Allow relationships to be compared to scalars

flask_rest_jsonapi/data_layers/filtering/alchemy.py

@@ -3,6 +3,7 @@
 """Helper to create sqlalchemy filters according to filter querystring parameter"""
 
 from sqlalchemy import and_, or_, not_
+from sqlalchemy.orm import RelationshipProperty
 
 from flask_rest_jsonapi.exceptions import InvalidFilters
 from flask_rest_jsonapi.schema import get_relationships, get_model_field
@@ -51,6 +52,9 @@ def resolve(self):
 
             if isinstance(value, dict):
                 return getattr(self.column, self.operator)(**value)
+            elif isinstance(self.column.prop, RelationshipProperty) and isinstance(value, (int, str)):
+                relationship_key = next(iter(self.column.prop.local_columns))
+                return getattr(relationship_key, self.operator)(value)
             else:
                 return getattr(self.column, self.operator)(value)
 

flask_rest_jsonapi/resource.py

@@ -134,7 +134,7 @@ def get(self, *args, **kwargs):
         add_pagination_links(result,
                              objects_count,
                              qs,
-                             url_for(self.view, _external=True, **view_kwargs))
+                             url_for(request.endpoint, _external=True, **view_kwargs))
 
         result.update({'meta': {'count': objects_count}})
 

tests/test_sqlalchemy_data_layer.py

@@ -373,7 +373,7 @@ def get(self):
 
 
 @pytest.fixture(scope="module")
-def query():
+def query(computer_model, person_model):
     def query_(self, view_kwargs):
         if view_kwargs.get('person_id') is not None:
             return self.session.query(computer_model).join(person_model).filter_by(person_id=view_kwargs['person_id'])
@@ -641,6 +641,26 @@ def test_get_list_with_simple_filter(client, register_routes, person, person_2):
         response = client.get('/persons' + '?' + querystring, content_type='application/vnd.api+json')
         assert response.status_code == 200
 
+def test_get_list_relationship_filter(client, register_routes, person_computers,
+    computer_schema, person, person_2, computer, session):
+    """
+    Tests the ability to filter over a relationship using IDs, for example
+        `GET /comments?filter[post]=1`
+        Refer to the spec: https://jsonapi.org/recommendations/#filtering
+    """
+    # We have two people in the database, one of which owns a computer
+    person.computers.append(computer)
+    session.commit()
+
+    querystring = urlencode({
+        'filter[owner]': person.person_id
+    })
+    response = client.get('/computers?' + querystring, content_type='application/vnd.api+json')
+
+    # Check that the request worked, and returned the one computer we wanted
+    assert response.status_code == 200
+    assert len(response.json['data']) == 1
+
 def test_get_list_disable_pagination(client, register_routes):
     with client:
         querystring = urlencode({'page[size]': 0})
@@ -1804,3 +1824,4 @@ def test_api_resources(app, person_list):
 def test_relationship_containing_hyphens(client, register_routes, person_computers, computer_schema, person):
     response = client.get('/persons/{}/relationships/computers-owned'.format(person.person_id), content_type='application/vnd.api+json')
     assert response.status_code == 200
+