Registry / serialization / u-msgpack-python

u-msgpack-python

library2.8.0pypypi✓ verified 23d ago

u-msgpack-python is a lightweight MessagePack serializer and deserializer module written entirely in pure Python. It is compatible with both Python 2 and 3, as well as CPython and PyPy implementations, and fully complies with the latest MessagePack specification, including support for binary, UTF-8 string, application-defined ext, and timestamp types. The current version is 2.8.0, with releases occurring a few times per year to maintain compliance and add features.

serialization

pip install u-msgpack-python

github ↗package ↗

INSTALL

IMPORT

SIG · U-MSGPACK-PYTHON

u-msgpack-python

serializationpythonv2.8.0

Install

1.5s avg

Import

10ms

Disk

16MB

Pass rate

10/ 10

Env Coverage10 / 10

glibc

3.9–3.13

musl

3.9–3.13

Install & Compatibility

Where this runs

tested against v2.8.0 · pip install

no network on importno background threads

Install × environment matrix

Each cell = how many times install + import succeeded across repeated harness runs. Partial = flaky.
glibc = Debian/Ubuntu slim · musl = Alpine Linux

musl

py 3.10–3.95 runs

installs and imports cleanly · install 0.0s · import 0.002s · 17.9MB

glibc

py 3.10–3.95 runs

installs and imports cleanly · install 1.5s · import 0.000s · 18MB

16MB installed

● package 16MB

Code

Verified usage

Verified import paths — ran on the pinned version, not inferred.

umsgpack

✓ import umsgpack

✗ import u_msgpack_python

The package name on PyPI is `u-msgpack-python`, but the module to import is `umsgpack`.

This quickstart demonstrates how to pack Python objects into MessagePack bytes and unpack them. It also shows an example of streaming serialization and deserialization using file-like objects for multiple MessagePack objects.

import umsgpack data = {"name": "Alice", "age": 30, "is_student": False} # Serialize a Python object to MessagePack bytes packed_data = umsgpack.packb(data) print(f"Packed data: {packed_data}") # Deserialize MessagePack bytes back to a Python object unpacked_data = umsgpack.unpackb(packed_data) print(f"Unpacked data: {unpacked_data}") # Example with streaming to/from a file-like object from io import BytesIO f = BytesIO() umsgpack.pack({"compact": True, "schema": 0}, f) umsgpack.pack([1, 2, 3], f) f.seek(0) # Unpack multiple objects from the stream obj1 = umsgpack.unpack(f) obj2 = umsgpack.unpack(f) print(f"Object 1 from stream: {obj1}") print(f"Object 2 from stream: {obj2}")

Debug

Known issues

gotchaConfusing `u-msgpack-python` with the `msgpack` library (the CPython binding with fallback). While both handle MessagePack, `u-msgpack-python` is a pure Python implementation and may have subtle behavioral or performance differences. The `msgpack` library (on PyPI as `msgpack`) had significant breaking changes in its 1.0 release regarding Python 2 support, default binary/string handling, and removed encoding options. Users should be aware of which library they are using.

fix

Explicitly choose `u-msgpack-python` for a pure Python solution or `msgpack` for C extensions. Review the documentation for the chosen library to understand its specific behavior, especially concerning string/binary types and old MessagePack specification compatibility.

affects: All versions

gotchaHandling old MessagePack specification data. By default, `u-msgpack-python` is fully compliant with the latest MessagePack specification, which distinguishes between string and binary types. Older specifications used a single 'raw' type. If interacting with systems that generate old-spec MessagePack, you might need to enable `umsgpack.compatibility = True` or use specific packing/unpacking options.

fix

Set `umsgpack.compatibility = True` before packing/unpacking if you need to serialize both unicode strings and bytes into the old 'raw' type, or deserialize 'raw' into bytes. Be aware this is a global module setting.

affects: All versions

gotchaLoss of float precision during serialization. The `packb` and `pack` functions offer a `force_float_precision` option ('single' or 'double'). Using 'single' will force floats to be packed as IEEE-754 single-precision, which may result in a loss of precision if the original float was double-precision.

fix

Only use `force_float_precision='single'` when explicitly intending to reduce float precision for storage efficiency, and understand the implications. Otherwise, omit this option to retain default precision.

affects: All versions

Upgrade

Version history

2.8.0latest on PyPI · released May 18, 2023

Audit

Dependencies

No dependency data recorded yet.

Agent activity

10 hits · last 30 days

node

OpenAI (training)

Resources

githubhttps://github.com/vsergeev/u-msgpack-python ↗

packagehttps://pypi.org/project/u-msgpack-python/ ↗