mimetypes module does not recognize jp2 type

[naro]

BPO	41791
Nosy	@naro, @iritkatriel

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

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GitHub fields:

assignee = None
closed_at = None
created_at = <Date 2020-09-15.04:31:47.953>
labels = ['type-feature', '3.11']
title = 'mimetypes module does not recognize jp2 type'
updated_at = <Date 2022-01-19.00:38:51.433>
user = 'https://github.com/naro'

bugs.python.org fields:

activity = <Date 2022-01-19.00:38:51.433>
actor = 'adelfino'
assignee = 'none'
closed = False
closed_date = None
closer = None
components = []
creation = <Date 2020-09-15.04:31:47.953>
creator = 'naro'
dependencies = []
files = []
hgrepos = []
issue_num = 41791
keywords = []
message_count = 5.0
messages = ['376927', '377074', '377086', '377113', '410860']
nosy_count = 2.0
nosy_names = ['naro', 'iritkatriel']
pr_nums = []
priority = 'normal'
resolution = None
stage = None
status = 'open'
superseder = None
type = 'enhancement'
url = 'https://bugs.python.org/issue41791'
versions = ['Python 3.11']

Linked PRs

• gh-85957: Add missing MIME types for images with RFCs #126966

[naro]

Even if jp2 is in the official list of types https://www.iana.org/assignments/media-types/media-types.xhtml it's not recognized by the MimeTypes.guess_type:

>>> from mimetypes import MimeTypes
>>> MimeTypes().guess_type('test.jp2')
(None, None)

The same example works in Python 3.7 and returns 'image/jp2'

[andresdelfino]

Hi, Radim!

I've tested with 3.7.8 and got (None, None). I'm curious on how you got that 'image/jp2' output.

It seems jp2 was never supported by looking into the git history of Lib/mimetypes.py.

Would you like to open a PR to support it? :)

[naro]

Hi Andrés,

tried again and the difference is between 3.7.4 and 3.7.5
The jp2 mimetype is read from /etc/apache2/mime.types (see knownfiles in mimetypes.py) so the mime type does not have to be in the mimetypes.py hardcoded, but in version 3.7.5 it stopped working.

I think it's because of using _types_map_default instead of types_map in some places.

Since jp2 is an official mime type it should be added to the list but I also think we should try to identify the issue with _types_map_default.

Seems to be related to https://bugs.python.org/issue4963

I will have look if I can find out what was changed and why.

Cheers,
Radim

[andresdelfino]

Nice debugging!

[iritkatriel]

It is found by the module-level guess_type but not by the MimeType class's guess_type:

>>> from mimetypes import MimeTypes
>>> MimeTypes().guess_type('test.jp2')
(None, None)
>>> import mimetypes
>>> mimetypes.guess_type('test.jp2')
('image/jp2', None)
>>> 

That difference is the subject of bpo-38656.

What remains to decide here is whether jp2 should be added to the builtin list of mimetypes.