README.md
1Protocol Buffers - Google's data interchange format
2===================================================
3
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5
6Copyright 2008 Google Inc.
7
8This directory contains the Python Protocol Buffers runtime library.
9
10Normally, this directory comes as part of the protobuf package, available
11from:
12
13 https://developers.google.com/protocol-buffers/
14
15The complete package includes the C++ source code, which includes the
16Protocol Compiler (protoc). If you downloaded this package from PyPI
17or some other Python-specific source, you may have received only the
18Python part of the code. In this case, you will need to obtain the
19Protocol Compiler from some other source before you can use this
20package.
21
22Development Warning
23===================
24
25The pure python performance is slow. For better preformance please
26use python c++ implementation.
27
28Installation
29============
30
311) Make sure you have Python 2.7 or newer. If in doubt, run:
32
33 $ python -V
34
352) If you do not have setuptools installed, note that it will be
36 downloaded and installed automatically as soon as you run `setup.py`.
37 If you would rather install it manually, you may do so by following
38 the instructions on [this page](https://packaging.python.org/en/latest/installing.html#setup-for-installing-packages).
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) Build and run the tests:
47
48 $ python setup.py build
49 $ python setup.py test
50
51 To build, test, and use the C++ implementation, you must first compile
52 `libprotobuf.so`:
53
54 $ (cd .. && make)
55
56 On OS X:
57
58 If you are running a Homebrew-provided Python, you must make sure another
59 version of protobuf is not already installed, as Homebrew's Python will
60 search `/usr/local/lib` for `libprotobuf.so` before it searches
61 `../src/.libs`.
62
63 You can either unlink Homebrew's protobuf or install the `libprotobuf` you
64 built earlier:
65
66 $ brew unlink protobuf
67
68 or
69
70 $ (cd .. && make install)
71
72 On other *nix:
73
74 You must make `libprotobuf.so` dynamically available. You can either
75 install libprotobuf you built earlier, or set `LD_LIBRARY_PATH`:
76
77 $ export LD_LIBRARY_PATH=../src/.libs
78
79 or
80
81 $ (cd .. && make install)
82
83 To build the C++ implementation run:
84
85 $ python setup.py build --cpp_implementation
86
87 Then run the tests like so:
88
89 $ python setup.py test --cpp_implementation
90
91 If some tests fail, this library may not work correctly on your
92 system. Continue at your own risk.
93
94 Please note that there is a known problem with some versions of
95 Python on Cygwin which causes the tests to fail after printing the
96 error: `sem_init: Resource temporarily unavailable`. This appears
97 to be a [bug either in Cygwin or in
98 Python](http://www.cygwin.com/ml/cygwin/2005-07/msg01378.html).
99
100 We do not know if or when it might be fixed. We also do not know
101 how likely it is that this bug will affect users in practice.
102
1035) Install:
104
105 $ python setup.py install
106
107 or:
108
109 $ (cd .. && make install)
110 $ python setup.py install --cpp_implementation
111
112 This step may require superuser privileges.
113 NOTE: To use C++ implementation, you need to export an environment
114 variable before running your program. See the "C++ Implementation"
115 section below for more details.
116
117Usage
118=====
119
120The complete documentation for Protocol Buffers is available via the
121web at:
122
123 https://developers.google.com/protocol-buffers/
124
125C++ Implementation
126==================
127
128The C++ implementation for Python messages is built as a Python extension to
129improve the overall protobuf Python performance.
130
131To use the C++ implementation, you need to install the C++ protobuf runtime
132library, please see instructions in the parent directory.
133
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