Implement special "root" page value for child_of/decendant_of filters

This adds the ability to specify "root" to the child_of and decendant_of filters, which represents the homepage of the current site.

wagtail/api/v2/filters.py

@@ -114,6 +114,9 @@ class ChildOfFilter(BaseFilterBackend):
     Implements the ?child_of filter used to filter the results to only contain
     pages that are direct children of the specified page.
     """
+    def get_root_page(self, request):
+        return Page.get_first_root_node()
+
     def get_page_by_id(self, request, page_id):
         return Page.objects.get(id=page_id)
 
@@ -125,7 +128,10 @@ class ChildOfFilter(BaseFilterBackend):
 
                 parent_page = self.get_page_by_id(request, parent_page_id)
             except (ValueError, AssertionError):
-                raise BadRequestError("child_of must be a positive integer")
+                if request.GET['child_of'] == 'root':
+                    parent_page = self.get_root_page(request)
+                else:
+                    raise BadRequestError("child_of must be a positive integer")
             except Page.DoesNotExist:
                 raise BadRequestError("parent page doesn't exist")
 
@@ -140,6 +146,9 @@ class RestrictedChildOfFilter(ChildOfFilter):
     A restricted version of ChildOfFilter that only allows pages in the current
     site to be specified.
     """
+    def get_root_page(self, request):
+        return request.site.root_page
+
     def get_page_by_id(self, request, page_id):
         site_pages = pages_for_site(request.site)
         return site_pages.get(id=page_id)
@@ -150,6 +159,9 @@ class DescendantOfFilter(BaseFilterBackend):
     Implements the ?decendant_of filter which limits the set of pages to a
     particular branch of the page tree.
     """
+    def get_root_page(self, request):
+        return Page.get_first_root_node()
+
     def get_page_by_id(self, request, page_id):
         return Page.objects.get(id=page_id)
 
@@ -163,7 +175,10 @@ class DescendantOfFilter(BaseFilterBackend):
 
                 parent_page = self.get_page_by_id(request, parent_page_id)
             except (ValueError, AssertionError):
-                raise BadRequestError("descendant_of must be a positive integer")
+                if request.GET['descendant_of'] == 'root':
+                    parent_page = self.get_root_page(request)
+                else:
+                    raise BadRequestError("descendant_of must be a positive integer")
             except Page.DoesNotExist:
                 raise BadRequestError("ancestor page doesn't exist")
 
@@ -177,6 +192,9 @@ class RestrictedDescendantOfFilter(DescendantOfFilter):
     A restricted version of DecendantOfFilter that only allows pages in the current
     site to be specified.
     """
+    def get_root_page(self, request):
+        return request.site.root_page
+
     def get_page_by_id(self, request, page_id):
         site_pages = pages_for_site(request.site)
         return site_pages.get(id=page_id)

wagtail/api/v2/tests/test_pages.py

@@ -286,6 +286,14 @@ class TestPageListing(TestCase):
         page_id_list = self.get_page_id_list(content)
         self.assertEqual(page_id_list, [16, 18, 19])
 
+    def test_child_of_root(self):
+        # "root" gets children of the homepage of the current site
+        response = self.get_response(child_of='root')
+        content = json.loads(response.content.decode('UTF-8'))
+
+        page_id_list = self.get_page_id_list(content)
+        self.assertEqual(page_id_list, [4, 5, 6, 20, 12])
+
     def test_child_of_with_type(self):
         response = self.get_response(type='demosite.EventPage', child_of=5)
         content = json.loads(response.content.decode('UTF-8'))
@@ -325,6 +333,15 @@ class TestPageListing(TestCase):
         page_id_list = self.get_page_id_list(content)
         self.assertEqual(page_id_list, [10, 15, 17, 21, 22, 23])
 
+    def test_descendant_of_root(self):
+        # "root" gets decendants of the homepage of the current site
+        # Basically returns every page except the homepage
+        response = self.get_response(descendant_of='root')
+        content = json.loads(response.content.decode('UTF-8'))
+
+        page_id_list = self.get_page_id_list(content)
+        self.assertEqual(page_id_list, [4, 8, 9, 5, 16, 18, 19, 6, 10, 15, 17, 21, 22, 23, 20, 13, 14, 12])
+
     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'))