Description

assignee = None
closed_at = None
created_at = <Date 2021-03-18.15:49:43.313>
labels = ['3.8', '3.9', '3.10']
title = 'mimetype default list make a wrong guess for illustrator file'
updated_at = <Date 2021-03-20.01:55:14.300>
user = 'https://github.com/inkhey'

activity = <Date 2021-03-20.01:55:14.300>
actor = 'terry.reedy'
assignee = 'none'
closed = False
closed_date = None
closer = None
components = []
creation = <Date 2021-03-18.15:49:43.313>
creator = 'Inkhey'
dependencies = []
files = []
hgrepos = []
issue_num = 43544
keywords = []
message_count = 1.0
messages = ['389023']
nosy_count = 1.0
nosy_names = ['Inkhey']
pr_nums = []
priority = 'normal'
resolution = None
stage = None
status = 'open'
superseder = None
type = None
url = 'https://bugs.python.org/issue43544'
versions = ['Python 3.8', 'Python 3.9', 'Python 3.10']

Activity

1. inkhey commented on Mar 18, 2021

   

   inkheymannequin

   on Mar 18, 2021

   MannequinAuthor

   More actions

   mimetypes lib consider illustrator file ('.ai') as 'application/postscript' type. This is correct... but also wrong.

   Old illustrator file (illustrator 9) are real postscript file but modern one are technically pdf. So guessing .ai as postscript lead to wrong guessing if you're using some software that make decision based on mimetype, you can of course, check both file_extension and mimetype but this remove usefulness of mimetype.
2. inkhey

   added

   3.7 (EOL)end of lifeend of life

   3.10 (EOL)end of lifeend of life

   3.8 (EOL)end of lifeend of life

   3.9 (EOL)end of lifeend of life

   on Mar 18, 2021
3. terryjreedy

   removed

   3.7 (EOL)end of lifeend of life

   on Mar 20, 2021
4. ezio-melotti

   transferred this issue fromon Apr 10, 2022
5. iritkatriel

   added

   stdlibStandard Library Python modules in the Lib/ directoryStandard Library Python modules in the Lib/ directory

   on Nov 27, 2023
6. StanFromIreland

   removed

   3.10 (EOL)end of lifeend of life

   3.9 (EOL)end of lifeend of life

   3.8 (EOL)end of lifeend of life

   on Oct 11, 2025
7. picnixz

   added

   type-featureA feature request or enhancementA feature request or enhancement

   on Oct 11, 2025
8. StanFromIreland

   self-assigned this

   on Nov 7, 2025
9. StanFromIreland commented on Nov 8, 2025

   

   StanFromIreland

   on Nov 8, 2025

   Member

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   Unfortunately the user is a mannequin. This is quite problematic, since we don't check contents like other mimetype checkers, there is no way of knowing if it is a new .ai file or an old one.

   Although, since the last version of AI to produce postscript files was released 25 years ago (see here), it can be assumed that the majority of files are now the modern PDF variation, and so IMO it makes sense to update it.
10. hugovk

    added a commit that references this issue on Nov 12, 2025

    gh-87710: Update mime type for ``.ai`` (#141239)

    88aeff8
11. hugovk commented on Nov 12, 2025

    

    hugovk

    on Nov 12, 2025

    Member

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    Thanks @inkhey and @StanFromIreland!
12. hugovk

    closed this as completedon Nov 12, 2025
13. aapa commented on Nov 12, 2025

    

    aapa

    on Nov 12, 2025

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    This Adobe documentation page (see the heading § Create PDF Compatible File option) seems to suggest that the PDF compatibility is an option, not a feature of the format itself. That would make the application/pdf filetype wrong. I don't have access to Adobe Illustrator to confirm what the resulting file looks like without the setting enabled, but this comment on Adobe Forums seems to suggest it's merely a PDF wrapper not viewable in any PDF standards supporting viewer. Yes, you probably still get more useful data out of it treating it as a PDF file instead of as a "traditional" Postscript file (I presume it would still have XMP data, for example), but it's still not PDF as defined by the PDF standards either. So something like application/vnd.adobe.illustrator or just the very nondescript but techically correct application/postscript would still be a better option IMO.
14. StanFromIreland

    added a commit that references this issue on Dec 6, 2025

    pythongh-87710: Update mime type for ``.ai`` (python#141239)

    19acff4

Issue actions