1. Summary

It would be nice if Python will associate popular configuration extensions .yaml and .yml with the application/yaml media type.

2. Behavior

2.1. Current

>>> import mimetypes
>>> mimetypes.guess_file_type("KiraGoddess.yaml")
(None, None)
>>> mimetypes.guess_file_type("KiraGoddess.yml")
(None, None)

2.2. Desired

>>> import mimetypes
>>> mimetypes.guess_file_type("KiraGoddess.yaml")
('application/yaml', None)
>>> mimetypes.guess_file_type("KiraGoddess.yml")
('application/yaml', None)

3. Specifications

Comments in the mimetypes Python module:

RFC 9512 Abstract:

This document registers the application/yaml media type and the +yaml structured syntax suffix with IANA.

RFC 9512 “Filename Extension” section:

The "yaml" filename extension is the preferred one; it is the most popular and widely used on the web. The "yml" filename extension is still used. The simultaneous usage of two filename extensions in the same context might cause interoperability issues (e.g., when both a "config.yaml" and a "config.yml" are present).

IANA specification for application/yaml.

4. Has this already been discussed elsewhere?

Issue authors in this issue tracker write:

This is a minor feature, which does not need previous discussion elsewhere

Thanks.

Linked PRs

• gh-132054: Add application/yaml to mimetypes #132056