[Python-Dev] mimetypes and _winreg

Thomas Heller theller at python.net
Wed Feb 2 12:05:32 CET 2005

Mike Brown <mike at skew.org> writes:

> Following up on this 12 Jun 2004 post...
> Garth wrote:
>> Thomas Heller wrote:
>> >Mike Brown <mike at skew.org> writes:
>> >>I thought it would be nice to try to improve the mimetypes module by having 
>> >>it, on Windows, query the Registry to get the mapping of filename extensions 
>> >>to media types, since the mimetypes code currently just blindly checks 
>> >>posix-specific paths for httpd-style mapping files. However, it seems that the 
>> >>way to get mappings from the Windows registry is excessively slow in Python.
>> >>
>> >>I'm told that the reason has to do with the limited subset of APIs that are 
>> >>exposed in the _winreg module. I think it is that EnumKey(key, index) is 
>> >>querying for the entire list of subkeys for the given key every time you call 
>> >>it. Or something. Whatever the situation is, the code I tried below is way 
>> >>slower than I think it ought to be.
>> >>
>> >>Does anyone have any suggestions (besides "write it in C")? Could _winreg 
>> >>possibly be improved to provide an iterator or better interface to get the 
>> >>subkeys? (or certain ones? There are a lot of keys under HKEY_CLASSES_ROOT, 
>> >>and I only need the ones that start with a period).
>> >
>> >See this post I made some time ago:
>> ><http://mail.python.org/pipermail/python-dev/2004-January/042198.html>
>> >
>> >>Should I file this as a feature request?
>> >
>> >If you still think it should be changed in the core, you should work on
>> >a patch.
>> >
>> I could file a patch if no one else is looking at it. The solution would 
>> be to use RegEnumKeyEx and remove RegQueryInfoKey. This loses
>> compatability with win16 which I guess is ok.
>> Garth
> I would say it looks like no one else was looking at it, and Garth apparently 
> didn't submit a patch. It's beyond my means to come up with a patch myself. 
> Would someone be willing to take a look at it?

There is a patch, but, as so often, work on it has stalled.


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