mimetypes and _winreg
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). Should I file this as a feature request?
Thanks
-Mike
from _winreg import HKEY_CLASSES_ROOT, OpenKey, EnumKey, QueryValueEx
i = 0 typemap = {} try: while 1: subkeyname = EnumKey(HKEY_CLASSES_ROOT, i) try: subkey = OpenKey(HKEY_CLASSES_ROOT, subkeyname) if subkeyname[:1] == '.': data = QueryValueEx(subkey, 'Content Type')[0] print subkeyname, '=', data typemap[subkeyname] = data # data will be unicode except EnvironmentError, WindowsError: pass i += 1 except WindowsError: pass
Mike Brown mike@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.
Thomas
Thomas Heller wrote:
Mike Brown mike@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.
Thomas
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
Following up on this 12 Jun 2004 post...
Garth wrote:
Thomas Heller wrote:
Mike Brown mike@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?
Sorry, but I really want access to registry subkeys to stop being so dog-slow. :)
Thanks for taking a look,
-Mike
Mike Brown mike@skew.org writes:
Following up on this 12 Jun 2004 post...
Garth wrote:
Thomas Heller wrote:
Mike Brown mike@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. http://www.python.org/sf/977553
Thomas
participants (3)
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Garth -
Mike Brown -
Thomas Heller