Handle partial processing results (#178)

* Handle missing data in backend (#135)

* Test missing data processing

server/server/model.py

@@ -18,6 +18,8 @@
 
 def prepare_serialization(data):
     """Perform a shallow serialization of field values if needed."""
+    if data is None:
+        return data
     for key, value in data.items():
         if type(value) in _SERIALIZE:
             serialize = _SERIALIZE[type(value)]
@@ -57,7 +59,7 @@ def file_dict(file, *, meta=False, signature=False, scenes=False, exif=False):
         }
         if meta:
             data["meta"] = Transform.metadata_dict(file.meta)
-        if signature:
+        if signature and file.signature is not None:
             data["signature"] = file.signature.signature
         if scenes:
             data["scenes"] = [Transform.scene_dict(scene, file=False) for scene in file.scenes]
@@ -69,6 +71,8 @@ def file_dict(file, *, meta=False, signature=False, scenes=False, exif=False):
     @serializable
     def metadata_dict(meta):
         """Get plain data representation for VideoMetadata."""
+        if meta is None:
+            return None
         fields = entity_fields(meta)
         fields -= {"id", "file_id", "file"}
         return {field: getattr(meta, field) for field in fields}
@@ -90,6 +94,8 @@ def scene_dict(scene, file=False):
     @serializable
     def exif_dict(exif):
         """Get plain data representation for Exif."""
+        if exif is None:
+            return None
         fields = entity_fields(exif)
         fields -= {"id", "file_id", "file", "Json_full_exif"}
         return {field: getattr(exif, field) for field in fields}

server/tests/server/test_model.py

@@ -64,3 +64,13 @@ def test_transform_file():
     data = Transform.file_dict(file, exif=True)
     assert data["file_path"] == file.file_path
     assert data["exif"]["General_FileSize"] == file.exif.General_FileSize
+
+
+def test_transform_partial():
+    file = Files(file_path="foo", sha256="bar", meta=None, exif=None, signature=None)
+
+    data = Transform.file_dict(file, meta=True, signature=True, exif=True)
+
+    assert data.get("meta") is None
+    assert data.get("exif") is None
+    assert data.get("signature") is None