Parser for multipart/form-data

This module provides a parser for the multipart/form-data format. It can read from a file, a socket or a WSGI environment. The parser can be used to replace cgi.FieldStorage to work around its limitations.

Features

• Parses multipart/form-data and application/x-www-form-urlencoded.
• Produces useful error messages in 'strict'-mode.
• Gracefully handle uploads of unknown size (missing Content-Length header).
• Fast memory mapped files (io.BytesIO) for small uploads.
• Temporary files on disk for big uploads.
• Memory and disk resource limits to prevent DOS attacks.
• Fixes many shortcomings and bugs of cgi.FieldStorage.
• 100% test coverage.

Limitations

• Only parses multipart/form-data as seen from actual browsers.
  • Not suitable as a general purpose multipart parser (e.g. for multipart emails).
  • No multipart/mixed support (RFC 2388, deprecated in RFC 7578)
  • No encoded-word encoding (RFC 2047).
  • No base64 or quoted-printable transfer encoding.
• Part headers are expected to be encoded in the charset given to the Multipart/MultipartParser constructor. [For operability considerations, see RFC 7578, section 5.1.]
• The size of headers are not counted against the in-memory limit (todo).

Changelog

• unreleased * Gracefully handle CONTENT_LENGTH == ""
• 0.2.4 (27.01.2021) * Consistently decode non-utf8 URL-encoded form-data
• 0.2.3 (20.11.2020) * Import MutableMapping from collections.abc (#23) * Fix a few more ResourceWarnings in the test suite (#24) * Allow stream to contain data before first boundary (#25)
• 0.2.2 (04.09.2020) * Fix #21 ResourceWarnings on Python 3
• 0.2.1 (13.06.2020) * Fix #20 empty payload
• 0.2 (19.03.2019) * Dropped support for Python versions below 3.6. Stay on 0.1 if you need Python 2.5+ support.
• 0.1 (21.06.2010) * First release