Merge pull request #469 from matthewwithanm/fix-image-cachefile-serializtion

Fix pickle serialization for ImageCacheFile

docs/caching.rst

@@ -185,6 +185,11 @@ Or, in Python:
             def on_source_saved(self, file):
                 file.generate()
 
+.. note::
+
+    If you use custom storage backend for some specs,
+    (storage passed to the field different than configured one)
+    it's required the storage to be pickleable
 
 
 __ https://pypi.python.org/pypi/django-celery

imagekit/cachefiles/__init__.py

@@ -144,8 +144,24 @@ class ImageCacheFile(BaseIKFile, ImageFile):
         # file is hidden link to "file" attribute
         state.pop('_file', None)
 
+        # remove storage from state as some non-FileSystemStorage can't be
+        # pickled
+        settings_storage = get_singleton(
+            settings.IMAGEKIT_DEFAULT_FILE_STORAGE,
+            'file storage backend'
+        )
+        if state['storage'] == settings_storage:
+            state.pop('storage')
         return state
 
+    def __setstate__(self, state):
+        if 'storage' not in state:
+            state['storage'] = get_singleton(
+                settings.IMAGEKIT_DEFAULT_FILE_STORAGE,
+                'file storage backend'
+            )
+        self.__dict__.update(state)
+
     def __nonzero__(self):
         # Python 2 compatibility
         return self.__bool__()

tests/test_serialization.py

@@ -37,4 +37,7 @@ def test_cachefiles():
     # remove link to file from spec source generator
     # test __getstate__ of ImageCacheFile
     file.generator.source = None
-    pickleback(file)
+    restored_file = pickleback(file)
+    assert file is not restored_file
+    # Assertion for #437 and #451
+    assert file.storage is restored_file.storage