FileField not properly serializing to XML

[Chris Henderson <chris@…>]

When executing python manage.py dumpdata --format xml, FileField fields get serialized using the get_FIELD_url() method, which is causing (for me at least) this error:

Problem installing fixture 'myfixture.xml': [Errno 2] No such file or directory: u'/site_media/avatars/system/001.gif

The small attached patch fixes this problem by not treating FileField fields differently than other fields.

[Russell Keith-Magee]

I can't reproduce the problem you describe. Furthermore, the serializers regressiontest includes cases that serialize FileFields with no actual file present.

If you can provide a sample model, fixture, and test procedure, feel free to reopen this ticket.

[anonymous]

The issue isn't on serializing, but on trying to reload the info.

The serializer code calls get_fieldname_url instead of just outputting the database value:

        elif isinstance(field, models.FileField):
            value = getattr(obj, "get_%s_url" % field.name, lambda: None)()

So when you read it back in, it's got the wrong value - in his example, while the field originally held "avatars/system/001.gif", the serializers output "/site_media/avatars/system/001.gif"

[Collin Grady]

Er, the issue seems to only show up in the XML serializer, now that I look (that last comment was me btw)

[Chris Henderson <chris@…>]

The "no such file or directory" error I was getting and was noted in the report was actually related to a method being called from a pre_save signal being sent to resize an image, but the underlying problem does seem to be that the value in the database is changed as cgrady noted above. Sorry for the confusing report, but I do think that there is an actual problem in the XML serializer (which is calling the base serializer for this behavior).

[Marty Alchin]

After further research, I think this ticket is best dealt with as part of serialization, rather than in #5361.

[prairiedogg]

Jacob Kaplan-Moss said that this was OK to check in even though it does not have a test. I confirmed that running this patch against the full django test suite did not produce errors, and also that it fixed the bug in my production case.

[Malcolm Tredinnick]

(In [7293]) Fixed #5574 -- Serialize a FileField using its filename from the database, not
external URL. The problem showed up when reloading the data. Patch from Chris
Henderson.