Added GenericRelationFilter

api/funkwhale_api/common/fields.py

@@ -57,6 +57,64 @@ class SmartSearchFilter(django_filters.CharFilter):
         return search.apply(qs, cleaned)
 
 
+def get_generic_filter_query(value, relation_name, choices):
+    parts = value.split(":", 1)
+    type = parts[0]
+    try:
+        conf = choices[type]
+    except KeyError:
+        raise forms.ValidationError("Invalid type")
+    related_queryset = conf["queryset"]
+    related_model = related_queryset.model
+    filter_query = models.Q(
+        **{
+            "{}_content_type__app_label".format(
+                relation_name
+            ): related_model._meta.app_label,
+            "{}_content_type__model".format(
+                relation_name
+            ): related_model._meta.model_name,
+        }
+    )
+    if len(parts) > 1:
+        id_attr = conf.get("id_attr", "id")
+        id_field = conf.get("id_field", serializers.IntegerField(min_value=1))
+        try:
+            id_value = parts[1]
+            id_value = id_field.to_internal_value(id_value)
+        except (TypeError, KeyError, serializers.ValidationError):
+            raise forms.ValidationError("Invalid id")
+        query_getter = conf.get(
+            "get_query", lambda attr, value: models.Q(**{attr: value})
+        )
+        obj_query = query_getter(id_attr, id_value)
+        try:
+            obj = related_queryset.get(obj_query)
+        except related_queryset.model.DoesNotExist:
+            raise forms.ValidationError("Invalid object")
+        filter_query &= models.Q(**{"{}_id".format(relation_name): obj.id})
+
+    return filter_query
+
+
+class GenericRelationFilter(django_filters.CharFilter):
+    def __init__(self, relation_name, choices, *args, **kwargs):
+        self.relation_name = relation_name
+        self.choices = choices
+        super().__init__(*args, **kwargs)
+
+    def filter(self, qs, value):
+        if not value:
+            return qs
+        try:
+            filter_query = get_generic_filter_query(
+                value, relation_name=self.relation_name, choices=self.choices
+            )
+        except forms.ValidationError:
+            return qs.none()
+        return qs.filter(filter_query)
+
+
 class GenericRelation(serializers.JSONField):
     def __init__(self, choices, *args, **kwargs):
         self.choices = choices