Added descendant_of support

wagtail/contrib/wagtailapi/endpoints.py

@@ -316,6 +316,7 @@ class PagesAPIEndpoint(BaseAPIEndpoint):
     known_query_parameters = BaseAPIEndpoint.known_query_parameters.union([
         'type',
         'child_of',
+        'descendant_of',
     ])
 
     def get_queryset(self, request, model=Page):
@@ -386,12 +387,32 @@ class PagesAPIEndpoint(BaseAPIEndpoint):
 
             try:
                 parent_page = self.get_queryset(request).get(id=parent_page_id)
-                return queryset.child_of(parent_page)
+                queryset = queryset.child_of(parent_page)
+                queryset._filtered_by_child_of = True
+                return queryset
             except Page.DoesNotExist:
                 raise BadRequestError("parent page doesn't exist")
 
         return queryset
 
+    def do_descendant_of_filter(self, request, queryset):
+        if 'descendant_of' in request.GET:
+            if getattr(queryset, '_filtered_by_child_of', False):
+                raise BadRequestError("filtering by descendant_of with child_of is not supported")
+            try:
+                ancestor_page_id = int(request.GET['descendant_of'])
+                assert ancestor_page_id >= 0
+            except (ValueError, AssertionError):
+                raise BadRequestError("descendant_of must be a positive integer")
+
+            try:
+                ancestor_page = self.get_queryset(request).get(id=ancestor_page_id)
+                return queryset.descendant_of(ancestor_page)
+            except Page.DoesNotExist:
+                raise BadRequestError("ancestor page doesn't exist")
+
+        return queryset
+
     def listing_view(self, request):
         # Get model and queryset
         model = self.get_model(request)
@@ -403,6 +424,7 @@ class PagesAPIEndpoint(BaseAPIEndpoint):
         # Filtering
         queryset = self.do_field_filtering(request, queryset)
         queryset = self.do_child_of_filter(request, queryset)
+        queryset = self.do_descendant_of_filter(request, queryset)
 
         # Ordering
         queryset = self.do_ordering(request, queryset)

wagtail/contrib/wagtailapi/tests/test_pages.py

@@ -292,6 +292,52 @@ class TestPageListing(TestCase):
         self.assertEqual(content, {'message': "parent page doesn't exist"})
 
 
+    # DESCENDANT OF FILTER
+
+    def test_descendant_of_filter(self):
+        response = self.get_response(descendant_of=6)
+        content = json.loads(response.content.decode('UTF-8'))
+
+        page_id_list = self.get_page_id_list(content)
+        self.assertEqual(page_id_list, [10, 15, 17, 21, 22, 23])
+
+    def test_descendant_of_with_type(self):
+        response = self.get_response(type='tests.EventPage', descendant_of=6)
+        content = json.loads(response.content.decode('UTF-8'))
+
+        page_id_list = self.get_page_id_list(content)
+        self.assertEqual(page_id_list, [])
+
+    def test_descendant_of_unknown_page_gives_error(self):
+        response = self.get_response(descendant_of=1000)
+        content = json.loads(response.content.decode('UTF-8'))
+
+        self.assertEqual(response.status_code, 400)
+        self.assertEqual(content, {'message': "ancestor page doesn't exist"})
+
+    def test_descendant_of_not_integer_gives_error(self):
+        response = self.get_response(descendant_of='abc')
+        content = json.loads(response.content.decode('UTF-8'))
+
+        self.assertEqual(response.status_code, 400)
+        self.assertEqual(content, {'message': "descendant_of must be a positive integer"})
+
+    def test_descendant_of_page_thats_not_in_same_site_gives_error(self):
+        # Root page is not in any site, so pretend it doesn't exist
+        response = self.get_response(descendant_of=1)
+        content = json.loads(response.content.decode('UTF-8'))
+
+        self.assertEqual(response.status_code, 400)
+        self.assertEqual(content, {'message': "ancestor page doesn't exist"})
+
+    def test_descendant_of_when_filtering_by_child_of_gives_error(self):
+        response = self.get_response(descendant_of=6, child_of=5)
+        content = json.loads(response.content.decode('UTF-8'))
+
+        self.assertEqual(response.status_code, 400)
+        self.assertEqual(content, {'message': "filtering by descendant_of with child_of is not supported"})
+
+
     # ORDERING
 
     def test_ordering_default(self):