diff --git a/jupyterhub/handlers/base.py b/jupyterhub/handlers/base.py
index 8e508fce..6f40d6c9 100644
--- a/jupyterhub/handlers/base.py
+++ b/jupyterhub/handlers/base.py
@@ -602,7 +602,7 @@ class BaseHandler(RequestHandler):
 
         self.log.debug("Initiating spawn for %s", user_server_name)
 
-        spawn_future = user.spawn(server_name, options)
+        spawn_future = user.spawn(server_name, options, handler=self)
 
         self.log.debug("%i%s concurrent spawns",
             spawn_pending_count,
diff --git a/jupyterhub/spawner.py b/jupyterhub/spawner.py
index ff76b66c..c0a7d3a7 100644
--- a/jupyterhub/spawner.py
+++ b/jupyterhub/spawner.py
@@ -161,6 +161,7 @@ class Spawner(LoggingConfigurable):
     admin_access = Bool(False)
     api_token = Unicode()
     oauth_client_id = Unicode()
+    handler = Any()
 
     will_resume = Bool(False,
         help="""Whether the Spawner will resume on next start
diff --git a/jupyterhub/user.py b/jupyterhub/user.py
index f65affc4..95cbb5f8 100644
--- a/jupyterhub/user.py
+++ b/jupyterhub/user.py
@@ -331,7 +331,7 @@ class User:
             url_parts.extend(['server/progress'])
         return url_path_join(*url_parts)
 
-    async def spawn(self, server_name='', options=None):
+    async def spawn(self, server_name='', options=None, handler=None):
         """Start the user's spawner
 
         depending from the value of JupyterHub.allow_named_servers
@@ -361,6 +361,9 @@ class User:
         spawner.server = server = Server(orm_server=orm_server)
         assert spawner.orm_spawner.server is orm_server
 
+        # pass requesting handler to the spawner
+        # e.g. for processing GET params
+        spawner.handler = handler
         # Passing user_options to the spawner
         spawner.user_options = options or {}
         # we are starting a new server, make sure it doesn't restore state
@@ -484,6 +487,9 @@ class User:
             # raise original exception
             spawner._start_pending = False
             raise e
+        finally:
+            # clear reference to handler after start finishes
+            spawner.handler = None
         spawner.start_polling()
 
         # store state