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README.md 7.52 KiB

MessagePack for Python

Build Status Documentation Status

What's this

MessagePack is an efficient binary serialization format. It lets you exchange data among multiple languages like JSON. But it's faster and smaller. This package provides CPython bindings for reading and writing MessagePack data.

Very important notes for existing users

PyPI package name

Package name on PyPI was changed from msgpack-python to msgpack from 0.5.

When upgrading from msgpack-0.4 or earlier, do pip uninstall msgpack-python before pip install -U msgpack.

Compatibility with the old format

You can use use_bin_type=False option to pack bytes object into raw type in the old msgpack spec, instead of bin type in new msgpack spec.

You can unpack old msgpack format using raw=True option. It unpacks str (raw) type in msgpack into Python bytes.

See note below for detail.

Major breaking changes in msgpack 1.0

  • Python 2

    • The extension module does not support Python 2 anymore. The pure Python implementation (msgpack.fallback) is used for Python 2.

  • Packer

    • use_bin_type=True by default. bytes are encoded in bin type in msgpack. If you are still using Python 2, you must use unicode for all string types. You can use use_bin_type=False to encode into old msgpack format.
    • encoding option is removed. UTF-8 is used always.

  • Unpacker

    • raw=False by default. It assumes str types are valid UTF-8 string and decode them to Python str (unicode) object.
    • encoding option is removed. You can use raw=True to support old format.
    • Default value of max_buffer_size is changed from 0 to 100 MiB.
    • Default value of strict_map_key is changed to True to avoid hashdos. You need to pass strict_map_key=False if you have data which contain map keys which type is not bytes or str.

Install

$ pip install msgpack

Pure Python implementation

The extension module in msgpack (msgpack._cmsgpack) does not support Python 2 and PyPy.

But msgpack provides a pure Python implementation (msgpack.fallback) for PyPy and Python 2.

Windows