pymulter 0.2.0

Python bindings for Rust multer library

pymulter

pymulter is a Python binding for the Rust library multer.

Note:
This module was created with the help of AI tools to bridge between Python and Rust.
I'm not a Rust developer, so feedback and contributions are appreciated!

Features

• Async Streaming Multipart Parsing: Efficiently parse multipart form data in a streaming fashion, suitable for large file uploads.
• Field Constraints: Restrict which fields are accepted using allowed_fields.
• Size Limits: Enforce limits on the whole stream, per field, or per field name.
• Typed API: Exposes clear Python classes for size limits, constraints, parser, and fields.
• Header Parsing Utility: Extract boundary from Content-Type headers.

Installation

Install from PyPI (recommended):

pip install pymulter
# or
uv add pymulter

For development (editable mode), use:

pip install maturin
maturin develop

Usage Example

NOTE:
pymulter is designed for advanced use cases where you need to process multipart/form-data uploads in an async, streaming fashion.

• You must use await with all async methods (feed, close, next_field, and iterating over fields).
• You are responsible for extracting the boundary from the Content-Type header using pymulter.parse_boundary.
• Data should be fed to the parser in bytes, and you can call feed multiple times as you receive data (e.g., from a network stream).
• After feeding all data, call await parser.close() before iterating fields.
• Each field is an async iterator yielding chunks of bytes.
• Use constraints (Constraint, SizeLimit) to restrict allowed fields or enforce size limits as needed.

See the example below for a typical usage pattern.

import pymulter

# Extract boundary from Content-Type header
type_header = "multipart/form-data; boundary=----WebKitFormBoundary7MA4YWxkTrZu0gW"
boundary = pymulter.parse_boundary(type_header)

# Create a parser (optionally with constraints)
parser = pymulter.MultipartParser(boundary)

# Feed data (can be called multiple times for streaming)
await parser.feed(b"--boundary...multipart body bytes...")
await parser.close()

# Iterate over fields
while True:
    field = await parser.next_field()
    if field is None:
        break
    print("Field name:", field.name)
    print("Filename:", field.filename)
    print("Content-Type:", field.content_type)
    print("Headers:", field.headers)
    data = b""
    async for chunk in field:
        data += chunk
    print("Data:", data)

Testing

Install test dependencies and run tests:

maturin develop -E tests
pytest