A problem with convertToData in nevow.accessors
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 I'm starting work on an app and ran into an odd little problem, and while in general I'd love to hack around on nevow to figure out exactly where its arising I need to go to sleep now, and would like to be able to progress on my project come tomorrow. Basically, I've got a data function that returns a Deferred (from the adbapi dbpool's runQuery method)-- that seems to get handled just fine - -- which is used for a sequence rendering. However, in the function convertToData in accessors.py, an error occurs: (nevow is just checked out from CVS, twisted is checked out from CVS a few days ago. I did install Nevow in site-packages, but I don't think that would be causing this). 2004/03/25 21:57 CST [-] FAILURE ! [Failure instance: Traceback: exceptions.AttributeError, ListContainer instance has no attribute 'get' 2004/03/25 21:57 CST [-] /System/Library/Frameworks/Python.framework/Versions/2.3/lib/python2.3/ site-packages/twisted/internet/defer.py:338:_runCallbacks 2004/03/25 21:57 CST [-] /System/Library/Frameworks/Python.framework/Versions/2.3/lib/python2.3/ site-packages/nevow/accessors.py:15:convertToData After educating myself somewhat on interfaces, I changed the code to help me debug the issue: def convertToData(data, context): from twisted.python import log log.err('data: ' + str(data)) log.err('data type: ' + str(type(data))) newdata = IGettable(data, persist=False, default=None) log.err('newdata: ' + str(newdata)) if newdata is not None: newdata = newdata.get(context) if isinstance(newdata, Deferred): return newdata.addCallback(convertToData, context) else: return convertToData(newdata, context) else: return data (original function was: def convertToData(data, context): newdata = IGettable(data, persist=False, default=None) if newdata is not None: newdata = newdata.get(context) if isinstance(newdata, Deferred): return newdata.addCallback(convertToData, context) else: return convertToData(newdata, context) else: return data ) Well, that produced some semi-mystifying results: 2004/03/25 21:57 CST [-] "data: [['samson and delilah', 'delilah and frank']]" 2004/03/25 21:57 CST [-] "data type: <type 'list'>" 2004/03/25 21:57 CST [-] 'newdata: <nevow.accessors.ListContainer instance at 0x111d968>' 2004/03/25 21:57 CST [-] FAILURE ! [Failure instance: Traceback: exceptions.AttributeError, ListContainer instance has no attribute 'get' 2004/03/25 21:57 CST [-] /System/Library/Frameworks/Python.framework/Versions/2.3/lib/python2.3/ site-packages/twisted/internet/defer.py:338:_runCallbacks 2004/03/25 21:57 CST [-] /System/Library/Frameworks/Python.framework/Versions/2.3/lib/python2.3/ site-packages/nevow/accessors.py:19:convertToData My guess is that IGettable is in this case supposed to return the None of the default argument, and thus the list itself be returned, but I'm not absolutely certain of that, and if that is what's supposed to happen, I'm in the dark as to why its not happening, and would need to peruse how Nevow handles interfaces a fair amount more, I think. -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.4 (Darwin) iD8DBQFAY61qFZO4LxR6+NgRAnE5AJ0TrpTFHOqJ/jP2yjAiz8pbpSgg2gCfXYtz uqLcFj09SklpstYAKdRNZh4= =yIwf -----END PGP SIGNATURE-----
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 I created a quick workaround by just checking if data is a list and if so returning it before the IGettable call. Its a hack, but it works well enough for now as all my Deferred db calls for data will return lists. On Mar 25, 2004, at 10:11 PM, Russell Duhon wrote:
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I'm starting work on an app and ran into an odd little problem, and while in general I'd love to hack around on nevow to figure out exactly where its arising I need to go to sleep now, and would like to be able to progress on my project come tomorrow.
Basically, I've got a data function that returns a Deferred (from the adbapi dbpool's runQuery method)-- that seems to get handled just fine - -- which is used for a sequence rendering. However, in the function convertToData in accessors.py, an error occurs:
(nevow is just checked out from CVS, twisted is checked out from CVS a few days ago. I did install Nevow in site-packages, but I don't think that would be causing this).
2004/03/25 21:57 CST [-] FAILURE ! [Failure instance: Traceback: exceptions.AttributeError, ListContainer instance has no attribute 'get' 2004/03/25 21:57 CST [-] /System/Library/Frameworks/Python.framework/Versions/2.3/lib/ python2.3/site-packages/twisted/internet/defer.py:338:_runCallbacks 2004/03/25 21:57 CST [-] /System/Library/Frameworks/Python.framework/Versions/2.3/lib/ python2.3/site-packages/nevow/accessors.py:15:convertToData
After educating myself somewhat on interfaces, I changed the code to help me debug the issue:
def convertToData(data, context): from twisted.python import log log.err('data: ' + str(data)) log.err('data type: ' + str(type(data))) newdata = IGettable(data, persist=False, default=None) log.err('newdata: ' + str(newdata)) if newdata is not None: newdata = newdata.get(context) if isinstance(newdata, Deferred): return newdata.addCallback(convertToData, context) else: return convertToData(newdata, context) else: return data
(original function was:
def convertToData(data, context): newdata = IGettable(data, persist=False, default=None) if newdata is not None: newdata = newdata.get(context) if isinstance(newdata, Deferred): return newdata.addCallback(convertToData, context) else: return convertToData(newdata, context) else: return data )
Well, that produced some semi-mystifying results:
2004/03/25 21:57 CST [-] "data: [['samson and delilah', 'delilah and frank']]" 2004/03/25 21:57 CST [-] "data type: <type 'list'>" 2004/03/25 21:57 CST [-] 'newdata: <nevow.accessors.ListContainer instance at 0x111d968>' 2004/03/25 21:57 CST [-] FAILURE ! [Failure instance: Traceback: exceptions.AttributeError, ListContainer instance has no attribute 'get' 2004/03/25 21:57 CST [-] /System/Library/Frameworks/Python.framework/Versions/2.3/lib/ python2.3/site-packages/twisted/internet/defer.py:338:_runCallbacks 2004/03/25 21:57 CST [-] /System/Library/Frameworks/Python.framework/Versions/2.3/lib/ python2.3/site-packages/nevow/accessors.py:19:convertToData
My guess is that IGettable is in this case supposed to return the None of the default argument, and thus the list itself be returned, but I'm not absolutely certain of that, and if that is what's supposed to happen, I'm in the dark as to why its not happening, and would need to peruse how Nevow handles interfaces a fair amount more, I think. -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.4 (Darwin)
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On Mar 25, 2004, at 11:11 PM, Russell Duhon wrote:
I'm starting work on an app and ran into an odd little problem, and while in general I'd love to hack around on nevow to figure out exactly where its arising I need to go to sleep now, and would like to be able to progress on my project come tomorrow.
Basically, I've got a data function that returns a Deferred (from the adbapi dbpool's runQuery method)-- that seems to get handled just fine - -- which is used for a sequence rendering. However, in the function convertToData in accessors.py, an error occurs:
(nevow is just checked out from CVS, twisted is checked out from CVS a few days ago. I did install Nevow in site-packages, but I don't think that would be causing this).
Looks to me like you've somehow mixed new nevow code with older nevow code. Older versions had an adapter from list to IGettable but current code does not. James
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Its got to be something with having installed in site-packages over an old version, then. I'll try rooting it out and reinstalling. *tries* Yeah, all fixed. *hits self on head* doh! On Mar 26, 2004, at 9:25 AM, James Y Knight wrote:
On Mar 25, 2004, at 11:11 PM, Russell Duhon wrote:
I'm starting work on an app and ran into an odd little problem, and while in general I'd love to hack around on nevow to figure out exactly where its arising I need to go to sleep now, and would like to be able to progress on my project come tomorrow.
Basically, I've got a data function that returns a Deferred (from the adbapi dbpool's runQuery method)-- that seems to get handled just fine - -- which is used for a sequence rendering. However, in the function convertToData in accessors.py, an error occurs:
(nevow is just checked out from CVS, twisted is checked out from CVS a few days ago. I did install Nevow in site-packages, but I don't think that would be causing this).
Looks to me like you've somehow mixed new nevow code with older nevow code. Older versions had an adapter from list to IGettable but current code does not.
James
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participants (2)
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James Y Knight -
Russell Duhon