python-multipart-rust

Stage-1 Rust mirror of Kludex/python-multipart (python-multipart 0.0.32, Apache-2.0): a streaming multipart parser for Python.

Boundary

The CPU hot path — the two byte-level state machines (MultipartParser._internal_write, QuerystringParser._internal_write) plus parse_options_header/_parseparam — lives in the reusable multipart-rust-core crate (no Python dependency) with a thin PyO3 binding (python_multipart._python_multipart). Everything else is the upstream source verbatim:

• ported to Rust: multipart + querystring state machines, options-header parsing;
• kept in Python: Field, File (file I/O + tempfile spooling), BaseParser, OctetStreamParser (no byte loop), FormParser, create_form_parser, parse_form, decoders, exceptions.

python_multipart/ keeps the exact public interface (including MultipartState/QuerystringState member identity and per-chunk error offsets); the legacy multipart/ alias package ships unchanged.

Build

python3 -m venv .venv && . .venv/bin/activate
pip install maturin
maturin develop --release
python3 -m pytest tests/ -q

Layout

• python_multipart-core/ — reusable Rust core (multipart-rust-core on crates.io).
• src/lib.rs — PyO3 binding (python_multipart._python_multipart).
• python_multipart/ — Python package (hot paths delegate to the core).
• multipart/ — legacy alias (upstream-verbatim).
• tests/ — upstream suite (frozen oracle; do not weaken).

Measured performance

No accepted optimizations yet (mirror baseline); re-run release-prep after run --stage optimize merges winners. Artifact hashes are intentionally absent here; see release-manifest.json.