* This entity generator comforms to the entity transfer rules outlined in the * Section 4.4, * Section 3.6, * Section 14.41 * and Section 14.13 * of RFC 2616 *
** The transfer-length of a message is the length of the message-body as it appears in the * message; that is, after any transfer-codings have been applied. When a message-body is * included with a message, the transfer-length of that body is determined by one of the * following (in order of precedence): *
** 1.Any response message which "MUST NOT" include a message-body (such as the 1xx, 204, * and 304 responses and any response to a HEAD request) is always terminated by the first * empty line after the header fields, regardless of the entity-header fields present in the * message. *
** 2.If a Transfer-Encoding header field (section 14.41) is present and has any value other * than "identity", then the transfer-length is defined by use of the "chunked" transfer- * coding (section 3.6), unless the message is terminated by closing the connection. *
** 3.If a Content-Length header field (section 14.13) is present, its decimal value in * OCTETs represents both the entity-length and the transfer-length. The Content-Length * header field MUST NOT be sent if these two lengths are different (i.e., if a * Transfer-Encoding *
** header field is present). If a message is received with both a * Transfer-Encoding header field and a Content-Length header field, * the latter MUST be ignored. **
* 4.If the message uses the media type "multipart/byteranges", and the ransfer-length is not * otherwise specified, then this self- elimiting media type defines the transfer-length. * This media type UST NOT be used unless the sender knows that the recipient can arse it; the * presence in a request of a Range header with ultiple byte- range specifiers from a 1.1 * client implies that the lient can parse multipart/byteranges responses. *
** A range header might be forwarded by a 1.0 proxy that does not * understand multipart/byteranges; in this case the server MUST * delimit the message using methods defined in items 1,3 or 5 of * this section. **
* 5.By the server closing the connection. (Closing the connection cannot be used to indicate * the end of a request body, since that would leave no possibility for the server to send back * a response.) *
** For compatibility with HTTP/1.0 applications, HTTP/1.1 requests containing a message-body * MUST include a valid Content-Length header field unless the server is known to be HTTP/1.1 * compliant. If a request contains a message-body and a Content-Length is not given, the * server SHOULD respond with 400 (bad request) if it cannot determine the length of the * message, or with 411 (length required) if it wishes to insist on receiving a valid * Content-Length. *
*All HTTP/1.1 applications that receive entities MUST accept the "chunked" transfer-coding * (section 3.6), thus allowing this mechanism to be used for messages when the message * length cannot be determined in advance. *
** Transfer-coding values are used to indicate an encoding transformation that * has been, can be, or may need to be applied to an entity-body in order to ensure * "safe transport" through the network. This differs from a content coding in that * the transfer-coding is a property of the message, not of the original entity. *
** transfer-coding = "chunked" | transfer-extension * transfer-extension = token *( ";" parameter ) **
* Parameters are in the form of attribute/value pairs. *
** parameter = attribute "=" value * attribute = token * value = token | quoted-string **
* All transfer-coding values are case-insensitive. HTTP/1.1 uses transfer-coding values in * the TE header field (section 14.39) and in the Transfer-Encoding header field (section 14.41). *
** Whenever a transfer-coding is applied to a message-body, the set of transfer-codings MUST * include "chunked", unless the message is terminated by closing the connection. When the * "chunked" transfer-coding is used, it MUST be the last transfer-coding applied to the * message-body. The "chunked" transfer-coding MUST NOT be applied more than once to a * message-body. These rules allow the recipient to determine the transfer-length of the * message (section 4.4). *
** The Transfer-Encoding general-header field indicates what (if any) type of transformation has * been applied to the message body in order to safely transfer it between the sender and the * recipient. This differs from the content-coding in that the transfer-coding is a property of * the message, not of the entity. *
** Transfer-Encoding = "Transfer-Encoding" ":" 1#transfer-coding **
* If multiple encodings have been applied to an entity, the transfer- codings MUST be listed in * the order in which they were applied. Additional information about the encoding parameters * MAY be provided by other entity-header fields not defined by this specification. *
** The Content-Length entity-header field indicates the size of the entity-body, in decimal * number of OCTETs, sent to the recipient or, in the case of the HEAD method, the size of * the entity-body that would have been sent had the request been a GET. *
** Content-Length = "Content-Length" ":" 1*DIGIT **
* Applications SHOULD use this field to indicate the transfer-length of the message-body, * unless this is prohibited by the rules in section 4.4. *
* * @author Oleg Kalnichevski * * @version $Revision: 573949 $ * * @since 4.0 */ public class StrictContentLengthStrategy implements ContentLengthStrategy { public StrictContentLengthStrategy() { super(); } public long determineLength(final HttpMessage message) throws HttpException { if (message == null) { throw new IllegalArgumentException("HTTP message may not be null"); } // Although Transfer-Encoding is specified as a list, in practice // it is either missing or has the single value "chunked". So we // treat it as a single-valued header here. Header transferEncodingHeader = message.getFirstHeader(HTTP.TRANSFER_ENCODING); Header contentLengthHeader = message.getFirstHeader(HTTP.CONTENT_LEN); if (transferEncodingHeader != null) { String s = transferEncodingHeader.getValue(); if (HTTP.CHUNK_CODING.equalsIgnoreCase(s)) { if (message.getProtocolVersion().lessEquals(HttpVersion.HTTP_1_0)) { throw new ProtocolException( "Chunked transfer encoding not allowed for " + message.getProtocolVersion()); } return CHUNKED; } else if (HTTP.IDENTITY_CODING.equalsIgnoreCase(s)) { return IDENTITY; } else { throw new ProtocolException( "Unsupported transfer encoding: " + s); } } else if (contentLengthHeader != null) { String s = contentLengthHeader.getValue(); try { long len = Long.parseLong(s); return len; } catch (NumberFormatException e) { throw new ProtocolException("Invalid content length: " + s); } } else { return IDENTITY; } } }