Issue 22347: mimetypes.guess_type("//example.com") misinterprets host name as file name

The documentation says that guess_type() takes a URL, but:

>>> mimetypes.guess_type("http://example.com")
('application/x-msdownload', None)

I suspect the MS download is a reference to *.com files (like DOS's command.com). My current workaround is to strip out the host name from the URL, since I cannot imagine it would be useful for determining the content type. I am also stripping the fragment part. An argument could probably be made for stripping the “;parameters” and “?query” parts as well.

>>> # Workaround for mimetypes.guess_type("//example.com")
... # interpreting host name as file name
... url = urlparse("http://example.com")
>>> url = net.url_replace(url, netloc="", fragment="")
>>> url
'http://'
>>> mimetypes.guess_type(url, strict=False)
(None, None)

Posting a patch to fix this. It passes the URL through a urlsplit() → urlunsplit() stage, while removing the scheme://netloc parts.

The proposed patch I mentioned on bpo-35939 also solve the above situation.

Python 3.8.0a1+ (heads/bpo-12317:96d37dbcd2, Feb  8 2019, 12:03:40)
[Clang 9.1.0 (clang-902.0.39.1)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import mimetypes
>>> mimetypes.guess_type("http://example.com")
(None, None)
>>> mimetypes.guess_type("example.com")
('application/x-msdownload', None)
>>>

I've also added the unit tests of mimetypes-host.patch. It works well.
I think that we close this issue also when the bpo-35939 is closed.

Thanks alot!

New changeset 87bd2071c756188b6cd577889fb1682831142ceb by Miss Islington (bot) (Dong-hee Na) in branch 'master':
bpo-22347: Update mimetypes.guess_type to allow proper parsing of URLs (GH-15522)
https://github.com/python/cpython/commit/87bd2071c756188b6cd577889fb1682831142ceb

New changeset 6d7a786d2e4b48a6b50614e042ace9ff996f0238 by Miss Islington (bot) in branch '3.8':
bpo-22347: Update mimetypes.guess_type to allow proper parsing of URLs (GH-15522)
https://github.com/python/cpython/commit/6d7a786d2e4b48a6b50614e042ace9ff996f0238

New changeset 8873bff2871078e9f23e6c7d942d3a8edbd0921f by Miss Islington (bot) (Dong-hee Na) in branch '3.7':
[3.7] bpo-22347: Update mimetypes.guess_type to allow proper parsing of URLs (GH-15522) (GH-15687)
https://github.com/python/cpython/commit/8873bff2871078e9f23e6c7d942d3a8edbd0921f

@vstinner(my mentor) @maxking
Now this issue is solved.
I'd like to close this issue. Is it okay?

I think so, yes.

Also, while you are at it, can you also close bpo-35939 with a comment that points to this issue and the right PR for the fix?

Great! I will close bpo-35939 also.

This change introduces a potential 3.7 regression; see Issue38449.

New changeset 19a3d873005e5730eeabdc394c961e93f2ec02f0 by Miss Islington (bot) (Abhilash Raj) in branch 'master':
bpo-38449: Revert "bpo-22347: Update mimetypes.guess_type to allow oper parsing of URLs (GH-15522)" (GH-16724)
https://github.com/python/cpython/commit/19a3d873005e5730eeabdc394c961e93f2ec02f0

I am going to re-open this since the fixes were reverted in all the branches.

New changeset 5a638a805503131f4a9cc2bbc5944611295c1500 by Abhilash Raj in branch '3.8':
[3.8] bpo-38449: Revert "bpo-22347: Update mimetypes.guess_type to allow oper parsing of URLs" (GH-16724) (GH-16728)
https://github.com/python/cpython/commit/5a638a805503131f4a9cc2bbc5944611295c1500

New changeset 164bee296ab1f87cc05566b39ee8fb9fb64b3e5a by Miss Islington (bot) (Abhilash Raj) in branch '3.7':
[3.7] bpo-38449: Revert "bpo-22347: Update mimetypes.guess_type to allow oper parsing of URLs (GH-15685)" (GH-16724) (GH-16727)
https://github.com/python/cpython/commit/164bee296ab1f87cc05566b39ee8fb9fb64b3e5a

New changeset 2a405598bbccbc42710dc5ecf3d44c8de4c16582 by Ned Deily (Abhilash Raj) in branch '3.7':
[3.7] bpo-38449: Revert "bpo-22347: Update mimetypes.guess_type to allow oper parsing of URLs (GH-15685)" (GH-16724) (GH-16727)
https://github.com/python/cpython/commit/2a405598bbccbc42710dc5ecf3d44c8de4c16582

messages: + msg354535