MSC2918 Refresh tokens implementation (#9450)

This implements refresh tokens, as defined by MSC2918

This MSC has been implemented client side in Hydrogen Web: vector-im/hydrogen-web#235

The basics of the MSC works: requesting refresh tokens on login, having the access tokens expire, and using the refresh token to get a new one.

Signed-off-by: Quentin Gliech <quentingliech@gmail.com>

synapse/storage/schema/main/delta/59/14refresh_tokens.sql

@@ -0,0 +1,34 @@
+/* Copyright 2021 The Matrix.org Foundation C.I.C
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+-- Holds MSC2918 refresh tokens
+CREATE TABLE refresh_tokens (
+  id BIGINT PRIMARY KEY,
+  user_id TEXT NOT NULL,
+  device_id TEXT NOT NULL,
+  token TEXT NOT NULL,
+  -- When consumed, a new refresh token is generated, which is tracked by
+  -- this foreign key
+  next_token_id BIGINT REFERENCES refresh_tokens (id) ON DELETE CASCADE,
+  UNIQUE(token)
+);
+
+-- Add a reference to the refresh token generated alongside each access token
+ALTER TABLE "access_tokens"
+  ADD COLUMN refresh_token_id BIGINT REFERENCES refresh_tokens (id) ON DELETE CASCADE;
+
+-- Add a flag whether the token was already used or not
+ALTER TABLE "access_tokens"
+  ADD COLUMN used BOOLEAN;