zlib-rust

Python bindings for the Trifecta Tech Foundation's zlib-rs, a fast Rust implementation of zlib.

The foundation develops and maintains zlib-rs as part of its data compression initiative. The compression engine, its optimizations, and its Rust API are their work. This package brings that work to Python, with a familiar interface and installable wheels, independently of the library your Python distributor chose.

How to use

pip install zlib-rust

The public API follows Python's standard-library zlib module. The package imports as zlib_rust, so switching your own code is explicit:

import zlib_rust as zlib

compressed = zlib.compress(b"hello")
assert zlib.decompress(compressed) == b"hello"

Streaming compression and decompression use compressobj() and decompressobj(). Raw DEFLATE, zlib, and gzip streams are supported through the usual wbits parameter. Streaming decompression supports max_length to bound the output of each call.

For gzip files, use the familiar GzipFile and open() interfaces:

from zlib_rust.gzip import GzipFile

with GzipFile("events.gz", "wb") as stream:
    stream.write(b"hello\n")

The file-handling code comes from CPython's gzip module, using zlib-rs for compression, decompression, and checksums. Both checksum-combine functions are available on every supported Python version.

The binding forbids unsafe Rust and releases the GIL during codec operations. Package versions follow the pinned zlib-rs crate version.

Development

Install Rust 1.85 or newer and Python 3.11 or newer. Build a wheel with maturin build --release --locked, install it into your development environment, then run pytest.

This package was built with heavy use of LLMs. Its tests combine CPython's zlib and gzip suites with interoperability tests against the standard-library codec and tests for the Python binding. Imported tests retain their source references and documented adaptations.

The Trifecta Tech Foundation's work makes this package possible. You can support the foundation to help sustain zlib-rs and its other public-interest infrastructure projects.

Alternatives (Python 3.16, conditions apply)

From Python 3.16 onwards you can also use zlib-rs through Python's standard-library zlib module. CPython 3.16 adds a --with-zlib=zlib-rs build option.

That's great, but Python 3.16 doesn't exist yet, and you'd depend on the choices of your Python distributor (often: Linux distributions, container images, or Python installers).

This package lets you select zlib-rs for your own code while using an existing Python installation, including older Python versions.