README.txt
1Protocol Buffers - Google's data interchange format
2Copyright 2008 Google Inc.
3
4This directory contains the Python Protocol Buffers runtime library.
5
6Normally, this directory comes as part of the protobuf package, available
7from:
8
9 http://code.google.com/p/protobuf
10
11The complete package includes the C++ source code, which includes the
12Protocol Compiler (protoc). If you downloaded this package from PyPI
13or some other Python-specific source, you may have received only the
14Python part of the code. In this case, you will need to obtain the
15Protocol Compiler from some other source before you can use this
16package.
17
18Development Warning
19===================
20
21The Python implementation of Protocol Buffers is not as mature as the C++
22and Java implementations. It may be more buggy, and it is known to be
23pretty slow at this time. If you would like to help fix these issues,
24join the Protocol Buffers discussion list and let us know!
25
26Installation
27============
28
291) Make sure you have Python 2.4 or newer. If in doubt, run:
30
31 $ python -V
32
332) If you do not have setuptools installed, note that it will be
34 downloaded and installed automatically as soon as you run setup.py.
35 If you would rather install it manually, you may do so by following
36 the instructions on this page:
37
38 http://peak.telecommunity.com/DevCenter/EasyInstall#installation-instructions
39
403) Build the C++ code, or install a binary distribution of protoc. If
41 you install a binary distribution, make sure that it is the same
42 version as this package. If in doubt, run:
43
44 $ protoc --version
45
464) Run the tests:
47
48 $ python setup.py test
49
50 If some tests fail, this library may not work correctly on your
51 system. Continue at your own risk.
52
53 Please note that there is a known problem with some versions of
54 Python on Cygwin which causes the tests to fail after printing the
55 error: "sem_init: Resource temporarily unavailable". This appears
56 to be a bug either in Cygwin or in Python:
57 http://www.cygwin.com/ml/cygwin/2005-07/msg01378.html
58 We do not know if or when it might me fixed. We also do not know
59 how likely it is that this bug will affect users in practice.
60
615) Install:
62
63 $ python setup.py install
64
65 This step may require superuser privileges.
66 NOTE: To use C++ implementation, you need to install C++ protobuf runtime
67 library of the same version and export the environment variable before this
68 step. See the "C++ Implementation" section below for more details.
69
70Usage
71=====
72
73The complete documentation for Protocol Buffers is available via the
74web at:
75
76 http://code.google.com/apis/protocolbuffers/
77
78C++ Implementation
79==================
80
81WARNING: This is EXPERIMENTAL and only available for CPython platforms.
82
83The C++ implementation for Python messages is built as a Python extension to
84improve the overall protobuf Python performance.
85
86To use the C++ implementation, you need to:
871) Install the C++ protobuf runtime library, please see instructions in the
88 parent directory.
892) Export an environment variable:
90
91 $ export PROTOCOL_BUFFERS_PYTHON_IMPLEMENTATION=cpp
92
93You need to export this variable before running setup.py script to build and
94install the extension. You must also set the variable at runtime, otherwise
95the pure-Python implementation will be used. In a future release, we will
96change the default so that C++ implementation is used whenever it is available.
97It is strongly recommended to run `python setup.py test` after setting the
98variable to "cpp", so the tests will be against C++ implemented Python
99messages.
100
101