Add a callback to react to 3PID associations (#12302)

changelog.d/12302.feature

+Add a module callback to react to new 3PID (email address, phone number) associations.

docs/modules/third_party_rules_callbacks.md

@@ -247,6 +247,24 @@ admin API.
 
 If multiple modules implement this callback, Synapse runs them all in order.
 
+### `on_threepid_bind`
+
+_First introduced in Synapse v1.56.0_
+
+```python
+async def on_threepid_bind(user_id: str, medium: str, address: str) -> None:
+```
+
+Called after creating an association between a local user and a third-party identifier
+(email address, phone number). The module is given the Matrix ID of the user the
+association is for, as well as the medium (`email` or `msisdn`) and address of the
+third-party identifier.
+
+Note that this callback is _not_ called after a successful association on an _identity
+server_.
+
+If multiple modules implement this callback, Synapse runs them all in order.
+
 ## Example
 
 The example below is a module that implements the third-party rules callback

synapse/events/third_party_rules.py

@@ -42,6 +42,7 @@ CHECK_CAN_SHUTDOWN_ROOM_CALLBACK = Callable[[str, str], Awaitable[bool]]
 CHECK_CAN_DEACTIVATE_USER_CALLBACK = Callable[[str, bool], Awaitable[bool]]
 ON_PROFILE_UPDATE_CALLBACK = Callable[[str, ProfileInfo, bool, bool], Awaitable]
 ON_USER_DEACTIVATION_STATUS_CHANGED_CALLBACK = Callable[[str, bool, bool], Awaitable]
+ON_THREEPID_BIND_CALLBACK = Callable[[str, str, str], Awaitable]
 
 
 def load_legacy_third_party_event_rules(hs: "HomeServer") -> None:
@@ -169,6 +170,7 @@ class ThirdPartyEventRules:
         self._on_user_deactivation_status_changed_callbacks: List[
             ON_USER_DEACTIVATION_STATUS_CHANGED_CALLBACK
         ] = []
+        self._on_threepid_bind_callbacks: List[ON_THREEPID_BIND_CALLBACK] = []
 
     def register_third_party_rules_callbacks(
         self,
@@ -187,6 +189,7 @@ class ThirdPartyEventRules:
         on_user_deactivation_status_changed: Optional[
             ON_USER_DEACTIVATION_STATUS_CHANGED_CALLBACK
         ] = None,
+        on_threepid_bind: Optional[ON_THREEPID_BIND_CALLBACK] = None,
     ) -> None:
         """Register callbacks from modules for each hook."""
         if check_event_allowed is not None:
@@ -221,6 +224,9 @@ class ThirdPartyEventRules:
                 on_user_deactivation_status_changed,
             )
 
+        if on_threepid_bind is not None:
+            self._on_threepid_bind_callbacks.append(on_threepid_bind)
+
     async def check_event_allowed(
         self, event: EventBase, context: EventContext
     ) -> Tuple[bool, Optional[dict]]:
@@ -479,3 +485,23 @@ class ThirdPartyEventRules:
                 logger.exception(
                     "Failed to run module API callback %s: %s", callback, e
                 )
+
+    async def on_threepid_bind(self, user_id: str, medium: str, address: str) -> None:
+        """Called after a threepid association has been verified and stored.
+
+        Note that this callback is called when an association is created on the
+        local homeserver, not when it's created on an identity server (and then kept track
+        of so that it can be unbound on the same IS later on).
+
+        Args:
+            user_id: the user being associated with the threepid.
+            medium: the threepid's medium.
+            address: the threepid's address.
+        """
+        for callback in self._on_threepid_bind_callbacks:
+            try:
+                await callback(user_id, medium, address)
+            except Exception as e:
+                logger.exception(
+                    "Failed to run module API callback %s: %s", callback, e
+                )

synapse/handlers/auth.py

@@ -211,6 +211,7 @@ class AuthHandler:
         self.macaroon_gen = hs.get_macaroon_generator()
         self._password_enabled = hs.config.auth.password_enabled
         self._password_localdb_enabled = hs.config.auth.password_localdb_enabled
+        self._third_party_rules = hs.get_third_party_event_rules()
 
         # Ratelimiter for failed auth during UIA. Uses same ratelimit config
         # as per `rc_login.failed_attempts`.
@@ -1505,6 +1506,8 @@ class AuthHandler:
             user_id, medium, address, validated_at, self.hs.get_clock().time_msec()
         )
 
+        await self._third_party_rules.on_threepid_bind(user_id, medium, address)
+
     async def delete_threepid(
         self, user_id: str, medium: str, address: str, id_server: Optional[str] = None
     ) -> bool:

synapse/module_api/__init__.py

@@ -62,6 +62,7 @@ from synapse.events.third_party_rules import (
     ON_CREATE_ROOM_CALLBACK,
     ON_NEW_EVENT_CALLBACK,
     ON_PROFILE_UPDATE_CALLBACK,
+    ON_THREEPID_BIND_CALLBACK,
     ON_USER_DEACTIVATION_STATUS_CHANGED_CALLBACK,
 )
 from synapse.handlers.account_validity import (
@@ -293,6 +294,7 @@ class ModuleApi:
         on_user_deactivation_status_changed: Optional[
             ON_USER_DEACTIVATION_STATUS_CHANGED_CALLBACK
         ] = None,
+        on_threepid_bind: Optional[ON_THREEPID_BIND_CALLBACK] = None,
     ) -> None:
         """Registers callbacks for third party event rules capabilities.
 
@@ -308,6 +310,7 @@ class ModuleApi:
             check_can_deactivate_user=check_can_deactivate_user,
             on_profile_update=on_profile_update,
             on_user_deactivation_status_changed=on_user_deactivation_status_changed,
+            on_threepid_bind=on_threepid_bind,
         )
 
     def register_presence_router_callbacks(

tests/rest/client/test_third_party_rules.py

@@ -896,3 +896,44 @@ class ThirdPartyRulesTestCase(unittest.FederatingHomeserverTestCase):
 
         # Check that the mock was called with the right room ID
         self.assertEqual(args[1], self.room_id)
+
+    def test_on_threepid_bind(self) -> None:
+        """Tests that the on_threepid_bind module callback is called correctly after
+        associating a 3PID to an account.
+        """
+        # Register a mocked callback.
+        threepid_bind_mock = Mock(return_value=make_awaitable(None))
+        third_party_rules = self.hs.get_third_party_event_rules()
+        third_party_rules._on_threepid_bind_callbacks.append(threepid_bind_mock)
+
+        # Register an admin user.
+        self.register_user("admin", "password", admin=True)
+        admin_tok = self.login("admin", "password")
+
+        # Also register a normal user we can modify.
+        user_id = self.register_user("user", "password")
+
+        # Add a 3PID to the user.
+        channel = self.make_request(
+            "PUT",
+            "/_synapse/admin/v2/users/%s" % user_id,
+            {
+                "threepids": [
+                    {
+                        "medium": "email",
+                        "address": "foo@example.com",
+                    },
+                ],
+            },
+            access_token=admin_tok,
+        )
+
+        # Check that the shutdown was blocked
+        self.assertEqual(channel.code, 200, channel.json_body)
+
+        # Check that the mock was called once.
+        threepid_bind_mock.assert_called_once()
+        args = threepid_bind_mock.call_args[0]
+
+        # Check that the mock was called with the right parameters
+        self.assertEqual(args, (user_id, "email", "foo@example.com"))