Refactor UI auth implementation

Instead of returning False when auth is incomplete, throw an exception which
can be caught with a wrapper.

1 files changed, 29 insertions, 17 deletions

diff --git a/synapse/handlers/auth.py b/synapse/handlers/auth.py
index 2f30f183ce..28c80608a7 100644
--- a/synapse/handlers/auth.py
+++ b/synapse/handlers/auth.py
@@ -17,7 +17,10 @@ from twisted.internet import defer
 
 from ._base import BaseHandler
 from synapse.api.constants import LoginType
-from synapse.api.errors import AuthError, LoginError, Codes, StoreError, SynapseError
+from synapse.api.errors import (
+    AuthError, Codes, InteractiveAuthIncompleteError, LoginError, StoreError,
+    SynapseError,
+)
 from synapse.module_api import ModuleApi
 from synapse.types import UserID
 from synapse.util.async import run_on_reactor
@@ -95,26 +98,36 @@ class AuthHandler(BaseHandler):
         session with a map, which maps each auth-type (str) to the relevant
         identity authenticated by that auth-type (mostly str, but for captcha, bool).
 
+        If no auth flows have been completed successfully, raises an
+        InteractiveAuthIncompleteError. To handle this, you can use
+        synapse.rest.client.v2_alpha._base.interactive_auth_handler as a
+        decorator.
+
         Args:
             flows (list): A list of login flows. Each flow is an ordered list of
                           strings representing auth-types. At least one full
                           flow must be completed in order for auth to be successful.
+
             clientdict: The dictionary from the client root level, not the
                         'auth' key: this method prompts for auth if none is sent.
+
             clientip (str): The IP address of the client.
+
         Returns:
-            A tuple of (authed, dict, dict, session_id) where authed is true if
-            the client has successfully completed an auth flow. If it is true
-            the first dict contains the authenticated credentials of each stage.
+            defer.Deferred[dict, dict, str]: a deferred tuple of
+                (creds, params, session_id).
 
-            If authed is false, the first dictionary is the server response to
-            the login request and should be passed back to the client.
+                'creds' contains the authenticated credentials of each stage.
 
-            In either case, the second dict contains the parameters for this
-            request (which may have been given only in a previous call).
+                'params' contains the parameters for this request (which may
+                have been given only in a previous call).
 
-            session_id is the ID of this session, either passed in by the client
-            or assigned by the call to check_auth
+                'session_id' is the ID of this session, either passed in by the
+                client or assigned by this call
+
+        Raises:
+            InteractiveAuthIncompleteError if the client has not yet completed
+                all the stages in any of the permitted flows.
         """
 
         authdict = None
@@ -142,11 +155,8 @@ class AuthHandler(BaseHandler):
             clientdict = session['clientdict']
 
         if not authdict:
-            defer.returnValue(
-                (
-                    False, self._auth_dict_for_flows(flows, session),
-                    clientdict, session['id']
-                )
+            raise InteractiveAuthIncompleteError(
+                self._auth_dict_for_flows(flows, session),
             )
 
         if 'creds' not in session:
@@ -190,12 +200,14 @@ class AuthHandler(BaseHandler):
                     "Auth completed with creds: %r. Client dict has keys: %r",
                     creds, clientdict.keys()
                 )
-                defer.returnValue((True, creds, clientdict, session['id']))
+                defer.returnValue((creds, clientdict, session['id']))
 
         ret = self._auth_dict_for_flows(flows, session)
         ret['completed'] = creds.keys()
         ret.update(errordict)
-        defer.returnValue((False, ret, clientdict, session['id']))
+        raise InteractiveAuthIncompleteError(
+            ret,
+        )
 
     @defer.inlineCallbacks
     def add_oob_auth(self, stagetype, authdict, clientip):