452</ul> 1453 1454<h3>2.4.8: Nov 4 2001</h3> 1455<ul> 1456 <li>fixed SGML catalogs broken in previous release, updated xmlcatalog 1457 tool</li> 1458 <li>fixed a compile errors and some includes troubles.</li> 1459</ul> 1460 1461<h3>2.4.7: Oct 30 2001</h3> 1462<ul> 1463 <li>exported some debugging interfaces</li> 1464 <li>serious rewrite of the catalog code</li> 1465 <li>integrated Gary Pennington thread safety patch, added configure option 1466 and regression tests</li> 1467 <li>removed an HTML parser bug</li> 1468 <li>fixed a couple of potentially serious validation bugs</li> 1469 <li>integrated the SGML DocBook support in xmllint</li> 1470 <li>changed the nanoftp anonymous login passwd</li> 1471 <li>some I/O cleanup and a couple of interfaces for Perl wrapper</li> 1472 <li>general bug fixes</li> 1473 <li>updated xmllint man page by John Fleck</li> 1474 <li>some VMS and Windows updates</li> 1475</ul> 1476 1477<h3>2.4.6: Oct 10 2001</h3> 1478<ul> 1479 <li>added an updated man pages by John Fleck</li> 1480 <li>portability and configure fixes</li> 1481 <li>an infinite loop on the HTML parser was removed (William)</li> 1482 <li>Windows makefile patches from Igor</li> 1483 <li>fixed half a dozen bugs reported for libxml or libxslt</li> 1484 <li>updated xmlcatalog to be able to modify SGML super catalogs</li> 1485</ul> 1486 1487<h3>2.4.5: Sep 14 2001</h3> 1488<ul> 1489 <li>Remove a few annoying bugs in 2.4.4</li> 1490 <li>forces the HTML serializer to output decimal charrefs since some 1491 version of Netscape can't handle hexadecimal ones</li> 1492</ul> 1493 1494<h3>1.8.16: Sep 14 2001</h3> 1495<ul> 1496 <li>maintenance release of the old libxml1 branch, couple of bug and 1497 portability fixes</li> 1498</ul> 1499 1500<h3>2.4.4: Sep 12 2001</h3> 1501<ul> 1502 <li>added --convert to xmlcatalog, bug fixes and cleanups of XML 1503 Catalog</li> 1504 <li>a few bug fixes and some portability changes</li> 1505 <li>some documentation cleanups</li> 1506</ul> 1507 1508<h3>2.4.3: Aug 23 2001</h3> 1509<ul> 1510 <li>XML Catalog support see the doc</li> 1511 <li>New NaN/Infinity floating point code</li> 1512 <li>A few bug fixes</li> 1513</ul> 1514 1515<h3>2.4.2: Aug 15 2001</h3> 1516<ul> 1517 <li>adds xmlLineNumbersDefault() to control line number generation</li> 1518 <li>lot of bug fixes</li> 1519 <li>the Microsoft MSC projects files should now be up to date</li> 1520 <li>inheritance of namespaces from DTD defaulted attributes</li> 1521 <li>fixes a serious potential security bug</li> 1522 <li>added a --format option to xmllint</li> 1523</ul> 1524 1525<h3>2.4.1: July 24 2001</h3> 1526<ul> 1527 <li>possibility to keep line numbers in the tree</li> 1528 <li>some computation NaN fixes</li> 1529 <li>extension of the XPath API</li> 1530 <li>cleanup for alpha and ia64 targets</li> 1531 <li>patch to allow saving through HTTP PUT or POST</li> 1532</ul> 1533 1534<h3>2.4.0: July 10 2001</h3> 1535<ul> 1536 <li>Fixed a few bugs in XPath, validation, and tree handling.</li> 1537 <li>Fixed XML Base implementation, added a couple of examples to the 1538 regression tests</li> 1539 <li>A bit of cleanup</li> 1540</ul> 1541 1542<h3>2.3.14: July 5 2001</h3> 1543<ul> 1544 <li>fixed some entities problems and reduce memory requirement when 1545 substituting them</li> 1546 <li>lots of improvements in the XPath queries interpreter can be 1547 substantially faster</li> 1548 <li>Makefiles and configure cleanups</li> 1549 <li>Fixes to XPath variable eval, and compare on empty node set</li> 1550 <li>HTML tag closing bug fixed</li> 1551 <li>Fixed an URI reference computation problem when validating</li> 1552</ul> 1553 1554<h3>2.3.13: June 28 2001</h3> 1555<ul> 1556 <li>2.3.12 configure.in was broken as well as the push mode XML parser</li> 1557 <li>a few more fixes for compilation on Windows MSC by Yon Derek</li> 1558</ul> 1559 1560<h3>1.8.14: June 28 2001</h3> 1561<ul> 1562 <li>Zbigniew Chyla gave a patch to use the old XML parser in push mode</li> 1563 <li>Small Makefile fix</li> 1564</ul> 1565 1566<h3>2.3.12: June 26 2001</h3> 1567<ul> 1568 <li>lots of cleanup</li> 1569 <li>a couple of validation fix</li> 1570 <li>fixed line number counting</li> 1571 <li>fixed serious problems in the XInclude processing</li> 1572 <li>added support for UTF8 BOM at beginning of entities</li> 1573 <li>fixed a strange gcc optimizer bugs in xpath handling of float, gcc-3.0 1574 miscompile uri.c (William), Thomas Leitner provided a fix for the 1575 optimizer on Tru64</li> 1576 <li>incorporated Yon Derek and Igor Zlatkovic fixes and improvements for 1577 compilation on Windows MSC</li> 1578 <li>update of libxml-doc.el (Felix Natter)</li> 1579 <li>fixed 2 bugs in URI normalization code</li> 1580</ul> 1581 1582<h3>2.3.11: June 17 2001</h3> 1583<ul> 1584 <li>updates to trio, Makefiles and configure should fix some portability 1585 problems (alpha)</li> 1586 <li>fixed some HTML serialization problems (pre, script, and block/inline 1587 handling), added encoding aware APIs, cleanup of this code</li> 1588 <li>added xmlHasNsProp()</li> 1589 <li>implemented a specific PI for encoding support in the DocBook SGML 1590 parser</li> 1591 <li>some XPath fixes (-Infinity, / as a function parameter and namespaces 1592 node selection)</li> 1593 <li>fixed a performance problem and an error in the validation code</li> 1594 <li>fixed XInclude routine to implement the recursive behaviour</li> 1595 <li>fixed xmlFreeNode problem when libxml is included statically twice</li> 1596 <li>added --version to xmllint for bug reports</li> 1597</ul> 1598 1599<h3>2.3.10: June 1 2001</h3> 1600<ul> 1601 <li>fixed the SGML catalog support</li> 1602 <li>a number of reported bugs got fixed, in XPath, iconv detection, 1603 XInclude processing</li> 1604 <li>XPath string function should now handle unicode correctly</li> 1605</ul> 1606 1607<h3>2.3.9: May 19 2001</h3> 1608 1609<p>Lots of bugfixes, and added a basic SGML catalog support:</p> 1610<ul> 1611 <li>HTML push bugfix #54891 and another patch from Jonas Borgstr�m</li> 1612 <li>some serious speed optimization again</li> 1613 <li>some documentation cleanups</li> 1614 <li>trying to get better linking on Solaris (-R)</li> 1615 <li>XPath API cleanup from Thomas Broyer</li> 1616 <li>Validation bug fixed #54631, added a patch from Gary Pennington, fixed 1617 xmlValidGetValidElements()</li> 1618 <li>Added an INSTALL file</li> 1619 <li>Attribute removal added to API: #54433</li> 1620 <li>added a basic support for SGML catalogs</li> 1621 <li>fixed xmlKeepBlanksDefault(0) API</li> 1622 <li>bugfix in xmlNodeGetLang()</li> 1623 <li>fixed a small configure portability problem</li> 1624 <li>fixed an inversion of SYSTEM and PUBLIC identifier in HTML document</li> 1625</ul> 1626 1627<h3>1.8.13: May 14 2001</h3> 1628<ul> 1629 <li>bugfixes release of the old libxml1 branch used by Gnome</li> 1630</ul> 1631 1632<h3>2.3.8: May 3 2001</h3> 1633<ul> 1634 <li>Integrated an SGML DocBook parser for the Gnome project</li> 1635 <li>Fixed a few things in the HTML parser</li> 1636 <li>Fixed some XPath bugs raised by XSLT use, tried to fix the floating 1637 point portability issue</li> 1638 <li>Speed improvement (8M/s for SAX, 3M/s for DOM, 1.5M/s for 1639 DOM+validation using the XML REC as input and a 700MHz celeron).</li> 1640 <li>incorporated more Windows cleanup</li> 1641 <li>added xmlSaveFormatFile()</li> 1642 <li>fixed problems in copying nodes with entities references (gdome)</li> 1643 <li>removed some troubles surrounding the new validation module</li> 1644</ul> 1645 1646<h3>2.3.7: April 22 2001</h3> 1647<ul> 1648 <li>lots of small bug fixes, corrected XPointer</li> 1649 <li>Non deterministic content model validation support</li> 1650 <li>added xmlDocCopyNode for gdome2</li> 1651 <li>revamped the way the HTML parser handles end of tags</li> 1652 <li>XPath: corrections of namespaces support and number formatting</li> 1653 <li>Windows: Igor Zlatkovic patches for MSC compilation</li> 1654 <li>HTML output fixes from P C Chow and William M. Brack</li> 1655 <li>Improved validation speed sensible for DocBook</li> 1656 <li>fixed a big bug with ID declared in external parsed entities</li> 1657 <li>portability fixes, update of Trio from Bjorn Reese</li> 1658</ul> 1659 1660<h3>2.3.6: April 8 2001</h3> 1661<ul> 1662 <li>Code cleanup using extreme gcc compiler warning options, found and 1663 cleared half a dozen potential problem</li> 1664 <li>the Eazel team found an XML parser bug</li> 1665 <li>cleaned up the user of some of the string formatting function. used the 1666 trio library code to provide the one needed when the platform is missing 1667 them</li> 1668 <li>xpath: removed a memory leak and fixed the predicate evaluation 1669 problem, extended the testsuite and cleaned up the result. XPointer seems 1670 broken ...</li> 1671</ul> 1672 1673<h3>2.3.5: Mar 23 2001</h3> 1674<ul> 1675 <li>Biggest change is separate parsing and evaluation of XPath expressions, 1676 there is some new APIs for this too</li> 1677 <li>included a number of bug fixes(XML push parser, 51876, notations, 1678 52299)</li> 1679 <li>Fixed some portability issues</li> 1680</ul> 1681 1682<h3>2.3.4: Mar 10 2001</h3> 1683<ul> 1684 <li>Fixed bugs #51860 and #51861</li> 1685 <li>Added a global variable xmlDefaultBufferSize to allow default buffer 1686 size to be application tunable.</li> 1687 <li>Some cleanup in the validation code, still a bug left and this part 1688 should probably be rewritten to support ambiguous content model :-\</li> 1689 <li>Fix a couple of serious bugs introduced or raised by changes in 2.3.3 1690 parser</li> 1691 <li>Fixed another bug in xmlNodeGetContent()</li> 1692 <li>Bjorn fixed XPath node collection and Number formatting</li> 1693 <li>Fixed a loop reported in the HTML parsing</li> 1694 <li>blank space are reported even if the Dtd content model proves that they 1695 are formatting spaces, this is for XML conformance</li> 1696</ul> 1697 1698<h3>2.3.3: Mar 1 2001</h3> 1699<ul> 1700 <li>small change in XPath for XSLT</li> 1701 <li>documentation cleanups</li> 1702 <li>fix in validation by Gary Pennington</li> 1703 <li>serious parsing performances improvements</li> 1704</ul> 1705 1706<h3>2.3.2: Feb 24 2001</h3> 1707<ul> 1708 <li>chasing XPath bugs, found a bunch, completed some TODO</li> 1709 <li>fixed a Dtd parsing bug</li> 1710 <li>fixed a bug in xmlNodeGetContent</li> 1711 <li>ID/IDREF support partly rewritten by Gary Pennington</li> 1712</ul> 1713 1714<h3>2.3.1: Feb 15 2001</h3> 1715<ul> 1716 <li>some XPath and HTML bug fixes for XSLT</li> 1717 <li>small extension of the hash table interfaces for DOM gdome2 1718 implementation</li> 1719 <li>A few bug fixes</li> 1720</ul> 1721 1722<h3>2.3.0: Feb 8 2001 (2.2.12 was on 25 Jan but I didn't kept track)</h3> 1723<ul> 1724 <li>Lots of XPath bug fixes</li> 1725 <li>Add a mode with Dtd lookup but without validation error reporting for 1726 XSLT</li> 1727 <li>Add support for text node without escaping (XSLT)</li> 1728 <li>bug fixes for xmlCheckFilename</li> 1729 <li>validation code bug fixes from Gary Pennington</li> 1730 <li>Patch from Paul D. Smith correcting URI path normalization</li> 1731 <li>Patch to allow simultaneous install of libxml-devel and 1732 libxml2-devel</li> 1733 <li>the example Makefile is now fixed</li> 1734 <li>added HTML to the RPM packages</li> 1735 <li>tree copying bugfixes</li> 1736 <li>updates to Windows makefiles</li> 1737 <li>optimization patch from Bjorn Reese</li> 1738</ul> 1739 1740<h3>2.2.11: Jan 4 2001</h3> 1741<ul> 1742 <li>bunch of bug fixes (memory I/O, xpath, ftp/http, ...)</li> 1743 <li>added htmlHandleOmittedElem()</li> 1744 <li>Applied Bjorn Reese's IPV6 first patch</li> 1745 <li>Applied Paul D. Smith patches for validation of XInclude results</li> 1746 <li>added XPointer xmlns() new scheme support</li> 1747</ul> 1748 1749<h3>2.2.10: Nov 25 2000</h3> 1750<ul> 1751 <li>Fix the Windows problems of 2.2.8</li> 1752 <li>integrate OpenVMS patches</li> 1753 <li>better handling of some nasty HTML input</li> 1754 <li>Improved the XPointer implementation</li> 1755 <li>integrate a number of provided patches</li> 1756</ul> 1757 1758<h3>2.2.9: Nov 25 2000</h3> 1759<ul> 1760 <li>erroneous release :-(</li> 1761</ul> 1762 1763<h3>2.2.8: Nov 13 2000</h3> 1764<ul> 1765 <li>First version of <a href="http://www.w3.org/TR/xinclude">XInclude</a> 1766 support</li> 1767 <li>Patch in conditional section handling</li> 1768 <li>updated MS compiler project</li> 1769 <li>fixed some XPath problems</li> 1770 <li>added an URI escaping function</li> 1771 <li>some other bug fixes</li> 1772</ul> 1773 1774<h3>2.2.7: Oct 31 2000</h3> 1775<ul> 1776 <li>added message redirection</li> 1777 <li>XPath improvements (thanks TOM !)</li> 1778 <li>xmlIOParseDTD() added</li> 1779 <li>various small fixes in the HTML, URI, HTTP and XPointer support</li> 1780 <li>some cleanup of the Makefile, autoconf and the distribution content</li> 1781</ul> 1782 1783<h3>2.2.6: Oct 25 2000:</h3> 1784<ul> 1785 <li>Added an hash table module, migrated a number of internal structure to 1786 those</li> 1787 <li>Fixed a posteriori validation problems</li> 1788 <li>HTTP module cleanups</li> 1789 <li>HTML parser improvements (tag errors, script/style handling, attribute 1790 normalization)</li> 1791 <li>coalescing of adjacent text nodes</li> 1792 <li>couple of XPath bug fixes, exported the internal API</li> 1793</ul> 1794 1795<h3>2.2.5: Oct 15 2000:</h3> 1796<ul> 1797 <li>XPointer implementation and testsuite</li> 1798 <li>Lot of XPath fixes, added variable and functions registration, more 1799 tests</li> 1800 <li>Portability fixes, lots of enhancements toward an easy Windows build 1801 and release</li> 1802 <li>Late validation fixes</li> 1803 <li>Integrated a lot of contributed patches</li> 1804 <li>added memory management docs</li> 1805 <li>a performance problem when using large buffer seems fixed</li> 1806</ul> 1807 1808<h3>2.2.4: Oct 1 2000:</h3> 1809<ul> 1810 <li>main XPath problem fixed</li> 1811 <li>Integrated portability patches for Windows</li> 1812 <li>Serious bug fixes on the URI and HTML code</li> 1813</ul> 1814 1815<h3>2.2.3: Sep 17 2000</h3> 1816<ul> 1817 <li>bug fixes</li> 1818 <li>cleanup of entity handling code</li> 1819 <li>overall review of all loops in the parsers, all sprintf usage has been 1820 checked too</li> 1821 <li>Far better handling of larges Dtd. Validating against DocBook XML Dtd 1822 works smoothly now.</li> 1823</ul> 1824 1825<h3>1.8.10: Sep 6 2000</h3> 1826<ul> 1827 <li>bug fix release for some Gnome projects</li> 1828</ul> 1829 1830<h3>2.2.2: August 12 2000</h3> 1831<ul> 1832 <li>mostly bug fixes</li> 1833 <li>started adding routines to access xml parser context options</li> 1834</ul> 1835 1836<h3>2.2.1: July 21 2000</h3> 1837<ul> 1838 <li>a purely bug fixes release</li> 1839 <li>fixed an encoding support problem when parsing from a memory block</li> 1840 <li>fixed a DOCTYPE parsing problem</li> 1841 <li>removed a bug in the function allowing to override the memory 1842 allocation routines</li> 1843</ul> 1844 1845<h3>2.2.0: July 14 2000</h3> 1846<ul> 1847 <li>applied a lot of portability fixes</li> 1848 <li>better encoding support/cleanup and saving (content is now always 1849 encoded in UTF-8)</li> 1850 <li>the HTML parser now correctly handles encodings</li> 1851 <li>added xmlHasProp()</li> 1852 <li>fixed a serious problem with &#38;</li> 1853 <li>propagated the fix to FTP client</li> 1854 <li>cleanup, bugfixes, etc ...</li> 1855 <li>Added a page about <a href="encoding.html">libxml Internationalization 1856 support</a></li> 1857</ul> 1858 1859<h3>1.8.9: July 9 2000</h3> 1860<ul> 1861 <li>fixed the spec the RPMs should be better</li> 1862 <li>fixed a serious bug in the FTP implementation, released 1.8.9 to solve 1863 rpmfind users problem</li> 1864</ul> 1865 1866<h3>2.1.1: July 1 2000</h3> 1867<ul> 1868 <li>fixes a couple of bugs in the 2.1.0 packaging</li> 1869 <li>improvements on the HTML parser</li> 1870</ul> 1871 1872<h3>2.1.0 and 1.8.8: June 29 2000</h3> 1873<ul> 1874 <li>1.8.8 is mostly a commodity package for upgrading to libxml2 according 1875 to <a href="upgrade.html">new instructions</a>. It fixes a nasty problem 1876 about &#38; charref parsing</li> 1877 <li>2.1.0 also ease the upgrade from libxml v1 to the recent version. it 1878 also contains numerous fixes and enhancements: 1879 <ul> 1880 <li>added xmlStopParser() to stop parsing</li> 1881 <li>improved a lot parsing speed when there is large CDATA blocs</li> 1882 <li>includes XPath patches provided by Picdar Technology</li> 1883 <li>tried to fix as much as possible DTD validation and namespace 1884 related problems</li> 1885 <li>output to a given encoding has been added/tested</li> 1886 <li>lot of various fixes</li> 1887 </ul> 1888 </li> 1889</ul> 1890 1891<h3>2.0.0: Apr 12 2000</h3> 1892<ul> 1893 <li>First public release of libxml2. If you are using libxml, it's a good 1894 idea to check the 1.x to 2.x upgrade instructions. NOTE: while initially 1895 scheduled for Apr 3 the release occurred only on Apr 12 due to massive 1896 workload.</li> 1897 <li>The include are now located under $prefix/include/libxml (instead of 1898 $prefix/include/gnome-xml), they also are referenced by 1899 <pre>#include <libxml/xxx.h></pre> 1900 <p>instead of</p> 1901 <pre>#include "xxx.h"</pre> 1902 </li> 1903 <li>a new URI module for parsing URIs and following strictly RFC 2396</li> 1904 <li>the memory allocation routines used by libxml can now be overloaded 1905 dynamically by using xmlMemSetup()</li> 1906 <li>The previously CVS only tool tester has been renamed 1907 <strong>xmllint</strong> and is now installed as part of the libxml2 1908 package</li> 1909 <li>The I/O interface has been revamped. There is now ways to plug in 1910 specific I/O modules, either at the URI scheme detection level using 1911 xmlRegisterInputCallbacks() or by passing I/O functions when creating a 1912 parser context using xmlCreateIOParserCtxt()</li> 1913 <li>there is a C preprocessor macro LIBXML_VERSION providing the version 1914 number of the libxml module in use</li> 1915 <li>a number of optional features of libxml can now be excluded at 1916 configure time (FTP/HTTP/HTML/XPath/Debug)</li> 1917</ul> 1918 1919<h3>2.0.0beta: Mar 14 2000</h3> 1920<ul> 1921 <li>This is a first Beta release of libxml version 2</li> 1922 <li>It's available only from<a href="ftp://xmlsoft.org/">xmlsoft.org 1923 FTP</a>, it's packaged as libxml2-2.0.0beta and available as tar and 1924 RPMs</li> 1925 <li>This version is now the head in the Gnome CVS base, the old one is 1926 available under the tag LIB_XML_1_X</li> 1927 <li>This includes a very large set of changes. From a programmatic point 1928 of view applications should not have to be modified too much, check the 1929 <a href="upgrade.html">upgrade page</a></li> 1930 <li>Some interfaces may changes (especially a bit about encoding).</li> 1931 <li>the updates includes: 1932 <ul> 1933 <li>fix I18N support. ISO-Latin-x/UTF-8/UTF-16 (nearly) seems correctly 1934 handled now</li> 1935 <li>Better handling of entities, especially well-formedness checking 1936 and proper PEref extensions in external subsets</li> 1937 <li>DTD conditional sections</li> 1938 <li>Validation now correctly handle entities content</li> 1939 <li><a href="http://rpmfind.net/tools/gdome/messages/0039.html">change 1940 structures to accommodate DOM</a></li> 1941 </ul> 1942 </li> 1943 <li>Serious progress were made toward compliance, <a 1944 href="conf/result.html">here are the result of the test</a> against the 1945 OASIS testsuite (except the Japanese tests since I don't support that 1946 encoding yet). This URL is rebuilt every couple of hours using the CVS 1947 head version.</li> 1948</ul> 1949 1950<h3>1.8.7: Mar 6 2000</h3> 1951<ul> 1952 <li>This is a bug fix release:</li> 1953 <li>It is possible to disable the ignorable blanks heuristic used by 1954 libxml-1.x, a new function xmlKeepBlanksDefault(0) will allow this. Note 1955 that for adherence to XML spec, this behaviour will be disabled by 1956 default in 2.x . The same function will allow to keep compatibility for 1957 old code.</li> 1958 <li>Blanks in <a> </a> constructs are not ignored anymore, 1959 avoiding heuristic is really the Right Way :-\</li> 1960 <li>The unchecked use of snprintf which was breaking libxml-1.8.6 1961 compilation on some platforms has been fixed</li> 1962 <li>nanoftp.c nanohttp.c: Fixed '#' and '?' stripping when processing 1963 URIs</li> 1964</ul> 1965 1966<h3>1.8.6: Jan 31 2000</h3> 1967<ul> 1968 <li>added a nanoFTP transport module, debugged until the new version of <a 1969 href="http://rpmfind.net/linux/rpm2html/rpmfind.html">rpmfind</a> can use 1970 it without troubles</li> 1971</ul> 1972 1973<h3>1.8.5: Jan 21 2000</h3> 1974<ul> 1975 <li>adding APIs to parse a well balanced chunk of XML (production <a 1976 href="http://www.w3.org/TR/REC-xml#NT-content">[43] content</a> of the 1977 XML spec)</li> 1978 <li>fixed a hideous bug in xmlGetProp pointed by Rune.Djurhuus@fast.no</li> 1979 <li>Jody Goldberg <jgoldberg@home.com> provided another patch trying 1980 to solve the zlib checks problems</li> 1981 <li>The current state in gnome CVS base is expected to ship as 1.8.5 with 1982 gnumeric soon</li> 1983</ul> 1984 1985<h3>1.8.4: Jan 13 2000</h3> 1986<ul> 1987 <li>bug fixes, reintroduced xmlNewGlobalNs(), fixed xmlNewNs()</li> 1988 <li>all exit() call should have been removed from libxml</li> 1989 <li>fixed a problem with INCLUDE_WINSOCK on WIN32 platform</li> 1990 <li>added newDocFragment()</li> 1991</ul> 1992 1993<h3>1.8.3: Jan 5 2000</h3> 1994<ul> 1995 <li>a Push interface for the XML and HTML parsers</li> 1996 <li>a shell-like interface to the document tree (try tester --shell :-)</li> 1997 <li>lots of bug fixes and improvement added over XMas holidays</li> 1998 <li>fixed the DTD parsing code to work with the xhtml DTD</li> 1999 <li>added xmlRemoveProp(), xmlRemoveID() and xmlRemoveRef()</li> 2000 <li>Fixed bugs in xmlNewNs()</li> 2001 <li>External entity loading code has been revamped, now it uses 2002 xmlLoadExternalEntity(), some fix on entities processing were added</li> 2003 <li>cleaned up WIN32 includes of socket stuff</li> 2004</ul> 2005 2006<h3>1.8.2: Dec 21 1999</h3> 2007<ul> 2008 <li>I got another problem with includes and C++, I hope this issue is fixed 2009 for good this time</li> 2010 <li>Added a few tree modification functions: xmlReplaceNode, 2011 xmlAddPrevSibling, xmlAddNextSibling, xmlNodeSetName and 2012 xmlDocSetRootElement</li> 2013 <li>Tried to improve the HTML output with help from <a 2014 href="mailto:clahey@umich.edu">Chris Lahey</a></li> 2015</ul> 2016 2017<h3>1.8.1: Dec 18 1999</h3> 2018<ul> 2019 <li>various patches to avoid troubles when using libxml with C++ compilers 2020 the "namespace" keyword and C escaping in include files</li> 2021 <li>a problem in one of the core macros IS_CHAR was corrected</li> 2022 <li>fixed a bug introduced in 1.8.0 breaking default namespace processing, 2023 and more specifically the Dia application</li> 2024 <li>fixed a posteriori validation (validation after parsing, or by using a 2025 Dtd not specified in the original document)</li> 2026 <li>fixed a bug in</li> 2027</ul> 2028 2029<h3>1.8.0: Dec 12 1999</h3> 2030<ul> 2031 <li>cleanup, especially memory wise</li> 2032 <li>the parser should be more reliable, especially the HTML one, it should 2033 not crash, whatever the input !</li> 2034 <li>Integrated various patches, especially a speedup improvement for large 2035 dataset from <a href="mailto:cnygard@bellatlantic.net">Carl Nygard</a>, 2036 configure with --with-buffers to enable them.</li> 2037 <li>attribute normalization, oops should have been added long ago !</li> 2038 <li>attributes defaulted from DTDs should be available, xmlSetProp() now 2039 does entities escaping by default.</li> 2040</ul> 2041 2042<h3>1.7.4: Oct 25 1999</h3> 2043<ul> 2044 <li>Lots of HTML improvement</li> 2045 <li>Fixed some errors when saving both XML and HTML</li> 2046 <li>More examples, the regression tests should now look clean</li> 2047 <li>Fixed a bug with contiguous charref</li> 2048</ul> 2049 2050<h3>1.7.3: Sep 29 1999</h3> 2051<ul> 2052 <li>portability problems fixed</li> 2053 <li>snprintf was used unconditionally, leading to link problems on system 2054 were it's not available, fixed</li> 2055</ul> 2056 2057<h3>1.7.1: Sep 24 1999</h3> 2058<ul> 2059 <li>The basic type for strings manipulated by libxml has been renamed in 2060 1.7.1 from <strong>CHAR</strong> to <strong>xmlChar</strong>. The reason 2061 is that CHAR was conflicting with a predefined type on Windows. However 2062 on non WIN32 environment, compatibility is provided by the way of a 2063 <strong>#define </strong>.</li> 2064 <li>Changed another error : the use of a structure field called errno, and 2065 leading to troubles on platforms where it's a macro</li> 2066</ul> 2067 2068<h3>1.7.0: Sep 23 1999</h3> 2069<ul> 2070 <li>Added the ability to fetch remote DTD or parsed entities, see the <a 2071 href="html/libxml-nanohttp.html">nanohttp</a> module.</li> 2072 <li>Added an errno to report errors by another mean than a simple printf 2073 like callback</li> 2074 <li>Finished ID/IDREF support and checking when validation</li> 2075 <li>Serious memory leaks fixed (there is now a <a 2076 href="html/libxml-xmlmemory.html">memory wrapper</a> module)</li> 2077 <li>Improvement of <a href="http://www.w3.org/TR/xpath">XPath</a> 2078 implementation</li> 2079 <li>Added an HTML parser front-end</li> 2080</ul> 2081 2082<h2><a name="XML">XML</a></h2> 2083 2084<p><a href="http://www.w3.org/TR/REC-xml">XML is a standard</a> for 2085markup-based structured documents. Here is <a name="example">an example XML 2086document</a>:</p> 2087<pre><?xml version="1.0"?> 2088<EXAMPLE prop1="gnome is great" prop2="&amp; linux too"> 2089 <head> 2090 <title>Welcome to Gnome</title> 2091 </head> 2092 <chapter> 2093 <title>The Linux adventure</title> 2094 <p>bla bla bla ...</p> 2095 <image href="linus.gif"/> 2096 <p>...</p> 2097 </chapter> 2098</EXAMPLE></pre> 2099 2100<p>The first line specifies that it is an XML document and gives useful 2101information about its encoding. Then the rest of the document is a text 2102format whose structure is specified by tags between brackets. <strong>Each 2103tag opened has to be closed</strong>. XML is pedantic about this. However, if 2104a tag is empty (no content), a single tag can serve as both the opening and 2105closing tag if it ends with <code>/></code> rather than with 2106<code>></code>. Note that, for example, the image tag has no content (just 2107an attribute) and is closed by ending the tag with <code>/></code>.</p> 2108 2109<p>XML can be applied successfully to a wide range of tasks, ranging from 2110long term structured document maintenance (where it follows the steps of 2111SGML) to simple data encoding mechanisms like configuration file formatting 2112(glade), spreadsheets (gnumeric), or even shorter lived documents such as 2113WebDAV where it is used to encode remote calls between a client and a 2114server.</p> 2115 2116<h2><a name="XSLT">XSLT</a></h2> 2117 2118<p>Check <a href="http://xmlsoft.org/XSLT">the separate libxslt page</a></p> 2119 2120<p><a href="http://www.w3.org/TR/xslt">XSL Transformations</a>, is a 2121language for transforming XML documents into other XML documents (or 2122HTML/textual output).</p> 2123 2124<p>A separate library called libxslt is available implementing XSLT-1.0 for 2125libxml2. This module "libxslt" too can be found in the Gnome CVS base.</p> 2126 2127<p>You can check the <a 2128href="http://cvs.gnome.org/lxr/source/libxslt/FEATURES">features</a> 2129supported and the progresses on the <a 2130href="http://cvs.gnome.org/lxr/source/libxslt/ChangeLog" 2131name="Changelog">Changelog</a>.</p> 2132 2133<h2><a name="Python">Python and bindings</a></h2> 2134 2135<p>There are a number of language bindings and wrappers available for 2136libxml2, the list below is not exhaustive. Please contact the <a 2137href="http://mail.gnome.org/mailman/listinfo/xml-bindings">xml-bindings@gnome.org</a> 2138(<a href="http://mail.gnome.org/archives/xml-bindings/">archives</a>) in 2139order to get updates to this list or to discuss the specific topic of libxml2 2140or libxslt wrappers or bindings:</p> 2141<ul> 2142 <li><a href="http://libxmlplusplus.sourceforge.net/">Libxml++</a> seems the 2143 most up-to-date C++ bindings for libxml2, check the <a 2144 href="http://libxmlplusplus.sourceforge.net/reference/html/hierarchy.html">documentation</a> 2145 and the <a 2146 href="http://cvs.sourceforge.net/cgi-bin/viewcvs.cgi/libxmlplusplus/libxml%2b%2b/examples/">examples</a>.</li> 2147 <li>There is another <a href="http://libgdome-cpp.berlios.de/">C++ wrapper 2148 based on the gdome2 bindings</a> maintained by Tobias Peters.</li> 2149 <li>and a third C++ wrapper by Peter Jones <pjones@pmade.org> 2150 <p>Website: <a 2151 href="http://pmade.org/pjones/software/xmlwrapp/">http://pmade.org/pjones/software/xmlwrapp/</a></p> 2152 </li> 2153 <li><a 2154 href="http://mail.gnome.org/archives/xml/2001-March/msg00014.html">Matt 2155 Sergeant</a> developed <a 2156 href="http://axkit.org/download/">XML::LibXSLT</a>, a Perl wrapper for 2157 libxml2/libxslt as part of the <a href="http://axkit.com/">AxKit XML 2158 application server</a>.</li> 2159 <li>If you're interested into scripting XML processing, have a look at <a 2160 href="http://xsh.sourceforge.net/">XSH</a> an XML editing shell based on 2161 Libxml2 Perl bindings.</li> 2162 <li><a href="mailto:dkuhlman@cutter.rexx.com">Dave Kuhlman</a> provides an 2163 earlier version of the libxml/libxslt <a 2164 href="http://www.rexx.com/~dkuhlman">wrappers for Python</a>.</li> 2165 <li>Gopal.V and Peter Minten develop <a 2166 href="http://savannah.gnu.org/projects/libxmlsharp">libxml#</a>, a set of 2167 C# libxml2 bindings.</li> 2168 <li>Petr Kozelka provides <a 2169 href="http://sourceforge.net/projects/libxml2-pas">Pascal units to glue 2170 libxml2</a> with Kylix, Delphi and other Pascal compilers.</li> 2171 <li>Uwe Fechner also provides <a 2172 href="http://sourceforge.net/projects/idom2-pas/">idom2</a>, a DOM2 2173 implementation for Kylix2/D5/D6 from Borland.</li> 2174 <li>Wai-Sun "Squidster" Chia provides <a 2175 href="http://www.rubycolor.org/arc/redist/">bindings for Ruby</a> and 2176 libxml2 bindings are also available in Ruby through the <a 2177 href="http://libgdome-ruby.berlios.de/">libgdome-ruby</a> module 2178 maintained by Tobias Peters.</li> 2179 <li>Steve Ball and contributors maintains <a 2180 href="http://tclxml.sourceforge.net/">libxml2 and libxslt bindings for 2181 Tcl</a>.</li> 2182 <li>There is support for libxml2 in the DOM module of PHP.</li> 2183 <li><a href="http://savannah.gnu.org/projects/classpathx/">LibxmlJ</a> is 2184 an effort to create a 100% JAXP-compatible Java wrapper for libxml2 and 2185 libxslt as part of GNU ClasspathX project.</li> 2186 <li>Patrick McPhee provides Rexx bindings fof libxml2 and libxslt, look for 2187 <a href="http://www.interlog.com/~ptjm/software.html">RexxXML</a>.</li> 2188</ul> 2189 2190<p>The distribution includes a set of Python bindings, which are guaranteed 2191to be maintained as part of the library in the future, though the Python 2192interface have not yet reached the completeness of the C API.</p> 2193 2194<p><a href="mailto:stephane.bidoul@softwareag.com">St�phane Bidoul</a> 2195maintains <a href="http://users.skynet.be/sbi/libxml-python/">a Windows port 2196of the Python bindings</a>.</p> 2197 2198<p>Note to people interested in building bindings, the API is formalized as 2199<a href="libxml2-api.xml">an XML API description file</a> which allows to 2200automate a large part of the Python bindings, this includes function 2201descriptions, enums, structures, typedefs, etc... The Python script used to 2202build the bindings is python/generator.py in the source distribution.</p> 2203 2204<p>To install the Python bindings there are 2 options:</p> 2205<ul> 2206 <li>If you use an RPM based distribution, simply install the <a 2207 href="http://rpmfind.net/linux/rpm2html/search.php?query=libxml2-python">libxml2-python 2208 RPM</a> (and if needed the <a 2209 href="http://rpmfind.net/linux/rpm2html/search.php?query=libxslt-python">libxslt-python 2210 RPM</a>).</li> 2211 <li>Otherwise use the <a href="ftp://xmlsoft.org/python/">libxml2-python 2212 module distribution</a> corresponding to your installed version of 2213 libxml2 and libxslt. Note that to install it you will need both libxml2 2214 and libxslt installed and run "python setup.py build install" in the 2215 module tree.</li> 2216</ul> 2217 2218<p>The distribution includes a set of examples and regression tests for the 2219python bindings in the <code>python/tests</code> directory. Here are some 2220excerpts from those tests:</p> 2221 2222<h3>tst.py:</h3> 2223 2224<p>This is a basic test of the file interface and DOM navigation:</p> 2225<pre>import libxml2, sys 2226 2227doc = libxml2.parseFile("tst.xml") 2228if doc.name != "tst.xml": 2229 print "doc.name failed" 2230 sys.exit(1) 2231root = doc.children 2232if root.name != "doc": 2233 print "root.name failed" 2234 sys.exit(1) 2235child = root.children 2236if child.name != "foo": 2237 print "child.name failed" 2238 sys.exit(1) 2239doc.freeDoc()</pre> 2240 2241<p>The Python module is called libxml2; parseFile is the equivalent of 2242xmlParseFile (most of the bindings are automatically generated, and the xml 2243prefix is removed and the casing convention are kept). All node seen at the 2244binding level share the same subset of accessors:</p> 2245<ul> 2246 <li><code>name</code> : returns the node name</li> 2247 <li><code>type</code> : returns a string indicating the node type</li> 2248 <li><code>content</code> : returns the content of the node, it is based on 2249 xmlNodeGetContent() and hence is recursive.</li> 2250 <li><code>parent</code> , <code>children</code>, <code>last</code>, 2251 <code>next</code>, <code>prev</code>, <code>doc</code>, 2252 <code>properties</code>: pointing to the associated element in the tree, 2253 those may return None in case no such link exists.</li> 2254</ul> 2255 2256<p>Also note the need to explicitly deallocate documents with freeDoc() . 2257Reference counting for libxml2 trees would need quite a lot of work to 2258function properly, and rather than risk memory leaks if not implemented 2259correctly it sounds safer to have an explicit function to free a tree. The 2260wrapper python objects like doc, root or child are them automatically garbage 2261collected.</p> 2262 2263<h3>validate.py:</h3> 2264 2265<p>This test check the validation interfaces and redirection of error 2266messages:</p> 2267<pre>import libxml2 2268 2269#deactivate error messages from the validation 2270def noerr(ctx, str): 2271 pass 2272 2273libxml2.registerErrorHandler(noerr, None) 2274 2275ctxt = libxml2.createFileParserCtxt("invalid.xml") 2276ctxt.validate(1) 2277ctxt.parseDocument() 2278doc = ctxt.doc() 2279valid = ctxt.isValid() 2280doc.freeDoc() 2281if valid != 0: 2282 print "validity check failed"</pre> 2283 2284<p>The first thing to notice is the call to registerErrorHandler(), it 2285defines a new error handler global to the library. It is used to avoid seeing 2286the error messages when trying to validate the invalid document.</p> 2287 2288<p>The main interest of that test is the creation of a parser context with 2289createFileParserCtxt() and how the behaviour can be changed before calling 2290parseDocument() . Similarly the informations resulting from the parsing phase 2291are also available using context methods.</p> 2292 2293<p>Contexts like nodes are defined as class and the libxml2 wrappers maps the 2294C function interfaces in terms of objects method as much as possible. The 2295best to get a complete view of what methods are supported is to look at the 2296libxml2.py module containing all the wrappers.</p> 2297 2298<h3>push.py:</h3> 2299 2300<p>This test show how to activate the push parser interface:</p> 2301<pre>import libxml2 2302 2303ctxt = libxml2.createPushParser(None, "<foo", 4, "test.xml") 2304ctxt.parseChunk("/>", 2, 1) 2305doc = ctxt.doc() 2306 2307doc.freeDoc()</pre> 2308 2309<p>The context is created with a special call based on the 2310xmlCreatePushParser() from the C library. The first argument is an optional 2311SAX callback object, then the initial set of data, the length and the name of 2312the resource in case URI-References need to be computed by the parser.</p> 2313 2314<p>Then the data are pushed using the parseChunk() method, the last call 2315setting the third argument terminate to 1.</p> 2316 2317<h3>pushSAX.py:</h3> 2318 2319<p>this test show the use of the event based parsing interfaces. In this case 2320the parser does not build a document, but provides callback information as 2321the parser makes progresses analyzing the data being provided:</p> 2322<pre>import libxml2 2323log = "" 2324 2325class callback: 2326 def startDocument(self): 2327 global log 2328 log = log + "startDocument:" 2329 2330 def endDocument(self): 2331 global log 2332 log = log + "endDocument:" 2333 2334 def startElement(self, tag, attrs): 2335 global log 2336 log = log + "startElement %s %s:" % (tag, attrs) 2337 2338 def endElement(self, tag): 2339 global log 2340 log = log + "endElement %s:" % (tag) 2341 2342 def characters(self, data): 2343 global log 2344 log = log + "characters: %s:" % (data) 2345 2346 def warning(self, msg): 2347 global log 2348 log = log + "warning: %s:" % (msg) 2349 2350 def error(self, msg): 2351 global log 2352 log = log + "error: %s:" % (msg) 2353 2354 def fatalError(self, msg): 2355 global log 2356 log = log + "fatalError: %s:" % (msg) 2357 2358handler = callback() 2359 2360ctxt = libxml2.createPushParser(handler, "<foo", 4, "test.xml") 2361chunk = " url='tst'>b" 2362ctxt.parseChunk(chunk, len(chunk), 0) 2363chunk = "ar</foo>" 2364ctxt.parseChunk(chunk, len(chunk), 1) 2365 2366reference = "startDocument:startElement foo {'url': 'tst'}:" + \ 2367 "characters: bar:endElement foo:endDocument:" 2368if log != reference: 2369 print "Error got: %s" % log 2370 print "Expected: %s" % reference</pre> 2371 2372<p>The key object in that test is the handler, it provides a number of entry 2373points which can be called by the parser as it makes progresses to indicate 2374the information set obtained. The full set of callback is larger than what 2375the callback class in that specific example implements (see the SAX 2376definition for a complete list). The wrapper will only call those supplied by 2377the object when activated. The startElement receives the names of the element 2378and a dictionary containing the attributes carried by this element.</p> 2379 2380<p>Also note that the reference string generated from the callback shows a 2381single character call even though the string "bar" is passed to the parser 2382from 2 different call to parseChunk()</p> 2383 2384<h3>xpath.py:</h3> 2385 2386<p>This is a basic test of XPath wrappers support</p> 2387<pre>import libxml2 2388 2389doc = libxml2.parseFile("tst.xml") 2390ctxt = doc.xpathNewContext() 2391res = ctxt.xpathEval("//*") 2392if len(res) != 2: 2393 print "xpath query: wrong node set size" 2394 sys.exit(1) 2395if res[0].name != "doc" or res[1].name != "foo": 2396 print "xpath query: wrong node set value" 2397 sys.exit(1) 2398doc.freeDoc() 2399ctxt.xpathFreeContext()</pre> 2400 2401<p>This test parses a file, then create an XPath context to evaluate XPath 2402expression on it. The xpathEval() method execute an XPath query and returns 2403the result mapped in a Python way. String and numbers are natively converted, 2404and node sets are returned as a tuple of libxml2 Python nodes wrappers. Like 2405the document, the XPath context need to be freed explicitly, also not that 2406the result of the XPath query may point back to the document tree and hence 2407the document must be freed after the result of the query is used.</p> 2408 2409<h3>xpathext.py:</h3> 2410 2411<p>This test shows how to extend the XPath engine with functions written in 2412python:</p> 2413<pre>import libxml2 2414 2415def foo(ctx, x): 2416 return x + 1 2417 2418doc = libxml2.parseFile("tst.xml") 2419ctxt = doc.xpathNewContext() 2420libxml2.registerXPathFunction(ctxt._o, "foo", None, foo) 2421res = ctxt.xpathEval("foo(1)") 2422if res != 2: 2423 print "xpath extension failure" 2424doc.freeDoc() 2425ctxt.xpathFreeContext()</pre> 2426 2427<p>Note how the extension function is registered with the context (but that 2428part is not yet finalized, this may change slightly in the future).</p> 2429 2430<h3>tstxpath.py:</h3> 2431 2432<p>This test is similar to the previous one but shows how the extension 2433function can access the XPath evaluation context:</p> 2434<pre>def foo(ctx, x): 2435 global called 2436 2437 # 2438 # test that access to the XPath evaluation contexts 2439 # 2440 pctxt = libxml2.xpathParserContext(_obj=ctx) 2441 ctxt = pctxt.context() 2442 called = ctxt.function() 2443 return x + 1</pre> 2444 2445<p>All the interfaces around the XPath parser(or rather evaluation) context 2446are not finalized, but it should be sufficient to do contextual work at the 2447evaluation point.</p> 2448 2449<h3>Memory debugging:</h3> 2450 2451<p>last but not least, all tests starts with the following prologue:</p> 2452<pre>#memory debug specific 2453libxml2.debugMemory(1)</pre> 2454 2455<p>and ends with the following epilogue:</p> 2456<pre>#memory debug specific 2457libxml2.cleanupParser() 2458if libxml2.debugMemory(1) == 0: 2459 print "OK" 2460else: 2461 print "Memory leak %d bytes" % (libxml2.debugMemory(1)) 2462 libxml2.dumpMemory()</pre> 2463 2464<p>Those activate the memory debugging interface of libxml2 where all 2465allocated block in the library are tracked. The prologue then cleans up the 2466library state and checks that all allocated memory has been freed. If not it 2467calls dumpMemory() which saves that list in a <code>.memdump</code> file.</p> 2468 2469<h2><a name="architecture">libxml2 architecture</a></h2> 2470 2471<p>Libxml2 is made of multiple components; some of them are optional, and 2472most of the block interfaces are public. The main components are:</p> 2473<ul> 2474 <li>an Input/Output layer</li> 2475 <li>FTP and HTTP client layers (optional)</li> 2476 <li>an Internationalization layer managing the encodings support</li> 2477 <li>a URI module</li> 2478 <li>the XML parser and its basic SAX interface</li> 2479 <li>an HTML parser using the same SAX interface (optional)</li> 2480 <li>a SAX tree module to build an in-memory DOM representation</li> 2481 <li>a tree module to manipulate the DOM representation</li> 2482 <li>a validation module using the DOM representation (optional)</li> 2483 <li>an XPath module for global lookup in a DOM representation 2484 (optional)</li> 2485 <li>a debug module (optional)</li> 2486</ul> 2487 2488<p>Graphically this gives the following:</p> 2489 2490<p><img src="libxml.gif" alt="a graphical view of the various"></p> 2491 2492<p></p> 2493 2494<h2><a name="tree">The tree output</a></h2> 2495 2496<p>The parser returns a tree built during the document analysis. The value 2497returned is an <strong>xmlDocPtr</strong> (i.e., a pointer to an 2498<strong>xmlDoc</strong> structure). This structure contains information such 2499as the file name, the document type, and a <strong>children</strong> pointer 2500which is the root of the document (or more exactly the first child under the 2501root which is the document). The tree is made of <strong>xmlNode</strong>s, 2502chained in double-linked lists of siblings and with a children<->parent 2503relationship. An xmlNode can also carry properties (a chain of xmlAttr 2504structures). An attribute may have a value which is a list of TEXT or 2505ENTITY_REF nodes.</p> 2506 2507<p>Here is an example (erroneous with respect to the XML spec since there 2508should be only one ELEMENT under the root):</p> 2509 2510<p><img src="structure.gif" alt=" structure.gif "></p> 2511 2512<p>In the source package there is a small program (not installed by default) 2513called <strong>xmllint</strong> which parses XML files given as argument and 2514prints them back as parsed. This is useful for detecting errors both in XML 2515code and in the XML parser itself. It has an option <strong>--debug</strong> 2516which prints the actual in-memory structure of the document; here is the 2517result with the <a href="#example">example</a> given before:</p> 2518<pre>DOCUMENT 2519version=1.0 2520standalone=true 2521 ELEMENT EXAMPLE 2522 ATTRIBUTE prop1 2523 TEXT 2524 content=gnome is great 2525 ATTRIBUTE prop2 2526 ENTITY_REF 2527 TEXT 2528 content= linux too 2529 ELEMENT head 2530 ELEMENT title 2531 TEXT 2532 content=Welcome to Gnome 2533 ELEMENT chapter 2534 ELEMENT title 2535 TEXT 2536 content=The Linux adventure 2537 ELEMENT p 2538 TEXT 2539 content=bla bla bla ... 2540 ELEMENT image 2541 ATTRIBUTE href 2542 TEXT 2543 content=linus.gif 2544 ELEMENT p 2545 TEXT 2546 content=...</pre> 2547 2548<p>This should be useful for learning the internal representation model.</p> 2549 2550<h2><a name="interface">The SAX interface</a></h2> 2551 2552<p>Sometimes the DOM tree output is just too large to fit reasonably into 2553memory. In that case (and if you don't expect to save back the XML document 2554loaded using libxml), it's better to use the SAX interface of libxml. SAX is 2555a <strong>callback-based interface</strong> to the parser. Before parsing, 2556the application layer registers a customized set of callbacks which are 2557called by the library as it progresses through the XML input.</p> 2558 2559<p>To get more detailed step-by-step guidance on using the SAX interface of 2560libxml, see the <a 2561href="http://www.daa.com.au/~james/gnome/xml-sax/xml-sax.html">nice 2562documentation</a>.written by <a href="mailto:james@daa.com.au">James 2563Henstridge</a>.</p> 2564 2565<p>You can debug the SAX behaviour by using the <strong>testSAX</strong> 2566program located in the gnome-xml module (it's usually not shipped in the 2567binary packages of libxml, but you can find it in the tar source 2568distribution). Here is the sequence of callbacks that would be reported by 2569testSAX when parsing the example XML document shown earlier:</p> 2570<pre>SAX.setDocumentLocator() 2571SAX.startDocument() 2572SAX.getEntity(amp) 2573SAX.startElement(EXAMPLE, prop1='gnome is great', prop2='&amp; linux too') 2574SAX.characters( , 3) 2575SAX.startElement(head) 2576SAX.characters( , 4) 2577SAX.startElement(title) 2578SAX.characters(Welcome to Gnome, 16) 2579SAX.endElement(title) 2580SAX.characters( , 3) 2581SAX.endElement(head) 2582SAX.characters( , 3) 2583SAX.startElement(chapter) 2584SAX.characters( , 4) 2585SAX.startElement(title) 2586SAX.characters(The Linux adventure, 19) 2587SAX.endElement(title) 2588SAX.characters( , 4) 2589SAX.startElement(p) 2590SAX.characters(bla bla bla ..., 15) 2591SAX.endElement(p) 2592SAX.characters( , 4) 2593SAX.startElement(image, href='linus.gif') 2594SAX.endElement(image) 2595SAX.characters( , 4) 2596SAX.startElement(p) 2597SAX.characters(..., 3) 2598SAX.endElement(p) 2599SAX.characters( , 3) 2600SAX.endElement(chapter) 2601SAX.characters( , 1) 2602SAX.endElement(EXAMPLE) 2603SAX.endDocument()</pre> 2604 2605<p>Most of the other interfaces of libxml2 are based on the DOM tree-building 2606facility, so nearly everything up to the end of this document presupposes the 2607use of the standard DOM tree build. Note that the DOM tree itself is built by 2608a set of registered default callbacks, without internal specific 2609interface.</p> 2610 2611<h2><a name="Validation">Validation & DTDs</a></h2> 2612 2613<p>Table of Content:</p> 2614<ol> 2615 <li><a href="#General5">General overview</a></li> 2616 <li><a href="#definition">The definition</a></li> 2617 <li><a href="#Simple">Simple rules</a> 2618 <ol> 2619 <li><a href="#reference">How to reference a DTD from a document</a></li> 2620 <li><a href="#Declaring">Declaring elements</a></li> 2621 <li><a href="#Declaring1">Declaring attributes</a></li> 2622 </ol> 2623 </li> 2624 <li><a href="#Some">Some examples</a></li> 2625 <li><a href="#validate">How to validate</a></li> 2626 <li><a href="#Other">Other resources</a></li> 2627</ol> 2628 2629<h3><a name="General5">General overview</a></h3> 2630 2631<p>Well what is validation and what is a DTD ?</p> 2632 2633<p>DTD is the acronym for Document Type Definition. This is a description of 2634the content for a family of XML files. This is part of the XML 1.0 2635specification, and allows one to describe and verify that a given document 2636instance conforms to the set of rules detailing its structure and content.</p> 2637 2638<p>Validation is the process of checking a document against a DTD (more 2639generally against a set of construction rules).</p> 2640 2641<p>The validation process and building DTDs are the two most difficult parts 2642of the XML life cycle. Briefly a DTD defines all the possible elements to be 2643found within your document, what is the formal shape of your document tree 2644(by defining the allowed content of an element; either text, a regular 2645expression for the allowed list of children, or mixed content i.e. both text 2646and children). The DTD also defines the valid attributes for all elements and 2647the types of those attributes.</p> 2648 2649<h3><a name="definition1">The definition</a></h3> 2650 2651<p>The <a href="http://www.w3.org/TR/REC-xml">W3C XML Recommendation</a> (<a 2652href="http://www.xml.com/axml/axml.html">Tim Bray's annotated version of 2653Rev1</a>):</p> 2654<ul> 2655 <li><a href="http://www.w3.org/TR/REC-xml#elemdecls">Declaring 2656 elements</a></li> 2657 <li><a href="http://www.w3.org/TR/REC-xml#attdecls">Declaring 2658 attributes</a></li> 2659</ul> 2660 2661<p>(unfortunately) all this is inherited from the SGML world, the syntax is 2662ancient...</p> 2663 2664<h3><a name="Simple1">Simple rules</a></h3> 2665 2666<p>Writing DTDs can be done in many ways. The rules to build them if you need 2667something permanent or something which can evolve over time can be radically 2668different. Really complex DTDs like DocBook ones are flexible but quite 2669harder to design. I will just focus on DTDs for a formats with a fixed simple 2670structure. It is just a set of basic rules, and definitely not exhaustive nor 2671usable for complex DTD design.</p> 2672 2673<h4><a name="reference1">How to reference a DTD from a document</a>:</h4> 2674 2675<p>Assuming the top element of the document is <code>spec</code> and the dtd 2676is placed in the file <code>mydtd</code> in the subdirectory 2677<code>dtds</code> of the directory from where the document were loaded:</p> 2678 2679<p><code><!DOCTYPE spec SYSTEM "dtds/mydtd"></code></p> 2680 2681<p>Notes:</p> 2682<ul> 2683 <li>The system string is actually an URI-Reference (as defined in <a 2684 href="http://www.ietf.org/rfc/rfc2396.txt">RFC 2396</a>) so you can use a 2685 full URL string indicating the location of your DTD on the Web. This is a 2686 really good thing to do if you want others to validate your document.</li> 2687 <li>It is also possible to associate a <code>PUBLIC</code> identifier (a 2688 magic string) so that the DTD is looked up in catalogs on the client side 2689 without having to locate it on the web.</li> 2690 <li>A DTD contains a set of element and attribute declarations, but they 2691 don't define what the root of the document should be. This is explicitly 2692 told to the parser/validator as the first element of the 2693 <code>DOCTYPE</code> declaration.</li> 2694</ul> 2695 2696<h4><a name="Declaring2">Declaring elements</a>:</h4> 2697 2698<p>The following declares an element <code>spec</code>:</p> 2699 2700<p><code><!ELEMENT spec (front, body, back?)></code></p> 2701 2702<p>It also expresses that the spec element contains one <code>front</code>, 2703one <code>body</code> and one optional <code>back</code> children elements in 2704this order. The declaration of one element of the structure and its content 2705are done in a single declaration. Similarly the following declares 2706<code>div1</code> elements:</p> 2707 2708<p><code><!ELEMENT div1 (head, (p | list | note)*, div2?)></code></p> 2709 2710<p>which means div1 contains one <code>head</code> then a series of optional 2711<code>p</code>, <code>list</code>s and <code>note</code>s and then an 2712optional <code>div2</code>. And last but not least an element can contain 2713text:</p> 2714 2715<p><code><!ELEMENT b (#PCDATA)></code></p> 2716 2717<p><code>b</code> contains text or being of mixed content (text and elements 2718in no particular order):</p> 2719 2720<p><code><!ELEMENT p (#PCDATA|a|ul|b|i|em)*></code></p> 2721 2722<p><code>p </code>can contain text or <code>a</code>, <code>ul</code>, 2723<code>b</code>, <code>i </code>or <code>em</code> elements in no particular 2724order.</p> 2725 2726<h4><a name="Declaring1">Declaring attributes</a>:</h4> 2727 2728<p>Again the attributes declaration includes their content definition:</p> 2729 2730<p><code><!ATTLIST termdef name CDATA #IMPLIED></code></p> 2731 2732<p>means that the element <code>termdef</code> can have a <code>name</code> 2733attribute containing text (<code>CDATA</code>) and which is optional 2734(<code>#IMPLIED</code>). The attribute value can also be defined within a 2735set:</p> 2736 2737<p><code><!ATTLIST list type (bullets|ordered|glossary) 2738"ordered"></code></p> 2739 2740<p>means <code>list</code> element have a <code>type</code> attribute with 3 2741allowed values "bullets", "ordered" or "glossary" and which default to 2742"ordered" if the attribute is not explicitly specified.</p> 2743 2744<p>The content type of an attribute can be text (<code>CDATA</code>), 2745anchor/reference/references 2746(<code>ID</code>/<code>IDREF</code>/<code>IDREFS</code>), entity(ies) 2747(<code>ENTITY</code>/<code>ENTITIES</code>) or name(s) 2748(<code>NMTOKEN</code>/<code>NMTOKENS</code>). The following defines that a 2749<code>chapter</code> element can have an optional <code>id</code> attribute 2750of type <code>ID</code>, usable for reference from attribute of type 2751IDREF:</p> 2752 2753<p><code><!ATTLIST chapter id ID #IMPLIED></code></p> 2754 2755<p>The last value of an attribute definition can be <code>#REQUIRED 2756</code>meaning that the attribute has to be given, <code>#IMPLIED</code> 2757meaning that it is optional, or the default value (possibly prefixed by 2758<code>#FIXED</code> if it is the only allowed).</p> 2759 2760<p>Notes:</p> 2761<ul> 2762 <li>Usually the attributes pertaining to a given element are declared in a 2763 single expression, but it is just a convention adopted by a lot of DTD 2764 writers: 2765 <pre><!ATTLIST termdef 2766 id ID #REQUIRED 2767 name CDATA #IMPLIED></pre> 2768 <p>The previous construct defines both <code>id</code> and 2769 <code>name</code> attributes for the element <code>termdef</code>.</p> 2770 </li> 2771</ul> 2772 2773<h3><a name="Some1">Some examples</a></h3> 2774 2775<p>The directory <code>test/valid/dtds/</code> in the libxml2 distribution 2776contains some complex DTD examples. The example in the file 2777<code>test/valid/dia.xml</code> shows an XML file where the simple DTD is 2778directly included within the document.</p> 2779 2780<h3><a name="validate1">How to validate</a></h3> 2781 2782<p>The simplest way is to use the xmllint program included with libxml. The 2783<code>--valid</code> option turns-on validation of the files given as input. 2784For example the following validates a copy of the first revision of the XML 27851.0 specification:</p> 2786 2787<p><code>xmllint --valid --noout test/valid/REC-xml-19980210.xml</code></p> 2788 2789<p>the -- noout is used to disable output of the resulting tree.</p> 2790 2791<p>The <code>--dtdvalid dtd</code> allows validation of the document(s) 2792against a given DTD.</p> 2793 2794<p>Libxml2 exports an API to handle DTDs and validation, check the <a 2795href="http://xmlsoft.org/html/libxml-valid.html">associated 2796description</a>.</p> 2797 2798<h3><a name="Other1">Other resources</a></h3> 2799 2800<p>DTDs are as old as SGML. So there may be a number of examples on-line, I 2801will just list one for now, others pointers welcome:</p> 2802<ul> 2803 <li><a href="http://www.xml101.com:8081/dtd/">XML-101 DTD</a></li> 2804</ul> 2805 2806<p>I suggest looking at the examples found under test/valid/dtd and any of 2807the large number of books available on XML. The dia example in test/valid 2808should be both simple and complete enough to allow you to build your own.</p> 2809 2810<p></p> 2811 2812<h2><a name="Memory">Memory Management</a></h2> 2813 2814<p>Table of Content:</p> 2815<ol> 2816 <li><a href="#General3">General overview</a></li> 2817 <li><a href="#setting">Setting libxml2 set of memory routines</a></li> 2818 <li><a href="#cleanup">Cleaning up after parsing</a></li> 2819 <li><a href="#Debugging">Debugging routines</a></li> 2820 <li><a href="#General4">General memory requirements</a></li> 2821</ol> 2822 2823<h3><a name="General3">General overview</a></h3> 2824 2825<p>The module <code><a 2826href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlmemory.h</a></code> 2827provides the interfaces to the libxml2 memory system:</p> 2828<ul> 2829 <li>libxml2 does not use the libc memory allocator directly but xmlFree(), 2830 xmlMalloc() and xmlRealloc()</li> 2831 <li>those routines can be reallocated to a specific set of routine, by 2832 default the libc ones i.e. free(), malloc() and realloc()</li> 2833 <li>the xmlmemory.c module includes a set of debugging routine</li> 2834</ul> 2835 2836<h3><a name="setting">Setting libxml2 set of memory routines</a></h3> 2837 2838<p>It is sometimes useful to not use the default memory allocator, either for 2839debugging, analysis or to implement a specific behaviour on memory management 2840(like on embedded systems). Two function calls are available to do so:</p> 2841<ul> 2842 <li><a href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlMemGet 2843 ()</a> which return the current set of functions in use by the parser</li> 2844 <li><a 2845 href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlMemSetup()</a> 2846 which allow to set up a new set of memory allocation functions</li> 2847</ul> 2848 2849<p>Of course a call to xmlMemSetup() should probably be done before calling 2850any other libxml2 routines (unless you are sure your allocations routines are 2851compatibles).</p> 2852 2853<h3><a name="cleanup">Cleaning up after parsing</a></h3> 2854 2855<p>Libxml2 is not stateless, there is a few set of memory structures needing 2856allocation before the parser is fully functional (some encoding structures 2857for example). This also mean that once parsing is finished there is a tiny 2858amount of memory (a few hundred bytes) which can be recollected if you don't 2859reuse the parser immediately:</p> 2860<ul> 2861 <li><a href="http://xmlsoft.org/html/libxml-parser.html">xmlCleanupParser 2862 ()</a> is a centralized routine to free the parsing states. Note that it 2863 won't deallocate any produced tree if any (use the xmlFreeDoc() and 2864 related routines for this).</li> 2865 <li><a href="http://xmlsoft.org/html/libxml-parser.html">xmlInitParser 2866 ()</a> is the dual routine allowing to preallocate the parsing state 2867 which can be useful for example to avoid initialization reentrancy 2868 problems when using libxml2 in multithreaded applications</li> 2869</ul> 2870 2871<p>Generally xmlCleanupParser() is safe, if needed the state will be rebuild 2872at the next invocation of parser routines, but be careful of the consequences 2873in multithreaded applications.</p> 2874 2875<h3><a name="Debugging">Debugging routines</a></h3> 2876 2877<p>When configured using --with-mem-debug flag (off by default), libxml2 uses 2878a set of memory allocation debugging routines keeping track of all allocated 2879blocks and the location in the code where the routine was called. A couple of 2880other debugging routines allow to dump the memory allocated infos to a file 2881or call a specific routine when a given block number is allocated:</p> 2882<ul> 2883 <li><a 2884 href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlMallocLoc()</a> 2885 <a 2886 href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlReallocLoc()</a> 2887 and <a 2888 href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlMemStrdupLoc()</a> 2889 are the memory debugging replacement allocation routines</li> 2890 <li><a href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlMemoryDump 2891 ()</a> dumps all the informations about the allocated memory block lefts 2892 in the <code>.memdump</code> file</li> 2893</ul> 2894 2895<p>When developing libxml2 memory debug is enabled, the tests programs call 2896xmlMemoryDump () and the "make test" regression tests will check for any 2897memory leak during the full regression test sequence, this helps a lot 2898ensuring that libxml2 does not leak memory and bullet proof memory 2899allocations use (some libc implementations are known to be far too permissive 2900resulting in major portability problems!).</p> 2901 2902<p>If the .memdump reports a leak, it displays the allocation function and 2903also tries to give some informations about the content and structure of the 2904allocated blocks left. This is sufficient in most cases to find the culprit, 2905but not always. Assuming the allocation problem is reproducible, it is 2906possible to find more easily:</p> 2907<ol> 2908 <li>write down the block number xxxx not allocated</li> 2909 <li>export the environment variable XML_MEM_BREAKPOINT=xxxx , the easiest 2910 when using GDB is to simply give the command 2911 <p><code>set environment XML_MEM_BREAKPOINT xxxx</code></p> 2912 <p>before running the program.</p> 2913 </li> 2914 <li>run the program under a debugger and set a breakpoint on 2915 xmlMallocBreakpoint() a specific function called when this precise block 2916 is allocated</li> 2917 <li>when the breakpoint is reached you can then do a fine analysis of the 2918 allocation an step to see the condition resulting in the missing 2919 deallocation.</li> 2920</ol> 2921 2922<p>I used to use a commercial tool to debug libxml2 memory problems but after 2923noticing that it was not detecting memory leaks that simple mechanism was 2924used and proved extremely efficient until now. Lately I have also used <a 2925href="http://developer.kde.org/~sewardj/">valgrind</a> with quite some 2926success, it is tied to the i386 architecture since it works by emulating the 2927processor and instruction set, it is slow but extremely efficient, i.e. it 2928spot memory usage errors in a very precise way.</p> 2929 2930<h3><a name="General4">General memory requirements</a></h3> 2931 2932<p>How much libxml2 memory require ? It's hard to tell in average it depends 2933of a number of things:</p> 2934<ul> 2935 <li>the parser itself should work in a fixed amount of memory, except for 2936 information maintained about the stacks of names and entities locations. 2937 The I/O and encoding handlers will probably account for a few KBytes. 2938 This is true for both the XML and HTML parser (though the HTML parser 2939 need more state).</li> 2940 <li>If you are generating the DOM tree then memory requirements will grow 2941 nearly linear with the size of the data. In general for a balanced 2942 textual document the internal memory requirement is about 4 times the 2943 size of the UTF8 serialization of this document (example the XML-1.0 2944 recommendation is a bit more of 150KBytes and takes 650KBytes of main 2945 memory when parsed). Validation will add a amount of memory required for 2946 maintaining the external Dtd state which should be linear with the 2947 complexity of the content model defined by the Dtd</li> 2948 <li>If you need to work with fixed memory requirements or don't need the 2949 full DOM tree then using the <a href="xmlreader.html">xmlReader 2950 interface</a> is probably the best way to proceed, it still allows to 2951 validate or operate on subset of the tree if needed.</li> 2952 <li>If you don't care about the advanced features of libxml2 like 2953 validation, DOM, XPath or XPointer, don't use entities, need to work with 2954 fixed memory requirements, and try to get the fastest parsing possible 2955 then the SAX interface should be used, but it has known restrictions.</li> 2956</ul> 2957 2958<p></p> 2959 2960<h2><a name="Encodings">Encodings support</a></h2> 2961 2962<p>Table of Content:</p> 2963<ol> 2964 <li><a href="encoding.html#What">What does internationalization support 2965 mean ?</a></li> 2966 <li><a href="encoding.html#internal">The internal encoding, how and 2967 why</a></li> 2968 <li><a href="encoding.html#implemente">How is it implemented ?</a></li> 2969 <li><a href="encoding.html#Default">Default supported encodings</a></li> 2970 <li><a href="encoding.html#extend">How to extend the existing 2971 support</a></li> 2972</ol> 2973 2974<h3><a name="What">What does internationalization support mean ?</a></h3> 2975 2976<p>If you are not really familiar with Internationalization (usual shortcut 2977is I18N) , Unicode, characters and glyphs, I suggest you read a <a 2978href="http://www.tbray.org/ongoing/When/200x/2003/04/06/Unicode">presentation</a> 2979by Tim Bray on Unicode and why you should care about it.</p> 2980 2981<p>XML was designed from the start to allow the support of any character set 2982by using Unicode. Any conformant XML parser has to support the UTF-8 and 2983UTF-16 default encodings which can both express the full unicode ranges. UTF8 2984is a variable length encoding whose greatest points are to reuse the same 2985encoding for ASCII and to save space for Western encodings, but it is a bit 2986more complex to handle in practice. UTF-16 use 2 bytes per character (and 2987sometimes combines two pairs), it makes implementation easier, but looks a 2988bit overkill for Western languages encoding. Moreover the XML specification 2989allows the document to be encoded in other encodings at the condition that 2990they are clearly labeled as such. For example the following is a wellformed 2991XML document encoded in ISO-8859-1 and using accentuated letters that we 2992French like for both markup and content:</p> 2993<pre><?xml version="1.0" encoding="ISO-8859-1"?> 2994<tr�s>l�</tr�s></pre> 2995 2996<p>Having internationalization support in libxml2 means the following:</p> 2997<ul> 2998 <li>the document is properly parsed</li> 2999 <li>informations about it's encoding are saved</li> 3000 <li>it can be modified</li> 3001 <li>it can be saved in its original encoding</li> 3002 <li>it can also be saved in another encoding supported by libxml2 (for 3003 example straight UTF8 or even an ASCII form)</li> 3004</ul> 3005 3006<p>Another very important point is that the whole libxml2 API, with the 3007exception of a few routines to read with a specific encoding or save to a 3008specific encoding, is completely agnostic about the original encoding of the 3009document.</p> 3010 3011<p>It should be noted too that the HTML parser embedded in libxml2 now obey 3012the same rules too, the following document will be (as of 2.2.2) handled in 3013an internationalized fashion by libxml2 too:</p> 3014<pre><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" 3015 "http://www.w3.org/TR/REC-html40/loose.dtd"> 3016<html lang="fr"> 3017<head> 3018 <META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=ISO-8859-1"> 3019</head> 3020<body> 3021<p>W3C cr�e des standards pour le Web.</body> 3022</html></pre> 3023 3024<h3><a name="internal">The internal encoding, how and why</a></h3> 3025 3026<p>One of the core decisions was to force all documents to be converted to a 3027default internal encoding, and that encoding to be UTF-8, here are the 3028rationales for those choices:</p> 3029<ul> 3030 <li>keeping the native encoding in the internal form would force the libxml 3031 users (or the code associated) to be fully aware of the encoding of the 3032 original document, for examples when adding a text node to a document, 3033 the content would have to be provided in the document encoding, i.e. the 3034 client code would have to check it before hand, make sure it's conformant 3035 to the encoding, etc ... Very hard in practice, though in some specific 3036 cases this may make sense.</li> 3037 <li>the second decision was which encoding. From the XML spec only UTF8 and 3038 UTF16 really makes sense as being the two only encodings for which there 3039 is mandatory support. UCS-4 (32 bits fixed size encoding) could be 3040 considered an intelligent choice too since it's a direct Unicode mapping 3041 support. I selected UTF-8 on the basis of efficiency and compatibility 3042 with surrounding software: 3043 <ul> 3044 <li>UTF-8 while a bit more complex to convert from/to (i.e. slightly 3045 more costly to import and export CPU wise) is also far more compact 3046 than UTF-16 (and UCS-4) for a majority of the documents I see it used 3047 for right now (RPM RDF catalogs, advogato data, various configuration 3048 file formats, etc.) and the key point for today's computer 3049 architecture is efficient uses of caches. If one nearly double the 3050 memory requirement to store the same amount of data, this will trash 3051 caches (main memory/external caches/internal caches) and my take is 3052 that this harms the system far more than the CPU requirements needed 3053 for the conversion to UTF-8</li> 3054 <li>Most of libxml2 version 1 users were using it with straight ASCII 3055 most of the time, doing the conversion with an internal encoding 3056 requiring all their code to be rewritten was a serious show-stopper 3057 for using UTF-16 or UCS-4.</li> 3058 <li>UTF-8 is being used as the de-facto internal encoding standard for 3059 related code like the <a href="http://www.pango.org/">pango</a> 3060 upcoming Gnome text widget, and a lot of Unix code (yet another place 3061 where Unix programmer base takes a different approach from Microsoft 3062 - they are using UTF-16)</li> 3063 </ul> 3064 </li> 3065</ul> 3066 3067<p>What does this mean in practice for the libxml2 user:</p> 3068<ul> 3069 <li>xmlChar, the libxml2 data type is a byte, those bytes must be assembled 3070 as UTF-8 valid strings. The proper way to terminate an xmlChar * string 3071 is simply to append 0 byte, as usual.</li> 3072 <li>One just need to make sure that when using chars outside the ASCII set, 3073 the values has been properly converted to UTF-8</li> 3074</ul> 3075 3076<h3><a name="implemente">How is it implemented ?</a></h3> 3077 3078<p>Let's describe how all this works within libxml, basically the I18N 3079(internationalization) support get triggered only during I/O operation, i.e. 3080when reading a document or saving one. Let's look first at the reading 3081sequence:</p> 3082<ol> 3083 <li>when a document is processed, we usually don't know the encoding, a 3084 simple heuristic allows to detect UTF-16 and UCS-4 from encodings where 3085 the ASCII range (0-0x7F) maps with ASCII</li> 3086 <li>the xml declaration if available is parsed, including the encoding 3087 declaration. At that point, if the autodetected encoding is different 3088 from the one declared a call to xmlSwitchEncoding() is issued.</li> 3089 <li>If there is no encoding declaration, then the input has to be in either 3090 UTF-8 or UTF-16, if it is not then at some point when processing the 3091 input, the converter/checker of UTF-8 form will raise an encoding error. 3092 You may end-up with a garbled document, or no document at all ! Example: 3093 <pre>~/XML -> /xmllint err.xml 3094err.xml:1: error: Input is not proper UTF-8, indicate encoding ! 3095<tr�s>l�</tr�s> 3096 ^ 3097err.xml:1: error: Bytes: 0xE8 0x73 0x3E 0x6C 3098<tr�s>l�</tr�s> 3099 ^</pre> 3100 </li> 3101 <li>xmlSwitchEncoding() does an encoding name lookup, canonicalize it, and 3102 then search the default registered encoding converters for that encoding. 3103 If it's not within the default set and iconv() support has been compiled 3104 it, it will ask iconv for such an encoder. If this fails then the parser 3105 will report an error and stops processing: 3106 <pre>~/XML -> /xmllint err2.xml 3107err2.xml:1: error: Unsupported encoding UnsupportedEnc 3108<?xml version="1.0" encoding="UnsupportedEnc"?> 3109 ^</pre> 3110 </li> 3111 <li>From that point the encoder processes progressively the input (it is 3112 plugged as a front-end to the I/O module) for that entity. It captures 3113 and converts on-the-fly the document to be parsed to UTF-8. The parser 3114 itself just does UTF-8 checking of this input and process it 3115 transparently. The only difference is that the encoding information has 3116 been added to the parsing context (more precisely to the input 3117 corresponding to this entity).</li> 3118 <li>The result (when using DOM) is an internal form completely in UTF-8 3119 with just an encoding information on the document node.</li> 3120</ol> 3121 3122<p>Ok then what happens when saving the document (assuming you 3123collected/built an xmlDoc DOM like structure) ? It depends on the function 3124called, xmlSaveFile() will just try to save in the original encoding, while 3125xmlSaveFileTo() and xmlSaveFileEnc() can optionally save to a given 3126encoding:</p> 3127<ol> 3128 <li>if no encoding is given, libxml2 will look for an encoding value 3129 associated to the document and if it exists will try to save to that 3130 encoding, 3131 <p>otherwise everything is written in the internal form, i.e. UTF-8</p> 3132 </li> 3133 <li>so if an encoding was specified, either at the API level or on the 3134 document, libxml2 will again canonicalize the encoding name, lookup for a 3135 converter in the registered set or through iconv. If not found the 3136 function will return an error code</li> 3137 <li>the converter is placed before the I/O buffer layer, as another kind of 3138 buffer, then libxml2 will simply push the UTF-8 serialization to through 3139 that buffer, which will then progressively be converted and pushed onto 3140 the I/O layer.</li> 3141 <li>It is possible that the converter code fails on some input, for example 3142 trying to push an UTF-8 encoded Chinese character through the UTF-8 to 3143 ISO-8859-1 converter won't work. Since the encoders are progressive they 3144 will just report the error and the number of bytes converted, at that 3145 point libxml2 will decode the offending character, remove it from the 3146 buffer and replace it with the associated charRef encoding &#123; and 3147 resume the conversion. This guarantees that any document will be saved 3148 without losses (except for markup names where this is not legal, this is 3149 a problem in the current version, in practice avoid using non-ascii 3150 characters for tag or attribute names). A special "ascii" encoding name 3151 is used to save documents to a pure ascii form can be used when 3152 portability is really crucial</li> 3153</ol> 3154 3155<p>Here are a few examples based on the same test document:</p> 3156<pre>~/XML -> /xmllint isolat1 3157<?xml version="1.0" encoding="ISO-8859-1"?> 3158<tr�s>l�</tr�s> 3159~/XML -> /xmllint --encode UTF-8 isolat1 3160<?xml version="1.0" encoding="UTF-8"?> 3161<très>l� �</très> 3162~/XML -> </pre> 3163 3164<p>The same processing is applied (and reuse most of the code) for HTML I18N 3165processing. Looking up and modifying the content encoding is a bit more 3166difficult since it is located in a <meta> tag under the <head>, 3167so a couple of functions htmlGetMetaEncoding() and htmlSetMetaEncoding() have 3168been provided. The parser also attempts to switch encoding on the fly when 3169detecting such a tag on input. Except for that the processing is the same 3170(and again reuses the same code).</p> 3171 3172<h3><a name="Default">Default supported encodings</a></h3> 3173 3174<p>libxml2 has a set of default converters for the following encodings 3175(located in encoding.c):</p> 3176<ol> 3177 <li>UTF-8 is supported by default (null handlers)</li> 3178 <li>UTF-16, both little and big endian</li> 3179 <li>ISO-Latin-1 (ISO-8859-1) covering most western languages</li> 3180 <li>ASCII, useful mostly for saving</li> 3181 <li>HTML, a specific handler for the conversion of UTF-8 to ASCII with HTML 3182 predefined entities like &copy; for the Copyright sign.</li> 3183</ol> 3184 3185<p>More over when compiled on an Unix platform with iconv support the full 3186set of encodings supported by iconv can be instantly be used by libxml. On a 3187linux machine with glibc-2.1 the list of supported encodings and aliases fill 31883 full pages, and include UCS-4, the full set of ISO-Latin encodings, and the 3189various Japanese ones.</p> 3190 3191<h4>Encoding aliases</h4> 3192 3193<p>From 2.2.3, libxml2 has support to register encoding names aliases. The 3194goal is to be able to parse document whose encoding is supported but where 3195the name differs (for example from the default set of names accepted by 3196iconv). The following functions allow to register and handle new aliases for 3197existing encodings. Once registered libxml2 will automatically lookup the 3198aliases when handling a document:</p> 3199<ul> 3200 <li>int xmlAddEncodingAlias(const char *name, const char *alias);</li> 3201 <li>int xmlDelEncodingAlias(const char *alias);</li> 3202 <li>const char * xmlGetEncodingAlias(const char *alias);</li> 3203 <li>void xmlCleanupEncodingAliases(void);</li> 3204</ul> 3205 3206<h3><a name="extend">How to extend the existing support</a></h3> 3207 3208<p>Well adding support for new encoding, or overriding one of the encoders 3209(assuming it is buggy) should not be hard, just write input and output 3210conversion routines to/from UTF-8, and register them using 3211xmlNewCharEncodingHandler(name, xxxToUTF8, UTF8Toxxx), and they will be 3212called automatically if the parser(s) encounter such an encoding name 3213(register it uppercase, this will help). The description of the encoders, 3214their arguments and expected return values are described in the encoding.h 3215header.</p> 3216 3217<p>A quick note on the topic of subverting the parser to use a different 3218internal encoding than UTF-8, in some case people will absolutely want to 3219keep the internal encoding different, I think it's still possible (but the 3220encoding must be compliant with ASCII on the same subrange) though I didn't 3221tried it. The key is to override the default conversion routines (by 3222registering null encoders/decoders for your charsets), and bypass the UTF-8 3223checking of the parser by setting the parser context charset 3224(ctxt->charset) to something different than XML_CHAR_ENCODING_UTF8, but 3225there is no guarantee that this will work. You may also have some troubles 3226saving back.</p> 3227 3228<p>Basically proper I18N support is important, this requires at least 3229libxml-2.0.0, but a lot of features and corrections are really available only 3230starting 2.2.</p> 3231 3232<h2><a name="IO">I/O Interfaces</a></h2> 3233 3234<p>Table of Content:</p> 3235<ol> 3236 <li><a href="#General1">General overview</a></li> 3237 <li><a href="#basic">The basic buffer type</a></li> 3238 <li><a href="#Input">Input I/O handlers</a></li> 3239 <li><a href="#Output">Output I/O handlers</a></li> 3240 <li><a href="#entities">The entities loader</a></li> 3241 <li><a href="#Example2">Example of customized I/O</a></li> 3242</ol> 3243 3244<h3><a name="General1">General overview</a></h3> 3245 3246<p>The module <code><a 3247href="http://xmlsoft.org/html/libxml-xmlio.html">xmlIO.h</a></code> provides 3248the interfaces to the libxml2 I/O system. This consists of 4 main parts:</p> 3249<ul> 3250 <li>Entities loader, this is a routine which tries to fetch the entities 3251 (files) based on their PUBLIC and SYSTEM identifiers. The default loader 3252 don't look at the public identifier since libxml2 do not maintain a 3253 catalog. You can redefine you own entity loader by using 3254 <code>xmlGetExternalEntityLoader()</code> and 3255 <code>xmlSetExternalEntityLoader()</code>. <a href="#entities">Check the 3256 example</a>.</li> 3257 <li>Input I/O buffers which are a commodity structure used by the parser(s) 3258 input layer to handle fetching the informations to feed the parser. This 3259 provides buffering and is also a placeholder where the encoding 3260 converters to UTF8 are piggy-backed.</li> 3261 <li>Output I/O buffers are similar to the Input ones and fulfill similar 3262 task but when generating a serialization from a tree.</li> 3263 <li>A mechanism to register sets of I/O callbacks and associate them with 3264 specific naming schemes like the protocol part of the URIs. 3265 <p>This affect the default I/O operations and allows to use specific I/O 3266 handlers for certain names.</p> 3267 </li> 3268</ul> 3269 3270<p>The general mechanism used when loading http://rpmfind.net/xml.html for 3271example in the HTML parser is the following:</p> 3272<ol> 3273 <li>The default entity loader calls <code>xmlNewInputFromFile()</code> with 3274 the parsing context and the URI string.</li> 3275 <li>the URI string is checked against the existing registered handlers 3276 using their match() callback function, if the HTTP module was compiled 3277 in, it is registered and its match() function will succeeds</li> 3278 <li>the open() function of the handler is called and if successful will 3279 return an I/O Input buffer</li> 3280 <li>the parser will the start reading from this buffer and progressively 3281 fetch information from the resource, calling the read() function of the 3282 handler until the resource is exhausted</li> 3283 <li>if an encoding change is detected it will be installed on the input 3284 buffer, providing buffering and efficient use of the conversion 3285 routines</li> 3286 <li>once the parser has finished, the close() function of the handler is 3287 called once and the Input buffer and associated resources are 3288 deallocated.</li> 3289</ol> 3290 3291<p>The user defined callbacks are checked first to allow overriding of the 3292default libxml2 I/O routines.</p> 3293 3294<h3><a name="basic">The basic buffer type</a></h3> 3295 3296<p>All the buffer manipulation handling is done using the 3297<code>xmlBuffer</code> type define in <code><a 3298href="http://xmlsoft.org/html/libxml-tree.html">tree.h</a> </code>which is a 3299resizable memory buffer. The buffer allocation strategy can be selected to be 3300either best-fit or use an exponential doubling one (CPU vs. memory use 3301trade-off). The values are <code>XML_BUFFER_ALLOC_EXACT</code> and 3302<code>XML_BUFFER_ALLOC_DOUBLEIT</code>, and can be set individually or on a 3303system wide basis using <code>xmlBufferSetAllocationScheme()</code>. A number 3304of functions allows to manipulate buffers with names starting with the 3305<code>xmlBuffer...</code> prefix.</p> 3306 3307<h3><a name="Input">Input I/O handlers</a></h3> 3308 3309<p>An Input I/O handler is a simple structure 3310<code>xmlParserInputBuffer</code> containing a context associated to the 3311resource (file descriptor, or pointer to a protocol handler), the read() and 3312close() callbacks to use and an xmlBuffer. And extra xmlBuffer and a charset 3313encoding handler are also present to support charset conversion when 3314needed.</p> 3315 3316<h3><a name="Output">Output I/O handlers</a></h3> 3317 3318<p>An Output handler <code>xmlOutputBuffer</code> is completely similar to an 3319Input one except the callbacks are write() and close().</p> 3320 3321<h3><a name="entities">The entities loader</a></h3> 3322 3323<p>The entity loader resolves requests for new entities and create inputs for 3324the parser. Creating an input from a filename or an URI string is done 3325through the xmlNewInputFromFile() routine. The default entity loader do not 3326handle the PUBLIC identifier associated with an entity (if any). So it just 3327calls xmlNewInputFromFile() with the SYSTEM identifier (which is mandatory in 3328XML).</p> 3329 3330<p>If you want to hook up a catalog mechanism then you simply need to 3331override the default entity loader, here is an example:</p> 3332<pre>#include <libxml/xmlIO.h> 3333 3334xmlExternalEntityLoader defaultLoader = NULL; 3335 3336xmlParserInputPtr 3337xmlMyExternalEntityLoader(const char *URL, const char *ID, 3338 xmlParserCtxtPtr ctxt) { 3339 xmlParserInputPtr ret; 3340 const char *fileID = NULL; 3341 /* lookup for the fileID depending on ID */ 3342 3343 ret = xmlNewInputFromFile(ctxt, fileID); 3344 if (ret != NULL) 3345 return(ret); 3346 if (defaultLoader != NULL) 3347 ret = defaultLoader(URL, ID, ctxt); 3348 return(ret); 3349} 3350 3351int main(..) { 3352 ... 3353 3354 /* 3355 * Install our own entity loader 3356 */ 3357 defaultLoader = xmlGetExternalEntityLoader(); 3358 xmlSetExternalEntityLoader(xmlMyExternalEntityLoader); 3359 3360 ... 3361}</pre> 3362 3363<h3><a name="Example2">Example of customized I/O</a></h3> 3364 3365<p>This example come from <a href="http://xmlsoft.org/messages/0708.html">a 3366real use case</a>, xmlDocDump() closes the FILE * passed by the application 3367and this was a problem. The <a 3368href="http://xmlsoft.org/messages/0711.html">solution</a> was to redefine a 3369new output handler with the closing call deactivated:</p> 3370<ol> 3371 <li>First define a new I/O output allocator where the output don't close 3372 the file: 3373 <pre>xmlOutputBufferPtr 3374xmlOutputBufferCreateOwn(FILE *file, xmlCharEncodingHandlerPtr encoder) { 3375����xmlOutputBufferPtr ret; 3376���� 3377����if (xmlOutputCallbackInitialized == 0) 3378��������xmlRegisterDefaultOutputCallbacks(); 3379 3380����if (file == NULL) return(NULL); 3381����ret = xmlAllocOutputBuffer(encoder); 3382����if (ret != NULL) { 3383��������ret->context = file; 3384��������ret->writecallback = xmlFileWrite; 3385��������ret->closecallback = NULL; /* No close callback */ 3386����} 3387����return(ret); 3388} </pre> 3389 </li> 3390 <li>And then use it to save the document: 3391 <pre>FILE *f; 3392xmlOutputBufferPtr output; 3393xmlDocPtr doc; 3394int res; 3395 3396f = ... 3397doc = .... 3398 3399output = xmlOutputBufferCreateOwn(f, NULL); 3400res = xmlSaveFileTo(output, doc, NULL); 3401 </pre> 3402 </li> 3403</ol> 3404 3405<h2><a name="Catalog">Catalog support</a></h2> 3406 3407<p>Table of Content:</p> 3408<ol> 3409 <li><a href="General2">General overview</a></li> 3410 <li><a href="#definition">The definition</a></li> 3411 <li><a href="#Simple">Using catalogs</a></li> 3412 <li><a href="#Some">Some examples</a></li> 3413 <li><a href="#reference">How to tune catalog usage</a></li> 3414 <li><a href="#validate">How to debug catalog processing</a></li> 3415 <li><a href="#Declaring">How to create and maintain catalogs</a></li> 3416 <li><a href="#implemento">The implementor corner quick review of the 3417 API</a></li> 3418 <li><a href="#Other">Other resources</a></li> 3419</ol> 3420 3421<h3><a name="General2">General overview</a></h3> 3422 3423<p>What is a catalog? Basically it's a lookup mechanism used when an entity 3424(a file or a remote resource) references another entity. The catalog lookup 3425is inserted between the moment the reference is recognized by the software 3426(XML parser, stylesheet processing, or even images referenced for inclusion 3427in a rendering) and the time where loading that resource is actually 3428started.</p> 3429 3430<p>It is basically used for 3 things:</p> 3431<ul> 3432 <li>mapping from "logical" names, the public identifiers and a more 3433 concrete name usable for download (and URI). For example it can associate 3434 the logical name 3435 <p>"-//OASIS//DTD DocBook XML V4.1.2//EN"</p> 3436 <p>of the DocBook 4.1.2 XML DTD with the actual URL where it can be 3437 downloaded</p> 3438 <p>http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd</p> 3439 </li> 3440 <li>remapping from a given URL to another one, like an HTTP indirection 3441 saying that 3442 <p>"http://www.oasis-open.org/committes/tr.xsl"</p> 3443 <p>should really be looked at</p> 3444 <p>"http://www.oasis-open.org/committes/entity/stylesheets/base/tr.xsl"</p> 3445 </li> 3446 <li>providing a local cache mechanism allowing to load the entities 3447 associated to public identifiers or remote resources, this is a really 3448 important feature for any significant deployment of XML or SGML since it 3449 allows to avoid the aleas and delays associated to fetching remote 3450 resources.</li> 3451</ul> 3452 3453<h3><a name="definition">The definitions</a></h3> 3454 3455<p>Libxml, as of 2.4.3 implements 2 kind of catalogs:</p> 3456<ul> 3457 <li>the older SGML catalogs, the official spec is SGML Open Technical 3458 Resolution TR9401:1997, but is better understood by reading <a 3459 href="http://www.jclark.com/sp/catalog.htm">the SP Catalog page</a> from 3460 James Clark. This is relatively old and not the preferred mode of 3461 operation of libxml.</li> 3462 <li><a href="http://www.oasis-open.org/committees/entity/spec.html">XML 3463 Catalogs</a> is far more flexible, more recent, uses an XML syntax and 3464 should scale quite better. This is the default option of libxml.</li> 3465</ul> 3466 3467<p></p> 3468 3469<h3><a name="Simple">Using catalog</a></h3> 3470 3471<p>In a normal environment libxml2 will by default check the presence of a 3472catalog in /etc/xml/catalog, and assuming it has been correctly populated, 3473the processing is completely transparent to the document user. To take a 3474concrete example, suppose you are authoring a DocBook document, this one 3475starts with the following DOCTYPE definition:</p> 3476<pre><?xml version='1.0'?> 3477<!DOCTYPE book PUBLIC "-//Norman Walsh//DTD DocBk XML V3.1.4//EN" 3478 "http://nwalsh.com/docbook/xml/3.1.4/db3xml.dtd"></pre> 3479 3480<p>When validating the document with libxml, the catalog will be 3481automatically consulted to lookup the public identifier "-//Norman Walsh//DTD 3482DocBk XML V3.1.4//EN" and the system identifier 3483"http://nwalsh.com/docbook/xml/3.1.4/db3xml.dtd", and if these entities have 3484been installed on your system and the catalogs actually point to them, libxml 3485will fetch them from the local disk.</p> 3486 3487<p style="font-size: 10pt"><strong>Note</strong>: Really don't use this 3488DOCTYPE example it's a really old version, but is fine as an example.</p> 3489 3490<p>Libxml2 will check the catalog each time that it is requested to load an 3491entity, this includes DTD, external parsed entities, stylesheets, etc ... If 3492your system is correctly configured all the authoring phase and processing 3493should use only local files, even if your document stays portable because it 3494uses the canonical public and system ID, referencing the remote document.</p> 3495 3496<h3><a name="Some">Some examples:</a></h3> 3497 3498<p>Here is a couple of fragments from XML Catalogs used in libxml2 early 3499regression tests in <code>test/catalogs</code> :</p> 3500<pre><?xml version="1.0"?> 3501<!DOCTYPE catalog PUBLIC 3502 "-//OASIS//DTD Entity Resolution XML Catalog V1.0//EN" 3503 "http://www.oasis-open.org/committees/entity/release/1.0/catalog.dtd"> 3504<catalog xmlns="urn:oasis:names:tc:entity:xmlns:xml:catalog"> 3505 <public publicId="-//OASIS//DTD DocBook XML V4.1.2//EN" 3506 uri="http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd"/> 3507...</pre> 3508 3509<p>This is the beginning of a catalog for DocBook 4.1.2, XML Catalogs are 3510written in XML, there is a specific namespace for catalog elements 3511"urn:oasis:names:tc:entity:xmlns:xml:catalog". The first entry in this 3512catalog is a <code>public</code> mapping it allows to associate a Public 3513Identifier with an URI.</p> 3514<pre>... 3515 <rewriteSystem systemIdStartString="http://www.oasis-open.org/docbook/" 3516 rewritePrefix="file:///usr/share/xml/docbook/"/> 3517...</pre> 3518 3519<p>A <code>rewriteSystem</code> is a very powerful instruction, it says that 3520any URI starting with a given prefix should be looked at another URI 3521constructed by replacing the prefix with an new one. In effect this acts like 3522a cache system for a full area of the Web. In practice it is extremely useful 3523with a file prefix if you have installed a copy of those resources on your 3524local system.</p> 3525<pre>... 3526<delegatePublic publicIdStartString="-//OASIS//DTD XML Catalog //" 3527 catalog="file:///usr/share/xml/docbook.xml"/> 3528<delegatePublic publicIdStartString="-//OASIS//ENTITIES DocBook XML" 3529 catalog="file:///usr/share/xml/docbook.xml"/> 3530<delegatePublic publicIdStartString="-//OASIS//DTD DocBook XML" 3531 catalog="file:///usr/share/xml/docbook.xml"/> 3532<delegateSystem systemIdStartString="http://www.oasis-open.org/docbook/" 3533 catalog="file:///usr/share/xml/docbook.xml"/> 3534<delegateURI uriStartString="http://www.oasis-open.org/docbook/" 3535 catalog="file:///usr/share/xml/docbook.xml"/> 3536...</pre> 3537 3538<p>Delegation is the core features which allows to build a tree of catalogs, 3539easier to maintain than a single catalog, based on Public Identifier, System 3540Identifier or URI prefixes it instructs the catalog software to look up 3541entries in another resource. This feature allow to build hierarchies of 3542catalogs, the set of entries presented should be sufficient to redirect the 3543resolution of all DocBook references to the specific catalog in 3544<code>/usr/share/xml/docbook.xml</code> this one in turn could delegate all 3545references for DocBook 4.2.1 to a specific catalog installed at the same time 3546as the DocBook resources on the local machine.</p> 3547 3548<h3><a name="reference">How to tune catalog usage:</a></h3> 3549 3550<p>The user can change the default catalog behaviour by redirecting queries 3551to its own set of catalogs, this can be done by setting the 3552<code>XML_CATALOG_FILES</code> environment variable to a list of catalogs, an 3553empty one should deactivate loading the default <code>/etc/xml/catalog</code> 3554default catalog</p> 3555 3556<h3><a name="validate">How to debug catalog processing:</a></h3> 3557 3558<p>Setting up the <code>XML_DEBUG_CATALOG</code> environment variable will 3559make libxml2 output debugging informations for each catalog operations, for 3560example:</p> 3561<pre>orchis:~/XML -> xmllint --memory --noout test/ent2 3562warning: failed to load external entity "title.xml" 3563orchis:~/XML -> export XML_DEBUG_CATALOG= 3564orchis:~/XML -> xmllint --memory --noout test/ent2 3565Failed to parse catalog /etc/xml/catalog 3566Failed to parse catalog /etc/xml/catalog 3567warning: failed to load external entity "title.xml" 3568Catalogs cleanup 3569orchis:~/XML -> </pre> 3570 3571<p>The test/ent2 references an entity, running the parser from memory makes 3572the base URI unavailable and the the "title.xml" entity cannot be loaded. 3573Setting up the debug environment variable allows to detect that an attempt is 3574made to load the <code>/etc/xml/catalog</code> but since it's not present the 3575resolution fails.</p> 3576 3577<p>But the most advanced way to debug XML catalog processing is to use the 3578<strong>xmlcatalog</strong> command shipped with libxml2, it allows to load 3579catalogs and make resolution queries to see what is going on. This is also 3580used for the regression tests:</p> 3581<pre>orchis:~/XML -> /xmlcatalog test/catalogs/docbook.xml \ 3582 "-//OASIS//DTD DocBook XML V4.1.2//EN" 3583http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd 3584orchis:~/XML -> </pre> 3585 3586<p>For debugging what is going on, adding one -v flags increase the verbosity 3587level to indicate the processing done (adding a second flag also indicate 3588what elements are recognized at parsing):</p> 3589<pre>orchis:~/XML -> /xmlcatalog -v test/catalogs/docbook.xml \ 3590 "-//OASIS//DTD DocBook XML V4.1.2//EN" 3591Parsing catalog test/catalogs/docbook.xml's content 3592Found public match -//OASIS//DTD DocBook XML V4.1.2//EN 3593http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd 3594Catalogs cleanup 3595orchis:~/XML -> </pre> 3596 3597<p>A shell interface is also available to debug and process multiple queries 3598(and for regression tests):</p> 3599<pre>orchis:~/XML -> /xmlcatalog -shell test/catalogs/docbook.xml \ 3600 "-//OASIS//DTD DocBook XML V4.1.2//EN" 3601> help 3602Commands available: 3603public PublicID: make a PUBLIC identifier lookup 3604system SystemID: make a SYSTEM identifier lookup 3605resolve PublicID SystemID: do a full resolver lookup 3606add 'type' 'orig' 'replace' : add an entry 3607del 'values' : remove values 3608dump: print the current catalog state 3609debug: increase the verbosity level 3610quiet: decrease the verbosity level 3611exit: quit the shell 3612> public "-//OASIS//DTD DocBook XML V4.1.2//EN" 3613http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd 3614> quit 3615orchis:~/XML -> </pre> 3616 3617<p>This should be sufficient for most debugging purpose, this was actually 3618used heavily to debug the XML Catalog implementation itself.</p> 3619 3620<h3><a name="Declaring">How to create and maintain</a> catalogs:</h3> 3621 3622<p>Basically XML Catalogs are XML files, you can either use XML tools to 3623manage them or use <strong>xmlcatalog</strong> for this. The basic step is 3624to create a catalog the -create option provide this facility:</p> 3625<pre>orchis:~/XML -> /xmlcatalog --create tst.xml 3626<?xml version="1.0"?> 3627<!DOCTYPE catalog PUBLIC "-//OASIS//DTD Entity Resolution XML Catalog V1.0//EN" 3628 "http://www.oasis-open.org/committees/entity/release/1.0/catalog.dtd"> 3629<catalog xmlns="urn:oasis:names:tc:entity:xmlns:xml:catalog"/> 3630orchis:~/XML -> </pre> 3631 3632<p>By default xmlcatalog does not overwrite the original catalog and save the 3633result on the standard output, this can be overridden using the -noout 3634option. The <code>-add</code> command allows to add entries in the 3635catalog:</p> 3636<pre>orchis:~/XML -> /xmlcatalog --noout --create --add "public" \ 3637 "-//OASIS//DTD DocBook XML V4.1.2//EN" \ 3638 http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd tst.xml 3639orchis:~/XML -> cat tst.xml 3640<?xml version="1.0"?> 3641<!DOCTYPE catalog PUBLIC "-//OASIS//DTD Entity Resolution XML Catalog V1.0//EN" \ 3642 "http://www.oasis-open.org/committees/entity/release/1.0/catalog.dtd"> 3643<catalog xmlns="urn:oasis:names:tc:entity:xmlns:xml:catalog"> 3644<public publicId="-//OASIS//DTD DocBook XML V4.1.2//EN" 3645 uri="http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd"/> 3646</catalog> 3647orchis:~/XML -> </pre> 3648 3649<p>The <code>-add</code> option will always take 3 parameters even if some of 3650the XML Catalog constructs (like nextCatalog) will have only a single 3651argument, just pass a third empty string, it will be ignored.</p> 3652 3653<p>Similarly the <code>-del</code> option remove matching entries from the 3654catalog:</p> 3655<pre>orchis:~/XML -> /xmlcatalog --del \ 3656 "http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd" tst.xml 3657<?xml version="1.0"?> 3658<!DOCTYPE catalog PUBLIC "-//OASIS//DTD Entity Resolution XML Catalog V1.0//EN" 3659 "http://www.oasis-open.org/committees/entity/release/1.0/catalog.dtd"> 3660<catalog xmlns="urn:oasis:names:tc:entity:xmlns:xml:catalog"/> 3661orchis:~/XML -> </pre> 3662 3663<p>The catalog is now empty. Note that the matching of <code>-del</code> is 3664exact and would have worked in a similar fashion with the Public ID 3665string.</p> 3666 3667<p>This is rudimentary but should be sufficient to manage a not too complex 3668catalog tree of resources.</p> 3669 3670<h3><a name="implemento">The implementor corner quick review of the 3671API:</a></h3> 3672 3673<p>First, and like for every other module of libxml, there is an 3674automatically generated <a href="html/libxml-catalog.html">API page for 3675catalog support</a>.</p> 3676 3677<p>The header for the catalog interfaces should be included as:</p> 3678<pre>#include <libxml/catalog.h></pre> 3679 3680<p>The API is voluntarily kept very simple. First it is not obvious that 3681applications really need access to it since it is the default behaviour of 3682libxml2 (Note: it is possible to completely override libxml2 default catalog 3683by using <a href="html/libxml-parser.html">xmlSetExternalEntityLoader</a> to 3684plug an application specific resolver).</p> 3685 3686<p>Basically libxml2 support 2 catalog lists:</p> 3687<ul> 3688 <li>the default one, global shared by all the application</li> 3689 <li>a per-document catalog, this one is built if the document uses the 3690 <code>oasis-xml-catalog</code> PIs to specify its own catalog list, it is 3691 associated to the parser context and destroyed when the parsing context 3692 is destroyed.</li> 3693</ul> 3694 3695<p>the document one will be used first if it exists.</p> 3696 3697<h4>Initialization routines:</h4> 3698 3699<p>xmlInitializeCatalog(), xmlLoadCatalog() and xmlLoadCatalogs() should be 3700used at startup to initialize the catalog, if the catalog should be 3701initialized with specific values xmlLoadCatalog() or xmlLoadCatalogs() 3702should be called before xmlInitializeCatalog() which would otherwise do a 3703default initialization first.</p> 3704 3705<p>The xmlCatalogAddLocal() call is used by the parser to grow the document 3706own catalog list if needed.</p> 3707 3708<h4>Preferences setup:</h4> 3709 3710<p>The XML Catalog spec requires the possibility to select default 3711preferences between public and system delegation, 3712xmlCatalogSetDefaultPrefer() allows this, xmlCatalogSetDefaults() and 3713xmlCatalogGetDefaults() allow to control if XML Catalogs resolution should 3714be forbidden, allowed for global catalog, for document catalog or both, the 3715default is to allow both.</p> 3716 3717<p>And of course xmlCatalogSetDebug() allows to generate debug messages 3718(through the xmlGenericError() mechanism).</p> 3719 3720<h4>Querying routines:</h4> 3721 3722<p>xmlCatalogResolve(), xmlCatalogResolveSystem(), xmlCatalogResolvePublic() 3723and xmlCatalogResolveURI() are relatively explicit if you read the XML 3724Catalog specification they correspond to section 7 algorithms, they should 3725also work if you have loaded an SGML catalog with a simplified semantic.</p> 3726 3727<p>xmlCatalogLocalResolve() and xmlCatalogLocalResolveURI() are the same but 3728operate on the document catalog list</p> 3729 3730<h4>Cleanup and Miscellaneous:</h4> 3731 3732<p>xmlCatalogCleanup() free-up the global catalog, xmlCatalogFreeLocal() is 3733the per-document equivalent.</p> 3734 3735<p>xmlCatalogAdd() and xmlCatalogRemove() are used to dynamically modify the 3736first catalog in the global list, and xmlCatalogDump() allows to dump a 3737catalog state, those routines are primarily designed for xmlcatalog, I'm not 3738sure that exposing more complex interfaces (like navigation ones) would be 3739really useful.</p> 3740 3741<p>The xmlParseCatalogFile() is a function used to load XML Catalog files, 3742it's similar as xmlParseFile() except it bypass all catalog lookups, it's 3743provided because this functionality may be useful for client tools.</p> 3744 3745<h4>threaded environments:</h4> 3746 3747<p>Since the catalog tree is built progressively, some care has been taken to 3748try to avoid troubles in multithreaded environments. The code is now thread 3749safe assuming that the libxml2 library has been compiled with threads 3750support.</p> 3751 3752<p></p> 3753 3754<h3><a name="Other">Other resources</a></h3> 3755 3756<p>The XML Catalog specification is relatively recent so there isn't much 3757literature to point at:</p> 3758<ul> 3759 <li>You can find a good rant from Norm Walsh about <a 3760 href="http://www.arbortext.com/Think_Tank/XML_Resources/Issue_Three/issue_three.html">the 3761 need for catalogs</a>, it provides a lot of context informations even if 3762 I don't agree with everything presented. Norm also wrote a more recent 3763 article <a 3764 href="http://wwws.sun.com/software/xml/developers/resolver/article/">XML 3765 entities and URI resolvers</a> describing them.</li> 3766 <li>An <a href="http://home.ccil.org/~cowan/XML/XCatalog.html">old XML 3767 catalog proposal</a> from John Cowan</li> 3768 <li>The <a href="http://www.rddl.org/">Resource Directory Description 3769 Language</a> (RDDL) another catalog system but more oriented toward 3770 providing metadata for XML namespaces.</li> 3771 <li>the page from the OASIS Technical <a 3772 href="http://www.oasis-open.org/committees/entity/">Committee on Entity 3773 Resolution</a> who maintains XML Catalog, you will find pointers to the 3774 specification update, some background and pointers to others tools 3775 providing XML Catalog support</li> 3776 <li>There is a <a href="buildDocBookCatalog">shell script</a> to generate 3777 XML Catalogs for DocBook 4.1.2 . If it can write to the /etc/xml/ 3778 directory, it will set-up /etc/xml/catalog and /etc/xml/docbook based on 3779 the resources found on the system. Otherwise it will just create 3780 ~/xmlcatalog and ~/dbkxmlcatalog and doing: 3781 <p><code>export XML_CATALOG_FILES=$HOME/xmlcatalog</code></p> 3782 <p>should allow to process DocBook documentations without requiring 3783 network accesses for the DTD or stylesheets</p> 3784 </li> 3785 <li>I have uploaded <a href="ftp://xmlsoft.org/test/dbk412catalog.tar.gz">a 3786 small tarball</a> containing XML Catalogs for DocBook 4.1.2 which seems 3787 to work fine for me too</li> 3788 <li>The <a href="http://www.xmlsoft.org/xmlcatalog_man.html">xmlcatalog 3789 manual page</a></li> 3790</ul> 3791 3792<p>If you have suggestions for corrections or additions, simply contact 3793me:</p> 3794 3795<h2><a name="library">The parser interfaces</a></h2> 3796 3797<p>This section is directly intended to help programmers getting bootstrapped 3798using the XML tollkit from the C language. It is not intended to be 3799extensive. I hope the automatically generated documents will provide the 3800completeness required, but as a separate set of documents. The interfaces of 3801the XML parser are by principle low level, Those interested in a higher level 3802API should <a href="#DOM">look at DOM</a>.</p> 3803 3804<p>The <a href="html/libxml-parser.html">parser interfaces for XML</a> are 3805separated from the <a href="html/libxml-htmlparser.html">HTML parser 3806interfaces</a>. Let's have a look at how the XML parser can be called:</p> 3807 3808<h3><a name="Invoking">Invoking the parser : the pull method</a></h3> 3809 3810<p>Usually, the first thing to do is to read an XML input. The parser accepts 3811documents either from in-memory strings or from files. The functions are 3812defined in "parser.h":</p> 3813<dl> 3814 <dt><code>xmlDocPtr xmlParseMemory(char *buffer, int size);</code></dt> 3815 <dd><p>Parse a null-terminated string containing the document.</p> 3816 </dd> 3817</dl> 3818<dl> 3819 <dt><code>xmlDocPtr xmlParseFile(const char *filename);</code></dt> 3820 <dd><p>Parse an XML document contained in a (possibly compressed) 3821 file.</p> 3822 </dd> 3823</dl> 3824 3825<p>The parser returns a pointer to the document structure (or NULL in case of 3826failure).</p> 3827 3828<h3 id="Invoking1">Invoking the parser: the push method</h3> 3829 3830<p>In order for the application to keep the control when the document is 3831being fetched (which is common for GUI based programs) libxml2 provides a 3832push interface, too, as of version 1.8.3. Here are the interface 3833functions:</p> 3834<pre>xmlParserCtxtPtr xmlCreatePushParserCtxt(xmlSAXHandlerPtr sax, 3835 void *user_data, 3836 const char *chunk, 3837 int size, 3838 const char *filename); 3839int xmlParseChunk (xmlParserCtxtPtr ctxt, 3840 const char *chunk, 3841 int size, 3842 int terminate);</pre> 3843 3844<p>and here is a simple example showing how to use the interface:</p> 3845<pre> FILE *f; 3846 3847 f = fopen(filename, "r"); 3848 if (f != NULL) { 3849 int res, size = 1024; 3850 char chars[1024]; 3851 xmlParserCtxtPtr ctxt; 3852 3853 res = fread(chars, 1, 4, f); 3854 if (res > 0) { 3855 ctxt = xmlCreatePushParserCtxt(NULL, NULL, 3856 chars, res, filename); 3857 while ((res = fread(chars, 1, size, f)) > 0) { 3858 xmlParseChunk(ctxt, chars, res, 0); 3859 } 3860 xmlParseChunk(ctxt, chars, 0, 1); 3861 doc = ctxt->myDoc; 3862 xmlFreeParserCtxt(ctxt); 3863 } 3864 }</pre> 3865 3866<p>The HTML parser embedded into libxml2 also has a push interface; the 3867functions are just prefixed by "html" rather than "xml".</p> 3868 3869<h3 id="Invoking2">Invoking the parser: the SAX interface</h3> 3870 3871<p>The tree-building interface makes the parser memory-hungry, first loading 3872the document in memory and then building the tree itself. Reading a document 3873without building the tree is possible using the SAX interfaces (see SAX.h and 3874<a href="http://www.daa.com.au/~james/gnome/xml-sax/xml-sax.html">James 3875Henstridge's documentation</a>). Note also that the push interface can be 3876limited to SAX: just use the two first arguments of 3877<code>xmlCreatePushParserCtxt()</code>.</p> 3878 3879<h3><a name="Building">Building a tree from scratch</a></h3> 3880 3881<p>The other way to get an XML tree in memory is by building it. Basically 3882there is a set of functions dedicated to building new elements. (These are 3883also described in <libxml/tree.h>.) For example, here is a piece of 3884code that produces the XML document used in the previous examples:</p> 3885<pre> #include <libxml/tree.h> 3886 xmlDocPtr doc; 3887 xmlNodePtr tree, subtree; 3888 3889 doc = xmlNewDoc("1.0"); 3890 doc->children = xmlNewDocNode(doc, NULL, "EXAMPLE", NULL); 3891 xmlSetProp(doc->children, "prop1", "gnome is great"); 3892 xmlSetProp(doc->children, "prop2", "& linux too"); 3893 tree = xmlNewChild(doc->children, NULL, "head", NULL); 3894 subtree = xmlNewChild(tree, NULL, "title", "Welcome to Gnome"); 3895 tree = xmlNewChild(doc->children, NULL, "chapter", NULL); 3896 subtree = xmlNewChild(tree, NULL, "title", "The Linux adventure"); 3897 subtree = xmlNewChild(tree, NULL, "p", "bla bla bla ..."); 3898 subtree = xmlNewChild(tree, NULL, "image", NULL); 3899 xmlSetProp(subtree, "href", "linus.gif");</pre> 3900 3901<p>Not really rocket science ...</p> 3902 3903<h3><a name="Traversing">Traversing the tree</a></h3> 3904 3905<p>Basically by <a href="html/libxml-tree.html">including "tree.h"</a> your 3906code has access to the internal structure of all the elements of the tree. 3907The names should be somewhat simple like <strong>parent</strong>, 3908<strong>children</strong>, <strong>next</strong>, <strong>prev</strong>, 3909<strong>properties</strong>, etc... For example, still with the previous 3910example:</p> 3911<pre><code>doc->children->children->children</code></pre> 3912 3913<p>points to the title element,</p> 3914<pre>doc->children->children->next->children->children</pre> 3915 3916<p>points to the text node containing the chapter title "The Linux 3917adventure".</p> 3918 3919<p><strong>NOTE</strong>: XML allows <em>PI</em>s and <em>comments</em> to be 3920present before the document root, so <code>doc->children</code> may point 3921to an element which is not the document Root Element; a function 3922<code>xmlDocGetRootElement()</code> was added for this purpose.</p> 3923 3924<h3><a name="Modifying">Modifying the tree</a></h3> 3925 3926<p>Functions are provided for reading and writing the document content. Here 3927is an excerpt from the <a href="html/libxml-tree.html">tree API</a>:</p> 3928<dl> 3929 <dt><code>xmlAttrPtr xmlSetProp(xmlNodePtr node, const xmlChar *name, const 3930 xmlChar *value);</code></dt> 3931 <dd><p>This sets (or changes) an attribute carried by an ELEMENT node. 3932 The value can be NULL.</p> 3933 </dd> 3934</dl> 3935<dl> 3936 <dt><code>const xmlChar *xmlGetProp(xmlNodePtr node, const xmlChar 3937 *name);</code></dt> 3938 <dd><p>This function returns a pointer to new copy of the property 3939 content. Note that the user must deallocate the result.</p> 3940 </dd> 3941</dl> 3942 3943<p>Two functions are provided for reading and writing the text associated 3944with elements:</p> 3945<dl> 3946 <dt><code>xmlNodePtr xmlStringGetNodeList(xmlDocPtr doc, const xmlChar 3947 *value);</code></dt> 3948 <dd><p>This function takes an "external" string and converts it to one 3949 text node or possibly to a list of entity and text nodes. All 3950 non-predefined entity references like &Gnome; will be stored 3951 internally as entity nodes, hence the result of the function may not be 3952 a single node.</p> 3953 </dd> 3954</dl> 3955<dl> 3956 <dt><code>xmlChar *xmlNodeListGetString(xmlDocPtr doc, xmlNodePtr list, int 3957 inLine);</code></dt> 3958 <dd><p>This function is the inverse of 3959 <code>xmlStringGetNodeList()</code>. It generates a new string 3960 containing the content of the text and entity nodes. Note the extra 3961 argument inLine. If this argument is set to 1, the function will expand 3962 entity references. For example, instead of returning the &Gnome; 3963 XML encoding in the string, it will substitute it with its value (say, 3964 "GNU Network Object Model Environment").</p> 3965 </dd> 3966</dl> 3967 3968<h3><a name="Saving">Saving a tree</a></h3> 3969 3970<p>Basically 3 options are possible:</p> 3971<dl> 3972 <dt><code>void xmlDocDumpMemory(xmlDocPtr cur, xmlChar**mem, int 3973 *size);</code></dt> 3974 <dd><p>Returns a buffer into which the document has been saved.</p> 3975 </dd> 3976</dl> 3977<dl> 3978 <dt><code>extern void xmlDocDump(FILE *f, xmlDocPtr doc);</code></dt> 3979 <dd><p>Dumps a document to an open file descriptor.</p> 3980 </dd> 3981</dl> 3982<dl> 3983 <dt><code>int xmlSaveFile(const char *filename, xmlDocPtr cur);</code></dt> 3984 <dd><p>Saves the document to a file. In this case, the compression 3985 interface is triggered if it has been turned on.</p> 3986 </dd> 3987</dl> 3988 3989<h3><a name="Compressio">Compression</a></h3> 3990 3991<p>The library transparently handles compression when doing file-based 3992accesses. The level of compression on saves can be turned on either globally 3993or individually for one file:</p> 3994<dl> 3995 <dt><code>int xmlGetDocCompressMode (xmlDocPtr doc);</code></dt> 3996 <dd><p>Gets the document compression ratio (0-9).</p> 3997 </dd> 3998</dl> 3999<dl> 4000 <dt><code>void xmlSetDocCompressMode (xmlDocPtr doc, int mode);</code></dt> 4001 <dd><p>Sets the document compression ratio.</p> 4002 </dd> 4003</dl> 4004<dl> 4005 <dt><code>int xmlGetCompressMode(void);</code></dt> 4006 <dd><p>Gets the default compression ratio.</p> 4007 </dd> 4008</dl> 4009<dl> 4010 <dt><code>void xmlSetCompressMode(int mode);</code></dt> 4011 <dd><p>Sets the default compression ratio.</p> 4012 </dd> 4013</dl> 4014 4015<h2><a name="Entities">Entities or no entities</a></h2> 4016 4017<p>Entities in principle are similar to simple C macros. An entity defines an 4018abbreviation for a given string that you can reuse many times throughout the 4019content of your document. Entities are especially useful when a given string 4020may occur frequently within a document, or to confine the change needed to a 4021document to a restricted area in the internal subset of the document (at the 4022beginning). Example:</p> 4023<pre>1 <?xml version="1.0"?> 40242 <!DOCTYPE EXAMPLE SYSTEM "example.dtd" [ 40253 <!ENTITY xml "Extensible Markup Language"> 40264 ]> 40275 <EXAMPLE> 40286 &xml; 40297 </EXAMPLE></pre> 4030 4031<p>Line 3 declares the xml entity. Line 6 uses the xml entity, by prefixing 4032its name with '&' and following it by ';' without any spaces added. There 4033are 5 predefined entities in libxml2 allowing you to escape characters with 4034predefined meaning in some parts of the xml document content: 4035<strong>&lt;</strong> for the character '<', <strong>&gt;</strong> 4036for the character '>', <strong>&apos;</strong> for the character ''', 4037<strong>&quot;</strong> for the character '"', and 4038<strong>&amp;</strong> for the character '&'.</p> 4039 4040<p>One of the problems related to entities is that you may want the parser to 4041substitute an entity's content so that you can see the replacement text in 4042your application. Or you may prefer to keep entity references as such in the 4043content to be able to save the document back without losing this usually 4044precious information (if the user went through the pain of explicitly 4045defining entities, he may have a a rather negative attitude if you blindly 4046substitute them as saving time). The <a 4047href="html/libxml-parser.html#xmlSubstituteEntitiesDefault">xmlSubstituteEntitiesDefault()</a> 4048function allows you to check and change the behaviour, which is to not 4049substitute entities by default.</p> 4050 4051<p>Here is the DOM tree built by libxml2 for the previous document in the 4052default case:</p> 4053<pre>/gnome/src/gnome-xml -> /xmllint --debug test/ent1 4054DOCUMENT 4055version=1.0 4056 ELEMENT EXAMPLE 4057 TEXT 4058 content= 4059 ENTITY_REF 4060 INTERNAL_GENERAL_ENTITY xml 4061 content=Extensible Markup Language 4062 TEXT 4063 content=</pre> 4064 4065<p>And here is the result when substituting entities:</p> 4066<pre>/gnome/src/gnome-xml -> /tester --debug --noent test/ent1 4067DOCUMENT 4068version=1.0 4069 ELEMENT EXAMPLE 4070 TEXT 4071 content= Extensible Markup Language</pre> 4072 4073<p>So, entities or no entities? Basically, it depends on your use case. I 4074suggest that you keep the non-substituting default behaviour and avoid using 4075entities in your XML document or data if you are not willing to handle the 4076entity references elements in the DOM tree.</p> 4077 4078<p>Note that at save time libxml2 enforces the conversion of the predefined 4079entities where necessary to prevent well-formedness problems, and will also 4080transparently replace those with chars (i.e. it will not generate entity 4081reference elements in the DOM tree or call the reference() SAX callback when 4082finding them in the input).</p> 4083 4084<p><span style="background-color: #FF0000">WARNING</span>: handling entities 4085on top of the libxml2 SAX interface is difficult!!! If you plan to use 4086non-predefined entities in your documents, then the learning curve to handle 4087then using the SAX API may be long. If you plan to use complex documents, I 4088strongly suggest you consider using the DOM interface instead and let libxml 4089deal with the complexity rather than trying to do it yourself.</p> 4090 4091<h2><a name="Namespaces">Namespaces</a></h2> 4092 4093<p>The libxml2 library implements <a 4094href="http://www.w3.org/TR/REC-xml-names/">XML namespaces</a> support by 4095recognizing namespace constructs in the input, and does namespace lookup 4096automatically when building the DOM tree. A namespace declaration is 4097associated with an in-memory structure and all elements or attributes within 4098that namespace point to it. Hence testing the namespace is a simple and fast 4099equality operation at the user level.</p> 4100 4101<p>I suggest that people using libxml2 use a namespace, and declare it in the 4102root element of their document as the default namespace. Then they don't need 4103to use the prefix in the content but we will have a basis for future semantic 4104refinement and merging of data from different sources. This doesn't increase 4105the size of the XML output significantly, but significantly increases its 4106value in the long-term. Example:</p> 4107<pre><mydoc xmlns="http://mydoc.example.org/schemas/"> 4108 <elem1>...</elem1> 4109 <elem2>...</elem2> 4110</mydoc></pre> 4111 4112<p>The namespace value has to be an absolute URL, but the URL doesn't have to 4113point to any existing resource on the Web. It will bind all the element and 4114attributes with that URL. I suggest to use an URL within a domain you 4115control, and that the URL should contain some kind of version information if 4116possible. For example, <code>"http://www.gnome.org/gnumeric/1.0/"</code> is a 4117good namespace scheme.</p> 4118 4119<p>Then when you load a file, make sure that a namespace carrying the 4120version-independent prefix is installed on the root element of your document, 4121and if the version information don't match something you know, warn the user 4122and be liberal in what you accept as the input. Also do *not* try to base 4123namespace checking on the prefix value. <foo:text> may be exactly the 4124same as <bar:text> in another document. What really matters is the URI 4125associated with the element or the attribute, not the prefix string (which is 4126just a shortcut for the full URI). In libxml, element and attributes have an 4127<code>ns</code> field pointing to an xmlNs structure detailing the namespace 4128prefix and its URI.</p> 4129 4130<p>@@Interfaces@@</p> 4131<pre>xmlNodePtr node; 4132if(!strncmp(node->name,"mytag",5) 4133 && node->ns 4134 && !strcmp(node->ns->href,"http://www.mysite.com/myns/1.0")) { 4135 ... 4136}</pre> 4137 4138<p>Usually people object to using namespaces together with validity checking. 4139I will try to make sure that using namespaces won't break validity checking, 4140so even if you plan to use or currently are using validation I strongly 4141suggest adding namespaces to your document. A default namespace scheme 4142<code>xmlns="http://...."</code> should not break validity even on less 4143flexible parsers. Using namespaces to mix and differentiate content coming 4144from multiple DTDs will certainly break current validation schemes. To check 4145such documents one needs to use schema-validation, which is supported in 4146libxml2 as well. See <a href="http://www.relaxng.org/">relagx-ng</a> and <a 4147href="http://www.w3c.org/XML/Schema">w3c-schema</a>.</p> 4148 4149<h2><a name="Upgrading">Upgrading 1.x code</a></h2> 4150 4151<p>Incompatible changes:</p> 4152 4153<p>Version 2 of libxml2 is the first version introducing serious backward 4154incompatible changes. The main goals were:</p> 4155<ul> 4156 <li>a general cleanup. A number of mistakes inherited from the very early 4157 versions couldn't be changed due to compatibility constraints. Example 4158 the "childs" element in the nodes.</li> 4159 <li>Uniformization of the various nodes, at least for their header and link 4160 parts (doc, parent, children, prev, next), the goal is a simpler 4161 programming model and simplifying the task of the DOM implementors.</li> 4162 <li>better conformances to the XML specification, for example version 1.x 4163 had an heuristic to try to detect ignorable white spaces. As a result the 4164 SAX event generated were ignorableWhitespace() while the spec requires 4165 character() in that case. This also mean that a number of DOM node 4166 containing blank text may populate the DOM tree which were not present 4167 before.</li> 4168</ul> 4169 4170<h3>How to fix libxml-1.x code:</h3> 4171 4172<p>So client code of libxml designed to run with version 1.x may have to be 4173changed to compile against version 2.x of libxml. Here is a list of changes 4174that I have collected, they may not be sufficient, so in case you find other 4175change which are required, <a href="mailto:Daniel.Veillard@w3.org">drop me a 4176mail</a>:</p> 4177<ol> 4178 <li>The package name have changed from libxml to libxml2, the library name 4179 is now -lxml2 . There is a new xml2-config script which should be used to 4180 select the right parameters libxml2</li> 4181 <li>Node <strong>childs</strong> field has been renamed 4182 <strong>children</strong> so s/childs/children/g should be applied 4183 (probability of having "childs" anywhere else is close to 0+</li> 4184 <li>The document don't have anymore a <strong>root</strong> element it has 4185 been replaced by <strong>children</strong> and usually you will get a 4186 list of element here. For example a Dtd element for the internal subset 4187 and it's declaration may be found in that list, as well as processing 4188 instructions or comments found before or after the document root element. 4189 Use <strong>xmlDocGetRootElement(doc)</strong> to get the root element of 4190 a document. Alternatively if you are sure to not reference DTDs nor have 4191 PIs or comments before or after the root element 4192 s/->root/->children/g will probably do it.</li> 4193 <li>The white space issue, this one is more complex, unless special case of 4194 validating parsing, the line breaks and spaces usually used for indenting 4195 and formatting the document content becomes significant. So they are 4196 reported by SAX and if your using the DOM tree, corresponding nodes are 4197 generated. Too approach can be taken: 4198 <ol> 4199 <li>lazy one, use the compatibility call 4200 <strong>xmlKeepBlanksDefault(0)</strong> but be aware that you are 4201 relying on a special (and possibly broken) set of heuristics of 4202 libxml to detect ignorable blanks. Don't complain if it breaks or 4203 make your application not 100% clean w.r.t. to it's input.</li> 4204 <li>the Right Way: change you code to accept possibly insignificant 4205 blanks characters, or have your tree populated with weird blank text 4206 nodes. You can spot them using the commodity function 4207 <strong>xmlIsBlankNode(node)</strong> returning 1 for such blank 4208 nodes.</li> 4209 </ol> 4210 <p>Note also that with the new default the output functions don't add any 4211 extra indentation when saving a tree in order to be able to round trip 4212 (read and save) without inflating the document with extra formatting 4213 chars.</p> 4214 </li> 4215 <li>The include path has changed to $prefix/libxml/ and the includes 4216 themselves uses this new prefix in includes instructions... If you are 4217 using (as expected) the 4218 <pre>xml2-config --cflags</pre> 4219 <p>output to generate you compile commands this will probably work out of 4220 the box</p> 4221 </li> 4222 <li>xmlDetectCharEncoding takes an extra argument indicating the length in 4223 byte of the head of the document available for character detection.</li> 4224</ol> 4225 4226<h3>Ensuring both libxml-1.x and libxml-2.x compatibility</h3> 4227 4228<p>Two new version of libxml (1.8.11) and libxml2 (2.3.4) have been released 4229to allow smooth upgrade of existing libxml v1code while retaining 4230compatibility. They offers the following:</p> 4231<ol> 4232 <li>similar include naming, one should use 4233 <strong>#include<libxml/...></strong> in both cases.</li> 4234 <li>similar identifiers defined via macros for the child and root fields: 4235 respectively <strong>xmlChildrenNode</strong> and 4236 <strong>xmlRootNode</strong></li> 4237 <li>a new macro <strong>LIBXML_TEST_VERSION</strong> which should be 4238 inserted once in the client code</li> 4239</ol> 4240 4241<p>So the roadmap to upgrade your existing libxml applications is the 4242following:</p> 4243<ol> 4244 <li>install the libxml-1.8.8 (and libxml-devel-1.8.8) packages</li> 4245 <li>find all occurrences where the xmlDoc <strong>root</strong> field is 4246 used and change it to <strong>xmlRootNode</strong></li> 4247 <li>similarly find all occurrences where the xmlNode 4248 <strong>childs</strong> field is used and change it to 4249 <strong>xmlChildrenNode</strong></li> 4250 <li>add a <strong>LIBXML_TEST_VERSION</strong> macro somewhere in your 4251 <strong>main()</strong> or in the library init entry point</li> 4252 <li>Recompile, check compatibility, it should still work</li> 4253 <li>Change your configure script to look first for xml2-config and fall 4254 back using xml-config . Use the --cflags and --libs output of the command 4255 as the Include and Linking parameters needed to use libxml.</li> 4256 <li>install libxml2-2.3.x and libxml2-devel-2.3.x (libxml-1.8.y and 4257 libxml-devel-1.8.y can be kept simultaneously)</li> 4258 <li>remove your config.cache, relaunch your configuration mechanism, and 4259 recompile, if steps 2 and 3 were done right it should compile as-is</li> 4260 <li>Test that your application is still running correctly, if not this may 4261 be due to extra empty nodes due to formating spaces being kept in libxml2 4262 contrary to libxml1, in that case insert xmlKeepBlanksDefault(1) in your 4263 code before calling the parser (next to 4264 <strong>LIBXML_TEST_VERSION</strong> is a fine place).</li> 4265</ol> 4266 4267<p>Following those steps should work. It worked for some of my own code.</p> 4268 4269<p>Let me put some emphasis on the fact that there is far more changes from 4270libxml 1.x to 2.x than the ones you may have to patch for. The overall code 4271has been considerably cleaned up and the conformance to the XML specification 4272has been drastically improved too. Don't take those changes as an excuse to 4273not upgrade, it may cost a lot on the long term ...</p> 4274 4275<h2><a name="Thread">Thread safety</a></h2> 4276 4277<p>Starting with 2.4.7, libxml2 makes provisions to ensure that concurrent 4278threads can safely work in parallel parsing different documents. There is 4279however a couple of things to do to ensure it:</p> 4280<ul> 4281 <li>configure the library accordingly using the --with-threads options</li> 4282 <li>call xmlInitParser() in the "main" thread before using any of the 4283 libxml2 API (except possibly selecting a different memory allocator)</li> 4284</ul> 4285 4286<p>Note that the thread safety cannot be ensured for multiple threads sharing 4287the same document, the locking must be done at the application level, libxml 4288exports a basic mutex and reentrant mutexes API in <libxml/threads.h>. 4289The parts of the library checked for thread safety are:</p> 4290<ul> 4291 <li>concurrent loading</li> 4292 <li>file access resolution</li> 4293 <li>catalog access</li> 4294 <li>catalog building</li> 4295 <li>entities lookup/accesses</li> 4296 <li>validation</li> 4297 <li>global variables per-thread override</li> 4298 <li>memory handling</li> 4299</ul> 4300 4301<p>XPath is supposed to be thread safe now, but this wasn't tested 4302seriously.</p> 4303 4304<h2><a name="DOM"></a><a name="Principles">DOM Principles</a></h2> 4305 4306<p><a href="http://www.w3.org/DOM/">DOM</a> stands for the <em>Document 4307Object Model</em>; this is an API for accessing XML or HTML structured 4308documents. Native support for DOM in Gnome is on the way (module gnome-dom), 4309and will be based on gnome-xml. This will be a far cleaner interface to 4310manipulate XML files within Gnome since it won't expose the internal 4311structure.</p> 4312 4313<p>The current DOM implementation on top of libxml2 is the <a 4314href="http://cvs.gnome.org/lxr/source/gdome2/">gdome2 Gnome module</a>, this 4315is a full DOM interface, thanks to Paolo Casarini, check the <a 4316href="http://www.cs.unibo.it/~casarini/gdome2/">Gdome2 homepage</a> for more 4317informations.</p> 4318 4319<h2><a name="Example"></a><a name="real">A real example</a></h2> 4320 4321<p>Here is a real size example, where the actual content of the application 4322data is not kept in the DOM tree but uses internal structures. It is based on 4323a proposal to keep a database of jobs related to Gnome, with an XML based 4324storage structure. Here is an <a href="gjobs.xml">XML encoded jobs 4325base</a>:</p> 4326<pre><?xml version="1.0"?> 4327<gjob:Helping xmlns:gjob="http://www.gnome.org/some-location"> 4328 <gjob:Jobs> 4329 4330 <gjob:Job> 4331 <gjob:Project ID="3"/> 4332 <gjob:Application>GBackup</gjob:Application> 4333 <gjob:Category>Development</gjob:Category> 4334 4335 <gjob:Update> 4336 <gjob:Status>Open</gjob:Status> 4337 <gjob:Modified>Mon, 07 Jun 1999 20:27:45 -0400 MET DST</gjob:Modified> 4338 <gjob:Salary>USD 0.00</gjob:Salary> 4339 </gjob:Update> 4340 4341 <gjob:Developers> 4342 <gjob:Developer> 4343 </gjob:Developer> 4344 </gjob:Developers> 4345 4346 <gjob:Contact> 4347 <gjob:Person>Nathan Clemons</gjob:Person> 4348 <gjob:Email>nathan@windsofstorm.net</gjob:Email> 4349 <gjob:Company> 4350 </gjob:Company> 4351 <gjob:Organisation> 4352 </gjob:Organisation> 4353 <gjob:Webpage> 4354 </gjob:Webpage> 4355 <gjob:Snailmail> 4356 </gjob:Snailmail> 4357 <gjob:Phone> 4358 </gjob:Phone> 4359 </gjob:Contact> 4360 4361 <gjob:Requirements> 4362 The program should be released as free software, under the GPL. 4363 </gjob:Requirements> 4364 4365 <gjob:Skills> 4366 </gjob:Skills> 4367 4368 <gjob:Details> 4369 A GNOME based system that will allow a superuser to configure 4370 compressed and uncompressed files and/or file systems to be backed 4371 up with a supported media in the system. This should be able to 4372 perform via find commands generating a list of files that are passed 4373 to tar, dd, cpio, cp, gzip, etc., to be directed to the tape machine 4374 or via operations performed on the filesystem itself. Email 4375 notification and GUI status display very important. 4376 </gjob:Details> 4377 4378 </gjob:Job> 4379 4380 </gjob:Jobs> 4381</gjob:Helping></pre> 4382 4383<p>While loading the XML file into an internal DOM tree is a matter of 4384calling only a couple of functions, browsing the tree to gather the data and 4385generate the internal structures is harder, and more error prone.</p> 4386 4387<p>The suggested principle is to be tolerant with respect to the input 4388structure. For example, the ordering of the attributes is not significant, 4389the XML specification is clear about it. It's also usually a good idea not to 4390depend on the order of the children of a given node, unless it really makes 4391things harder. Here is some code to parse the information for a person:</p> 4392<pre>/* 4393 * A person record 4394 */ 4395typedef struct person { 4396 char *name; 4397 char *email; 4398 char *company; 4399 char *organisation; 4400 char *smail; 4401 char *webPage; 4402 char *phone; 4403} person, *personPtr; 4404 4405/* 4406 * And the code needed to parse it 4407 */ 4408personPtr parsePerson(xmlDocPtr doc, xmlNsPtr ns, xmlNodePtr cur) { 4409 personPtr ret = NULL; 4410 4411DEBUG("parsePerson\n"); 4412 /* 4413 * allocate the struct 4414 */ 4415 ret = (personPtr) malloc(sizeof(person)); 4416 if (ret == NULL) { 4417 fprintf(stderr,"out of memory\n"); 4418 return(NULL); 4419 } 4420 memset(ret, 0, sizeof(person)); 4421 4422 /* We don't care what the top level element name is */ 4423 cur = cur->xmlChildrenNode; 4424 while (cur != NULL) { 4425 if ((!strcmp(cur->name, "Person")) && (cur->ns == ns)) 4426 ret->name = xmlNodeListGetString(doc, cur->xmlChildrenNode, 1); 4427 if ((!strcmp(cur->name, "Email")) && (cur->ns == ns)) 4428 ret->email = xmlNodeListGetString(doc, cur->xmlChildrenNode, 1); 4429 cur = cur->next; 4430 } 4431 4432 return(ret); 4433}</pre> 4434 4435<p>Here are a couple of things to notice:</p> 4436<ul> 4437 <li>Usually a recursive parsing style is the more convenient one: XML data 4438 is by nature subject to repetitive constructs and usually exhibits highly 4439 structured patterns.</li> 4440 <li>The two arguments of type <em>xmlDocPtr</em> and <em>xmlNsPtr</em>, 4441 i.e. the pointer to the global XML document and the namespace reserved to 4442 the application. Document wide information are needed for example to 4443 decode entities and it's a good coding practice to define a namespace for 4444 your application set of data and test that the element and attributes 4445 you're analyzing actually pertains to your application space. This is 4446 done by a simple equality test (cur->ns == ns).</li> 4447 <li>To retrieve text and attributes value, you can use the function 4448 <em>xmlNodeListGetString</em> to gather all the text and entity reference 4449 nodes generated by the DOM output and produce an single text string.</li> 4450</ul> 4451 4452<p>Here is another piece of code used to parse another level of the 4453structure:</p> 4454<pre>#include <libxml/tree.h> 4455/* 4456 * a Description for a Job 4457 */ 4458typedef struct job { 4459 char *projectID; 4460 char *application; 4461 char *category; 4462 personPtr contact; 4463 int nbDevelopers; 4464 personPtr developers[100]; /* using dynamic alloc is left as an exercise */ 4465} job, *jobPtr; 4466 4467/* 4468 * And the code needed to parse it 4469 */ 4470jobPtr parseJob(xmlDocPtr doc, xmlNsPtr ns, xmlNodePtr cur) { 4471 jobPtr ret = NULL; 4472 4473DEBUG("parseJob\n"); 4474 /* 4475 * allocate the struct 4476 */ 4477 ret = (jobPtr) malloc(sizeof(job)); 4478 if (ret == NULL) { 4479 fprintf(stderr,"out of memory\n"); 4480 return(NULL); 4481 } 4482 memset(ret, 0, sizeof(job)); 4483 4484 /* We don't care what the top level element name is */ 4485 cur = cur->xmlChildrenNode; 4486 while (cur != NULL) { 4487 4488 if ((!strcmp(cur->name, "Project")) && (cur->ns == ns)) { 4489 ret->projectID = xmlGetProp(cur, "ID"); 4490 if (ret->projectID == NULL) { 4491 fprintf(stderr, "Project has no ID\n"); 4492 } 4493 } 4494 if ((!strcmp(cur->name, "Application")) && (cur->ns == ns)) 4495 ret->application = xmlNodeListGetString(doc, cur->xmlChildrenNode, 1); 4496 if ((!strcmp(cur->name, "Category")) && (cur->ns == ns)) 4497 ret->category = xmlNodeListGetString(doc, cur->xmlChildrenNode, 1); 4498 if ((!strcmp(cur->name, "Contact")) && (cur->ns == ns)) 4499 ret->contact = parsePerson(doc, ns, cur); 4500 cur = cur->next; 4501 } 4502 4503 return(ret); 4504}</pre> 4505 4506<p>Once you are used to it, writing this kind of code is quite simple, but 4507boring. Ultimately, it could be possible to write stubbers taking either C 4508data structure definitions, a set of XML examples or an XML DTD and produce 4509the code needed to import and export the content between C data and XML 4510storage. This is left as an exercise to the reader :-)</p> 4511 4512<p>Feel free to use <a href="example/gjobread.c">the code for the full C 4513parsing example</a> as a template, it is also available with Makefile in the 4514Gnome CVS base under gnome-xml/example</p> 4515 4516<h2><a name="Contributi">Contributions</a></h2> 4517<ul> 4518 <li>Bjorn Reese, William Brack and Thomas Broyer have provided a number of 4519 patches, Gary Pennington worked on the validation API, threading support 4520 and Solaris port.</li> 4521 <li>John Fleck helps maintaining the documentation and man pages.</li> 4522 <li><a href="mailto:igor@zlatkovic.com">Igor Zlatkovic</a> is now the 4523 maintainer of the Windows port, <a 4524 href="http://www.zlatkovic.com/projects/libxml/index.html">he provides 4525 binaries</a></li> 4526 <li><a href="mailto:Gary.Pennington@sun.com">Gary Pennington</a> provides 4527 <a href="http://garypennington.net/libxml2/">Solaris binaries</a></li> 4528 <li><a 4529 href="http://mail.gnome.org/archives/xml/2001-March/msg00014.html">Matt 4530 Sergeant</a> developed <a 4531 href="http://axkit.org/download/">XML::LibXSLT</a>, a Perl wrapper for 4532 libxml2/libxslt as part of the <a href="http://axkit.com/">AxKit XML 4533 application server</a></li> 4534 <li><a href="mailto:fnatter@gmx.net">Felix Natter</a> and <a 4535 href="mailto:geertk@ai.rug.nl">Geert Kloosterman</a> provide <a 4536 href="libxml-doc.el">an emacs module</a> to lookup libxml(2) functions 4537 documentation</li> 4538 <li><a href="mailto:sherwin@nlm.nih.gov">Ziying Sherwin</a> provided <a 4539 href="http://xmlsoft.org/messages/0488.html">man pages</a></li> 4540 <li>there is a module for <a 4541 href="http://acs-misc.sourceforge.net/nsxml.html">libxml/libxslt support 4542 in OpenNSD/AOLServer</a></li> 4543 <li><a href="mailto:dkuhlman@cutter.rexx.com">Dave Kuhlman</a> provided the 4544 first version of libxml/libxslt <a 4545 href="http://www.rexx.com/~dkuhlman">wrappers for Python</a></li> 4546 <li>Petr Kozelka provides <a 4547 href="http://sourceforge.net/projects/libxml2-pas">Pascal units to glue 4548 libxml2</a> with Kylix and Delphi and other Pascal compilers</li> 4549 <li><a href="mailto:aleksey@aleksey.com">Aleksey Sanin</a> implemented the 4550 <a href="http://www.w3.org/Signature/">XML Canonicalization and XML 4551 Digital Signature</a> <a 4552 href="http://www.aleksey.com/xmlsec/">implementations for libxml2</a></li> 4553 <li><a href="mailto:Steve.Ball@zveno.com">Steve Ball</a>, <a 4554 href="http://www.zveno.com/">Zveno</a> and contributors maintain <a 4555 href="http://tclxml.sourceforge.net/">tcl bindings for libxml2 and 4556 libxslt</a>, as well as <a 4557 href="http://tclxml.sf.net/tkxmllint.html">tkxmllint</a> a GUI for 4558 xmllint and <a href="http://tclxml.sf.net/tkxsltproc.html">tkxsltproc</a> 4559 a GUI for xsltproc.</li> 4560</ul> 4561 4562<p></p> 4563</body> 4564</html> 4565
