Added get_proxy_object helper to filefields (#391)

docs/changelog.rst

@@ -4,6 +4,7 @@ Changelog
 
 Changes in 0.8.3
 ================
+- Added get_proxy_object helper to filefields (#391)
 - Added QuerySetNoCache and QuerySet.no_cache() for lower memory consumption (#365)
 - Fixed sum and average mapreduce dot notation support (#375, #376, #393)
 - Fixed as_pymongo to return the id (#386)

mongoengine/fields.py

@@ -1190,7 +1190,7 @@ class FileField(BaseField):
         # Check if a file already exists for this model
         grid_file = instance._data.get(self.name)
         if not isinstance(grid_file, self.proxy_class):
-            grid_file = self.get_proxy_obj(key=key, instance=instance)
+            grid_file = self.get_proxy_obj(key=self.name, instance=instance)
             instance._data[self.name] = grid_file
 
         if not grid_file.key:
@@ -1225,9 +1225,9 @@ class FileField(BaseField):
         if collection_name is None:
             collection_name = self.collection_name
 
-        return  self.proxy_class(key=key, instance=instance,
+        return self.proxy_class(key=key, instance=instance,
-                                 db_alias=db_alias,
+                                db_alias=db_alias,
-                                 collection_name=collection_name)
+                                collection_name=collection_name)
 
     def to_mongo(self, value):
         # Store the GridFS file id in MongoDB
@@ -1261,10 +1261,8 @@ class ImageGridFsProxy(GridFSProxy):
         applying field properties (size, thumbnail_size)
         """
         field = self.instance._fields[self.key]
-        # if the field from the instance has an attribute field
+        # Handle nested fields
-        # we use that one and hope for the best. Usually only container
+        if hasattr(field, 'field') and isinstance(field.field, FileField):
-        # fields have a field attribute.
-        if hasattr(field, 'field'):
             field = field.field
 
         try:

tests/fields/file_tests.py

@@ -455,5 +455,31 @@ class FileTest(unittest.TestCase):
         self.assertEqual(1, TestImage.objects(Q(image1=grid_id)
                                               or Q(image2=grid_id)).count())
 
+    def test_complex_field_filefield(self):
+        """Ensure you can add meta data to file"""
+
+        class Animal(Document):
+            genus = StringField()
+            family = StringField()
+            photos = ListField(FileField())
+
+        Animal.drop_collection()
+        marmot = Animal(genus='Marmota', family='Sciuridae')
+
+        marmot_photo = open(TEST_IMAGE_PATH, 'rb')  # Retrieve a photo from disk
+
+        photos_field = marmot._fields['photos'].field
+        new_proxy = photos_field.get_proxy_obj('photos', marmot)
+        new_proxy.put(marmot_photo, content_type='image/jpeg', foo='bar')
+        marmot_photo.close()
+
+        marmot.photos.append(new_proxy)
+        marmot.save()
+
+        marmot = Animal.objects.get()
+        self.assertEqual(marmot.photos[0].content_type, 'image/jpeg')
+        self.assertEqual(marmot.photos[0].foo, 'bar')
+        self.assertEqual(marmot.photos[0].get().length, 8313)
+
 if __name__ == '__main__':
     unittest.main()