Django weird behavior with model containing ImageField

Question

I am facing a really strange behavior with my Photo model, containing a ImageField.

When I execute the following piece of code:

photos = Photo.objects.all()
for p in photos:
  print p.id

I get this error after Django displayed about 36680 ids :

Traceback (most recent call last):
  File "/Library/Python/2.7/site-packages/django/core/handlers/base.py", line 115, in get_response
    response = callback(request, *callback_args, **callback_kwargs)
  File "/Library/Python/2.7/site-packages/django/contrib/auth/decorators.py", line 25, in _wrapped_view
    return view_func(request, *args, **kwargs)
  File "/Users/me/Sites/django/mysite/forum/views.py", line 286, in photos_search
    for p in photos:
  File "/Library/Python/2.7/site-packages/django/db/models/query.py", line 139, in _result_iter
    self._fill_cache()
  File "/Library/Python/2.7/site-packages/django/db/models/query.py", line 941, in _fill_cache
    self._result_cache.append(next(self._iter))
  File "/Library/Python/2.7/site-packages/django/db/models/query.py", line 327, in iterator
    obj = model(*row_data)
  File "/Library/Python/2.7/site-packages/django/db/models/base.py", line 417, in __init__
    signals.post_init.send(sender=self.__class__, instance=self)
  File "/Library/Python/2.7/site-packages/django/dispatch/dispatcher.py", line 170, in send
    response = receiver(signal=self, sender=sender, **named)
  File "/Library/Python/2.7/site-packages/django/db/models/fields/files.py", line 379, in update_dimension_fields
    width = file.width
  File "/Library/Python/2.7/site-packages/django/core/files/images.py", line 15, in _get_width
    return self._get_image_dimensions()[0]
  File "/Library/Python/2.7/site-packages/django/core/files/images.py", line 25, in _get_image_dimensions
    self.open()
  File "/Library/Python/2.7/site-packages/django/db/models/fields/files.py", line 76, in open
    self.file.open(mode)
  File "/Library/Python/2.7/site-packages/django/db/models/fields/files.py", line 46, in _get_file
    self._file = self.storage.open(self.name, 'rb')
  File "/Library/Python/2.7/site-packages/django/core/files/storage.py", line 36, in open
    return self._open(name, mode)
  File "/Library/Python/2.7/site-packages/django/core/files/storage.py", line 159, in _open
    return File(open(self.path(name), mode))
IOError: [Errno 2] No such file or directory: u'<path_to_my_photo>'

Weirder, when I start at id=35000, then it crashes the same way, but, after having displayed 36668 ids...

photos = Photo.objects.filter(id__gte=35000)
for p in photos:
    print p.id

When I individually query the 36668th or the 36680th object, everything seems OK.

I can't understand why Django tries to get "get_image_dimensions" when I just read the photos list ?

Any idea ?

It would be helpful you post the Photo model. – jjimenez Sep 20 '13 at 07:11 — jjimenez, Sep 20 '13 at 07:11

score 0 · Answer 1 · answered Sep 19 '13 at 17:50

0

It seems like one of the Photo objects has an image field saved as '<path_to_my_photo>' which does not exist on disk.

answered Sep 19 '13 at 17:50

jproffitt

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42

In fact, none of the files exists on my dev server. But the error occurs only on certain files, and is not reproductible when I query these specific files. Too bad :( – user650108 Sep 19 '13 at 18:31
DO you have MEDIA_ROOT and MEDIA_URL set in your settings? – jproffitt Sep 19 '13 at 18:42
Yes I do. If I do p = Photo.objects.get(id=36605) and the print p.id, it works like a charm. – user650108 Sep 19 '13 at 18:53
So which Photo object is giving the error? What are the field values is has? There must be something different about that record. – jproffitt Sep 19 '13 at 19:18

Django weird behavior with model containing ImageField

1 Answers1