Restructure SchemaGenerator for easier subclassing

Allow adding new default list actions so that bulk actions can be
included in the schema with minimal changes.

rest_framework/schemas.py

@@ -124,28 +124,6 @@ def insert_into(target, keys, value):
     target[keys[-1]] = value
 
 
-def is_custom_action(action):
-    return action not in set([
-        'retrieve', 'list', 'create', 'update', 'partial_update', 'destroy'
-    ])
-
-
-def is_list_view(path, method, view):
-    """
-    Return True if the given path/method appears to represent a list view.
-    """
-    if hasattr(view, 'action'):
-        # Viewsets have an explicitly defined action, which we can inspect.
-        return view.action == 'list'
-
-    if method.lower() != 'get':
-        return False
-    path_components = path.strip('/').split('/')
-    if path_components and '{' in path_components[-1]:
-        return False
-    return True
-
-
 def endpoint_ordering(endpoint):
     path, method, callback = endpoint
     method_priority = {
@@ -265,6 +243,9 @@ class SchemaGenerator(object):
         'patch': 'partial_update',
         'delete': 'destroy',
     }
+    default_list_mapping = {
+        'get': 'list',
+    }
     endpoint_inspector_cls = EndpointInspector
 
     # Map the method names we use for viewset actions onto external schema names.
@@ -293,6 +274,10 @@ class SchemaGenerator(object):
         self.description = description
         self.url = url
         self.endpoints = None
+        self.default_actions = set(
+            list(self.default_mapping.values()) +
+            list(self.default_list_mapping.values())
+        )
 
     def get_schema(self, request=None, public=False):
         """
@@ -602,7 +587,9 @@ class SchemaGenerator(object):
         return fields
 
     def get_pagination_fields(self, path, method, view):
-        if not is_list_view(path, method, view):
+        if not self.is_list_view(path, method, view):
+            return []
+        if method.lower() != 'get':
             return []
 
         pagination = getattr(view, 'pagination_class', None)
@@ -613,7 +600,7 @@ class SchemaGenerator(object):
         return paginator.get_schema_fields(view)
 
     def get_filter_fields(self, path, method, view):
-        if not is_list_view(path, method, view):
+        if not self.is_list_view(path, method, view):
             return []
 
         if not getattr(view, 'filter_backends', None):
@@ -643,8 +630,8 @@ class SchemaGenerator(object):
             action = view.action
         else:
             # Views have no associated action, so we determine one from the method.
-            if is_list_view(subpath, method, view):
-                action = 'list'
+            if self.is_list_view(subpath, method, view):
+                action = self.default_list_mapping[method.lower()]
             else:
                 action = self.default_mapping[method.lower()]
 
@@ -654,7 +641,7 @@ class SchemaGenerator(object):
             if '{' not in component
         ]
 
-        if is_custom_action(action):
+        if self.is_custom_action(action):
             # Custom action, eg "/users/{pk}/activate/", "/users/active/"
             if len(view.action_map) > 1:
                 action = self.default_mapping[method.lower()]
@@ -670,6 +657,24 @@ class SchemaGenerator(object):
         # Default action, eg "/users/", "/users/{pk}/"
         return named_path_components + [action]
 
+    def is_custom_action(self, action):
+        return action not in self.default_actions
+
+    def is_list_view(self, path, method, view):
+        """
+        Return True if the given path/method appears to represent a list view.
+        """
+        if hasattr(view, 'action'):
+            # Viewsets have an explicitly defined action, which we can inspect.
+            return view.action in self.default_list_mapping.values()
+
+        if method.lower() not in self.default_list_mapping:
+            return False
+        path_components = path.strip('/').split('/')
+        if path_components and '{' in path_components[-1]:
+            return False
+        return True
+
 
 class SchemaView(APIView):
     _ignore_model_permissions = True