Merge pull request #34 from ajite/feat-nested-sort

feat: sorting works with nested attributes

CHANGES

@@ -9,6 +9,9 @@ Upcoming version:
 - Fix for an incorrect error message
 - Returns 500 instead 400 response code in case of serialization errors in POST requests
 
+Version 2.3.0
+------------
+- Allow sorting of nested fields
 
 Version 2.2.9
 -------------

flask_restless/__init__.py

@@ -13,7 +13,7 @@
 
 """
 #: The current version of this extension.
-__version__ = '2.2.9'
+__version__ = '2.3.0'
 
 
 # The following names are available as part of the public API for Flask-Restless-NG.

flask_restless/search.py

@@ -416,17 +416,16 @@ def get_field(obj, name):
     if sort:
         for (symbol, field_name) in sort:
             direction_name = 'asc' if symbol == '+' else 'desc'
-            if '.' in field_name:
-                field_name, field_name_in_relation = field_name.split('.')
-                relation_model = aliased(get_related_model(model, field_name))
-                field = get_field(relation_model, field_name_in_relation)
-                direction = getattr(field, direction_name)
-                query = query.join(relation_model)
-                query = query.order_by(direction())
-            else:
-                field = get_field(model, field_name)
-                direction = getattr(field, direction_name)
-                query = query.order_by(direction())
+            related_model = model
+            while '.' in field_name:
+                field_name, _, field_name_in_relation = field_name.partition('.')
+                related_model = aliased(get_related_model(related_model, field_name))
+                field_name = field_name_in_relation
+                query = query.join(related_model)
+
+            field = get_field(related_model, field_name)
+            direction = getattr(field, direction_name)
+            query = query.order_by(direction())
     else:
         pks = primary_key_names(model)
         pk_order = (getattr(model, field).asc() for field in pks)

tests/test_jsonapi/test_sorting.py

@@ -6,6 +6,7 @@
 from ..conftest import BaseTestClass
 from .models import Article
 from .models import Base
+from .models import Comment
 from .models import Person
 
 
@@ -22,6 +23,7 @@ def setup(self):
         manager = APIManager(self.app, session=self.session)
         manager.create_api(Article)
         manager.create_api(Person)
+        manager.create_api(Comment)
         Base.metadata.create_all(bind=self.engine)
         yield
         Base.metadata.drop_all(bind=self.engine)
@@ -165,3 +167,66 @@ def test_bad_request_on_incorrect_sorting_field(self):
     def test_bad_request_on_incorrect_sorting_relationship_field(self):
         query_string = {'sort': 'articles.unknown'}
         self.fetch_and_validate('/api/person', query_string=query_string, expected_response_code=400, error_msg='No such field unknown')
+
+    def test_sort_nested_relationship_attributes(self):
+        """Tests that the client can sort by nested relationship attributes.
+
+        For more information, see the `Sorting`_ section of the JSON API
+        specification.
+
+        .. _Sorting: https://jsonapi.org/format/#fetching-sorting
+
+        """
+        self.session.add_all([
+            Person(pk=1, age=20),
+            Person(pk=2, age=10),
+            Person(pk=3, age=30),
+            Article(id=1, author_id=1),
+            Article(id=2, author_id=2),
+            Article(id=3, author_id=3),
+            Comment(id=1, author_id=1, article_id=1),
+            Comment(id=2, author_id=1, article_id=2),
+            Comment(id=3, author_id=1, article_id=3),
+            Comment(id=4, author_id=2, article_id=1),
+            Comment(id=5, author_id=2, article_id=2),
+            Comment(id=6, author_id=3, article_id=1)
+        ])
+        self.session.commit()
+        query_string = {'sort': 'article.author.age'}
+        document = self.fetch_and_validate('/api/comment', query_string=query_string)
+        comments = document['data']
+        assert ['2', '5', '1', '4', '6', '3'] == [comment['id'] for comment in comments]
+
+    def test_sort_multiple_nested_relationship_attributes(self):
+        """Tests that the client can sort by multiple nested relationship
+        attributes.
+
+        For more information, see the `Sorting`_ section of the JSON API
+        specification.
+
+        .. _Sorting: https://jsonapi.org/format/#fetching-sorting
+
+        """
+        self.session.bulk_save_objects([
+            Person(pk=1, age=2, name=u'b'),
+            Person(pk=2, age=1, name=u'd'),
+            Person(pk=3, age=1, name=u'a'),
+            Article(id=1, author_id=1),
+            Article(id=2, author_id=2),
+            Article(id=3, author_id=3),
+            Comment(id=1, author_id=1, article_id=1),
+            Comment(id=2, author_id=1, article_id=2),
+            Comment(id=3, author_id=1, article_id=3),
+            Comment(id=4, author_id=2, article_id=1),
+            Comment(id=5, author_id=2, article_id=2),
+            Comment(id=6, author_id=3, article_id=1)
+        ])
+        self.session.commit()
+        query_string = {'sort': 'article.author.age,article.author.name'}
+        document = self.fetch_and_validate('/api/comment', query_string=query_string)
+        comments = document['data']
+        assert ['3', '2', '5', '1', '4', '6'] == [comment['id'] for comment in comments]
+
+    def test_bad_request_on_incorrect_sorting_nested_relationship_field(self):
+        query_string = {'sort': 'article.author.unknown'}
+        self.fetch_and_validate('/api/comment', query_string=query_string, expected_response_code=400, error_msg='No such field unknown')