Re: [PyKDE] KHTML method returning null
Ah, problem solved! On Tuesday 06 March 2007 01:00, Jim Bublitz wrote: On Monday 05 March 2007 08:29, Paul Giannaros wrote: The documentation for KHTML's DOM::Document::getElementById ( http://api.kde.org/3.5-api/kdelibs-apidocs/khtml/html/classDOM_1_1Documen t. html#a20 ) show's that the method returns null when an element in the webpage by the given ID hasn't been found. I would have thought that would have mapped to Python's None, but instead I'm getting a khtml.DOM.Element. If the underlying C++ call returns null, the PyKDE call should return None (see sip_api_return_from_new_instance in siplib/siplib.c) Aha, I see. Whenever I try to call a method on it, my application crashes with terminate called after throwing an instance of 'DOM::DOMException'. Firstly, is this intended behaviour? I don't think so. Secondly, is there any way that I can check if the return value from that call is a valid object? Try accessing some method of the object, I suppose (you can also check its Python type, of course, but that only tells you what Python thinks the object is). I'd suggest posting a short example program that demonstrates the problem (include the html necessary to cause it too). Most of this stuff is straightforward sip wrappers - meaning sip generates the code the same as for any other C++ class, and there isn't anything unusual or customized that I can see. That suggests the most likely problem is in the implementation you're doing - the commonest problem is not keeping a Python reference to an object you're trying to access, for example. However the khtml, and especially DOM, stuff hasn't gotten a lot of use, and I have no application code to test it with, so problems either in PyKDE or the underlying KDE code are quite possible too. Either way, an example would be useful to see what's happening. Jim It turns out that it was a documentation / cognitive problem. The docs say it returns null, but it turns out it just returns a 'null element'. You can call isNull() on the returned object to check whether or not it's valid. Thanks Maybe there is something you can do with the sip module? (though I can't see anything in the docs) Thanks, Paul ___ PyKDE mailing listPyKDE@mats.imk.fraunhofer.de http://mats.imk.fraunhofer.de/mailman/listinfo/pykde ___ PyKDE mailing listPyKDE@mats.imk.fraunhofer.de http://mats.imk.fraunhofer.de/mailman/listinfo/pykde ___ PyKDE mailing listPyKDE@mats.imk.fraunhofer.de http://mats.imk.fraunhofer.de/mailman/listinfo/pykde
[PyKDE] KHTML method returning null
The documentation for KHTML's DOM::Document::getElementById ( http://api.kde.org/3.5-api/kdelibs-apidocs/khtml/html/classDOM_1_1Document.html#a20 ) show's that the method returns null when an element in the webpage by the given ID hasn't been found. I would have thought that would have mapped to Python's None, but instead I'm getting a khtml.DOM.Element. Whenever I try to call a method on it, my application crashes with terminate called after throwing an instance of 'DOM::DOMException'. Firstly, is this intended behaviour? Secondly, is there any way that I can check if the return value from that call is a valid object? Maybe there is something you can do with the sip module? (though I can't see anything in the docs) Thanks, Paul ___ PyKDE mailing listPyKDE@mats.imk.fraunhofer.de http://mats.imk.fraunhofer.de/mailman/listinfo/pykde
Re: [PyKDE] KHTML method returning null
On Monday 05 March 2007 08:29, Paul Giannaros wrote: The documentation for KHTML's DOM::Document::getElementById ( http://api.kde.org/3.5-api/kdelibs-apidocs/khtml/html/classDOM_1_1Document. html#a20 ) show's that the method returns null when an element in the webpage by the given ID hasn't been found. I would have thought that would have mapped to Python's None, but instead I'm getting a khtml.DOM.Element. If the underlying C++ call returns null, the PyKDE call should return None (see sip_api_return_from_new_instance in siplib/siplib.c) Whenever I try to call a method on it, my application crashes with terminate called after throwing an instance of 'DOM::DOMException'. Firstly, is this intended behaviour? I don't think so. Secondly, is there any way that I can check if the return value from that call is a valid object? Try accessing some method of the object, I suppose (you can also check its Python type, of course, but that only tells you what Python thinks the object is). I'd suggest posting a short example program that demonstrates the problem (include the html necessary to cause it too). Most of this stuff is straightforward sip wrappers - meaning sip generates the code the same as for any other C++ class, and there isn't anything unusual or customized that I can see. That suggests the most likely problem is in the implementation you're doing - the commonest problem is not keeping a Python reference to an object you're trying to access, for example. However the khtml, and especially DOM, stuff hasn't gotten a lot of use, and I have no application code to test it with, so problems either in PyKDE or the underlying KDE code are quite possible too. Either way, an example would be useful to see what's happening. Jim Maybe there is something you can do with the sip module? (though I can't see anything in the docs) Thanks, Paul ___ PyKDE mailing listPyKDE@mats.imk.fraunhofer.de http://mats.imk.fraunhofer.de/mailman/listinfo/pykde ___ PyKDE mailing listPyKDE@mats.imk.fraunhofer.de http://mats.imk.fraunhofer.de/mailman/listinfo/pykde
