Cleanup referenced GridFS files when a document is deleted

mongoengine/base.py

@@ -616,6 +616,10 @@ def _get_mixin_fields(base):
                     raise InvalidDocumentError("Reverse delete rules are not supported for EmbeddedDocuments (field: %s)" % field.name)
                 f.document_type.register_delete_rule(new_class, field.name, delete_rule)
 
+            proxy_class = getattr(field, 'proxy_class', None)
+            if proxy_class is not None:
+                new_class.register_proxy_field(field.name, proxy_class)
+
             if field.name and hasattr(Document, field.name) and EmbeddedDocument not in new_class.mro():
                 raise InvalidDocumentError("%s is a document method and not a valid field name" % field.name)
 
@@ -717,6 +721,7 @@ def __new__(cls, name, bases, attrs):
             'index_opts': {},
             'queryset_class': QuerySet,
             'delete_rules': {},
+            'proxy_fields': {},
             'allow_inheritance': True
         }
 

mongoengine/document.py

@@ -277,6 +277,11 @@ def delete(self, safe=False):
         signals.pre_delete.send(self.__class__, document=self)
 
         try:
+            for field_name in self._meta['proxy_fields']:
+                proxy_class = self._meta['proxy_fields'][field_name]
+                if hasattr(proxy_class, 'delete'):
+                    proxy = getattr(self, field_name)
+                    proxy.delete()
             self.__class__.objects(pk=self.pk).delete(safe=safe)
         except pymongo.errors.OperationFailure, err:
             message = u'Could not delete document (%s)' % err.message
@@ -341,6 +346,13 @@ def register_delete_rule(cls, document_cls, field_name, rule):
         """
         cls._meta['delete_rules'][(document_cls, field_name)] = rule
 
+    @classmethod
+    def register_proxy_field(cls, field_name, proxy_class):
+        """This method registers fields with proxy classes to delete them when
+        removing this object.
+        """
+        cls._meta['proxy_fields'][field_name] = proxy_class
+
     @classmethod
     def drop_collection(cls):
         """Drops the entire collection associated with this

tests/fields.py

@@ -1546,6 +1546,39 @@ class DemoFile(Document):
             file = FileField()
         DemoFile.objects.create()
 
+    def test_file_delete_cleanup(self):
+        """Ensure that the gridfs file is deleted when a document
+        with a GridFSProxied Field is deleted"""
+        class TestFile(Document):
+            file = FileField()
+
+        class TestImage(Document):
+            image = ImageField()
+
+        TestFile.drop_collection()
+
+        testfile = TestFile()
+        testfile.file.put('Hello, World!')
+        testfile.save()
+
+        testfile_grid_id = testfile.file.grid_id
+        testfile_fs = testfile.file.fs
+
+        testfile.delete()
+        self.assertFalse(testfile_fs.exists(testfile_grid_id))
+
+        TestImage.drop_collection()
+
+        testimage = TestImage()
+        testimage.image.put(open(TEST_IMAGE_PATH, 'r'))
+        testimage.save()
+
+        testimage_grid_id = testimage.image.grid_id
+        testimage_fs = testimage.image.fs
+
+        testimage.delete()
+        self.assertFalse(testimage_fs.exists(testimage_grid_id))
+
     def test_file_uniqueness(self):
         """Ensure that each instance of a FileField is unique
         """