First stab at deleting file on update

thumbnails/fields.py

@@ -16,6 +16,7 @@ def __init__(self, *args, **kwargs):
         if kwargs.get('storage'):
             raise ValueError('Please define storage backend in settings.py instead on the field itself')
         kwargs['storage'] = storage.get_backend()
+        self.delete_on_update = kwargs.pop('delete_on_update', False)
         self.metadata_backend = metadata.get_backend()
         super(ImageField, self).__init__(*args, **kwargs)
 
@@ -28,7 +29,18 @@ def pre_save(self, model_instance, add):
         """
         file = getattr(model_instance, self.attname)
 
+        # new file is assigned
         if file and not file._committed:
+            # detect if there are old file needs to be cleaned
+            old_file = getattr(type(model_instance).objects.get(id=model_instance.id),
+                               self.attname)
+
+            if old_file:
+                all_thumbs = [thumb for thumb in old_file.thumbnails.all()]
+                for thumb_size in all_thumbs:
+                    old_file.thumbnails.delete(thumb_size)
+                old_file.delete()
+
             image_file = file
             if self.resize_source_to:
                 file.seek(0)

thumbnails/files.py

@@ -28,6 +28,9 @@ def save(self, name, content, save=True):
         self.metadata_backend.add_source(self.name)
         return thumbnail
 
+    def delete(self, save=True):
+        super(ThumbnailedImageFile, self).delete(save)
+
 
 class ThumbnailManager(object):
     """A class that manages creation and retrieval of thumbnails."""

thumbnails/tests/models.py

@@ -4,5 +4,5 @@
 
 
 class TestModel(models.Model):
-    avatar = ImageField(upload_to='avatars', resize_source_to='source')
+    avatar = ImageField(upload_to='avatars', resize_source_to='source', delete_on_update=True)
     profile_picture = ImageField(upload_to='avatars', blank=True, null=True, resize_source_to='source')

thumbnails/tests/test_fields.py

@@ -17,7 +17,10 @@ def setUp(self):
         with open('thumbnails/tests/tests.png', 'rb') as image_file:
             self.instance.avatar = File(image_file)
             self.instance.save()
+
         self.avatar_folder = \
+            os.path.join(self.instance.avatar.storage.temporary_location, 'avatars')
+        self.avatar_thumb_folder = \
             os.path.join(self.instance.avatar.storage.temporary_location, conf.BASE_DIR, 'avatars')
         self.basename = os.path.basename(self.instance.avatar.path)
         self.filename, self.ext = os.path.splitext(self.basename)
@@ -29,19 +32,19 @@ def tearDown(self):
     def test_image_field(self):
 
         # 1. Test for thumbnail creation
-        self.assertFalse(os.path.isfile(os.path.join(self.avatar_folder, self.filename + '_small' + self.ext)))
+        self.assertFalse(os.path.isfile(os.path.join(self.avatar_thumb_folder, self.filename + '_small' + self.ext)))
         thumb = self.instance.avatar.thumbnails.create(size='small')
-        self.assertTrue(os.path.isfile(os.path.join(self.avatar_folder, self.filename + '_small' + self.ext)))
+        self.assertTrue(os.path.isfile(os.path.join(self.avatar_thumb_folder, self.filename + '_small' + self.ext)))
 
         # Make sure the returned thumbnail is of thumbnail class, not metadata
         self.assertTrue(isinstance(thumb, Thumbnail))
         # 2. Test for getting thumbnail
         self.assertEqual(thumb, self.instance.avatar.thumbnails.get(size='small'))
 
         # 3. Test for thumbnail deletion
-        self.assertTrue(os.path.isfile(os.path.join(self.avatar_folder, self.filename + '_small' + self.ext)))
+        self.assertTrue(os.path.isfile(os.path.join(self.avatar_thumb_folder, self.filename + '_small' + self.ext)))
         self.instance.avatar.thumbnails.delete(size='small')
-        self.assertFalse(os.path.isfile(os.path.join(self.avatar_folder, self.filename + '_small' + self.ext)))
+        self.assertFalse(os.path.isfile(os.path.join(self.avatar_thumb_folder, self.filename + '_small' + self.ext)))
 
     def test_thumbnail_field(self):
         # Make sure ThumbnailManager return the correct thumbnail
@@ -58,7 +61,7 @@ def test_thumbnail_field(self):
 
         # Test for name clashing with another file with the same name
         self.instance.avatar.thumbnails.delete('large')
-        open(os.path.join(self.avatar_folder, 'tests_large.png'), 'w').close()
+        open(os.path.join(self.avatar_thumb_folder, 'tests_large.png'), 'w').close()
         self.instance.avatar.thumbnails.create('large')
 
         # Due to uuid4 for file name, this should not clash
@@ -142,3 +145,26 @@ def test_resize_source_to_none(self):
         with open('thumbnails/tests/tests.png', 'rb') as image_file:
             self.instance.profile_picture = File(image_file)
             self.instance.save()
+
+    def test_delete_on_update(self):
+        # create thumbnails + sanity check for file existence
+        self.instance.avatar.thumbnails.large
+        self.instance.avatar.thumbnails.small
+
+        original_file = os.path.join(self.avatar_folder, self.filename + self.ext)
+        small_thumb = os.path.join(self.avatar_thumb_folder, self.filename + '_small' + self.ext)
+        large_thumb = os.path.join(self.avatar_thumb_folder, self.filename + '_large' + self.ext)
+
+        self.assertTrue(os.path.isfile(original_file))
+        self.assertTrue(os.path.isfile(small_thumb))
+        self.assertTrue(os.path.isfile(large_thumb))
+
+        # if file is updated
+        with open('thumbnails/tests/tests.png', 'rb') as image_file:
+            self.instance.avatar = File(image_file)
+            self.instance.save()
+
+        # make sure all old files are deleted
+        self.assertFalse(os.path.isfile(original_file))
+        self.assertFalse(os.path.isfile(small_thumb))
+        self.assertFalse(os.path.isfile(large_thumb))