Merge pull request #649 from matrix-org/dbkr/idempotent_registration

Make registration idempotent

2 files changed, 28 insertions, 2 deletions

diff --git a/synapse/rest/client/v2_alpha/account.py b/synapse/rest/client/v2_alpha/account.py
index dd4ea45588..7f8a6a4cf7 100644
--- a/synapse/rest/client/v2_alpha/account.py
+++ b/synapse/rest/client/v2_alpha/account.py
@@ -43,7 +43,7 @@ class PasswordRestServlet(RestServlet):
 
         body = parse_json_object_from_request(request)
 
-        authed, result, params = yield self.auth_handler.check_auth([
+        authed, result, params, _ = yield self.auth_handler.check_auth([
             [LoginType.PASSWORD],
             [LoginType.EMAIL_IDENTITY]
         ], body, self.hs.get_ip_from_request(request))
diff --git a/synapse/rest/client/v2_alpha/register.py b/synapse/rest/client/v2_alpha/register.py
index 533ff136eb..c440430e25 100644
--- a/synapse/rest/client/v2_alpha/register.py
+++ b/synapse/rest/client/v2_alpha/register.py
@@ -139,7 +139,7 @@ class RegisterRestServlet(RestServlet):
                 [LoginType.EMAIL_IDENTITY]
             ]
 
-        authed, result, params = yield self.auth_handler.check_auth(
+        authed, result, params, session_id = yield self.auth_handler.check_auth(
             flows, body, self.hs.get_ip_from_request(request)
         )
 
@@ -147,6 +147,26 @@ class RegisterRestServlet(RestServlet):
             defer.returnValue((401, result))
             return
 
+        # have we already registered a user for this session
+        registered_user_id = self.auth_handler.get_session_data(
+            session_id, "registered_user_id", None
+        )
+        if registered_user_id is not None:
+            logger.info(
+                "Already registered user ID %r for this session",
+                registered_user_id
+            )
+            access_token = yield self.auth_handler.issue_access_token(registered_user_id)
+            refresh_token = yield self.auth_handler.issue_refresh_token(
+                registered_user_id
+            )
+            defer.returnValue((200, {
+                "user_id": registered_user_id,
+                "access_token": access_token,
+                "home_server": self.hs.hostname,
+                "refresh_token": refresh_token,
+            }))
+
         # NB: This may be from the auth handler and NOT from the POST
         if 'password' not in params:
             raise SynapseError(400, "Missing password.", Codes.MISSING_PARAM)
@@ -161,6 +181,12 @@ class RegisterRestServlet(RestServlet):
             guest_access_token=guest_access_token,
         )
 
+        # remember that we've now registered that user account, and with what
+        # user ID (since the user may not have specified)
+        self.auth_handler.set_session_data(
+            session_id, "registered_user_id", user_id
+        )
+
         if result and LoginType.EMAIL_IDENTITY in result:
             threepid = result[LoginType.EMAIL_IDENTITY]