Add default limit and max limit config vars

docs/rest-api.yml

@@ -108,7 +108,7 @@ paths:
           description: |
             Return a finite number of users.
             Can be used with offset to paginate.
-            If unspecified, return all users.
+            If unspecified, use api_page_default_limit.
       responses:
         "200":
           description: The Hub's user list
@@ -455,7 +455,7 @@ paths:
           description: |
             Return a finite number of groups.
             Can be used with offset to paginate.
-            If unspecified, return all groups.
+            If unspecified, use api_page_default_limit.
       responses:
         "200":
           description: The list of groups
@@ -487,7 +487,7 @@ paths:
           description: |
             Return a finite number of users within the given group.
             Can be used with offset to paginate.
-            If unspecified, return all users.
+            If unspecified, use api_page_default_limit
       responses:
         "200":
           description: The group model
@@ -610,7 +610,7 @@ paths:
           description: |
             Return a finite number of routes.
             Can be used with offset to paginate.
-            If unspecified, return all routes.
+            If unspecified, use api_page_default_limit
       responses:
         "200":
           description: Routing table

docs/source/reference/rest.md

@@ -175,6 +175,8 @@ r.raise_for_status()
 r.json()
 ```
 
+By default, pagination limit will be specified by the `JupyterHub.api_page_default_limit` config variable.
+
 Pagination is enabled on the `GET /users`, `GET /groups`, `GET /groups/{name}`, and `GET /proxy` REST endpoints.
 
 ## Enabling users to spawn multiple named-servers via the API

jupyterhub/apihandlers/groups.py

@@ -39,7 +39,8 @@ class GroupListAPIHandler(_GroupAPIHandler):
     def get(self):
         """List groups"""
         offset = self.get_argument("offset", None)
-        limit = self.get_argument("limit", None)
+        limit = self.get_argument("limit", self.settings['app'].api_page_default_limit)
+        max_limit = self.settings['app'].api_page_max_limit
 
         query = self.db.query(orm.Group)
 
@@ -52,14 +53,18 @@ class GroupListAPIHandler(_GroupAPIHandler):
                 )
             query = query.offset(offset)
 
-        if limit is not None:
+        if limit != self.settings['app'].api_page_default_limit:
             try:
                 limit = int(limit)
+                if limit > max_limit:
+                    limit = max_limit
+
             except Exception as e:
                 raise web.HTTPError(
                     400, "Invalid argument type, limit must be an integer"
                 )
-            query = query.limit(int(limit))
+
+        query = query.limit(limit)
 
         data = [self.group_model(group) for group in query]
         self.write(json.dumps(data))
@@ -100,13 +105,12 @@ class GroupAPIHandler(_GroupAPIHandler):
     @admin_only
     def get(self, name):
         offset = self.get_argument("offset", None)
-        limit = self.get_argument("limit", None)
+        limit = self.get_argument("limit", self.settings['app'].api_page_default_limit)
+        max_limit = self.settings['app'].api_page_max_limit
+
         group = self.find_group(name)
         users_slice = None
 
-        print(type(group.users))
-        print(group.users)
-
         if offset is not None:
             try:
                 offset = int(offset)
@@ -117,9 +121,11 @@ class GroupAPIHandler(_GroupAPIHandler):
 
             group.users = group.users[offset:]
 
-        if limit is not None:
+        if limit != self.settings['app'].api_page_default_limit:
             try:
                 limit = int(limit)
+                if limit > max_limit:
+                    limit = max_limit
             except Exception as e:
                 raise web.HTTPError(
                     400, "Invalid argument type, limit must be an integer"

jupyterhub/apihandlers/proxy.py

@@ -18,7 +18,8 @@ class ProxyAPIHandler(APIHandler):
         but without clients needing to maintain separate
         """
         offset = self.get_argument("offset", None)
-        limit = self.get_argument("limit", None)
+        limit = self.get_argument("limit", self.settings['app'].api_page_default_limit)
+        max_limit = self.settings['app'].api_page_max_limit
 
         routes = await self.proxy.get_all_routes()
 
@@ -35,9 +36,11 @@ class ProxyAPIHandler(APIHandler):
                 if key in routes
             }
 
-        if limit is not None:
+        if limit != self.settings['app'].api_page_default_limit:
             try:
                 limit = int(limit)
+                if limit > max_limit:
+                    limit = max_limit
             except Exception as e:
                 raise web.HTTPError(
                     400, "Invalid argument type, limit must be an integer"

jupyterhub/apihandlers/users.py

@@ -56,7 +56,8 @@ class UserListAPIHandler(APIHandler):
     def get(self):
         state_filter = self.get_argument("state", None)
         offset = self.get_argument("offset", None)
-        limit = self.get_argument("limit", None)
+        limit = self.get_argument("limit", self.settings['app'].api_page_default_limit)
+        max_limit = self.settings['app'].api_page_max_limit
 
         # post_filter
         post_filter = None
@@ -99,10 +100,25 @@ class UserListAPIHandler(APIHandler):
 
         # Apply offset and limit for request pagination
         if offset is not None:
-            query = query.offset(int(offset))
+            try:
+                offset = int(offset)
+            except Exception as e:
+                raise web.HTTPError(
+                    400, "Invalid argument type, offset must be an integer"
+                )
+            query = query.offset(offset)
 
-        if limit is not None:
+        if limit != self.settings['app'].api_page_default_limit:
-            query = query.limit(int(limit))
+            try:
+                limit = int(limit)
+                if limit > max_limit:
+                    limit = max_limit
+            except Exception as e:
+                raise web.HTTPError(
+                    400, "Invalid argument type, limit must be an integer"
+                )
+
+        query = query.limit(limit)
 
         data = [
             self.user_model(u, include_servers=True, include_state=True)

jupyterhub/app.py

@@ -936,6 +936,15 @@ class JupyterHub(Application):
         """,
     ).tag(config=True)
 
+    api_page_default_limit = Integer(
+        50,
+        help="The default amount of records returned by a paginated endpoint",
+    ).tag(config=True)
+
+    api_page_max_limit = Integer(
+        200, help="The maximum amount of records that can be returned at once"
+    )
+
     authenticate_prometheus = Bool(
         True, help="Authentication for prometheus metrics"
     ).tag(config=True)