Implement .well-known handling (#4262)

Sometimes it's useful for synapse to generate its own .well-known file.

changelog.d/4262.feature

@@ -0,0 +1 @@
+Support for serving .well-known files

synapse/app/homeserver.py

@@ -60,6 +60,7 @@
 from synapse.rest import ClientRestResource
 from synapse.rest.key.v2 import KeyApiV2Resource
 from synapse.rest.media.v0.content_repository import ContentRepoResource
+from synapse.rest.well_known import WellKnownResource
 from synapse.server import HomeServer
 from synapse.storage import DataStore, are_all_users_on_domain
 from synapse.storage.engines import IncorrectDatabaseSetup, create_engine
@@ -195,6 +196,7 @@ def _configure_named_resource(self, name, compress=False):
                 "/_matrix/client/unstable": client_resource,
                 "/_matrix/client/v2_alpha": client_resource,
                 "/_matrix/client/versions": client_resource,
+                "/.well-known/matrix/client": WellKnownResource(self),
             })
 
         if name == "consent":

synapse/config/registration.py

@@ -37,6 +37,7 @@ def read_config(self, config):
 
         self.bcrypt_rounds = config.get("bcrypt_rounds", 12)
         self.trusted_third_party_id_servers = config["trusted_third_party_id_servers"]
+        self.default_identity_server = config.get("default_identity_server")
         self.allow_guest_access = config.get("allow_guest_access", False)
 
         self.invite_3pid_guest = (
@@ -91,6 +92,14 @@ def default_config(self, **kwargs):
         # accessible to anonymous users.
         allow_guest_access: False
 
+        # The identity server which we suggest that clients should use when users log
+        # in on this server.
+        #
+        # (By default, no suggestion is made, so it is left up to the client.
+        # This setting is ignored unless public_baseurl is also set.)
+        #
+        # default_identity_server: https://matrix.org
+
         # The list of identity servers trusted to verify third party
         # identifiers by this server.
         #

synapse/rest/well_known.py

@@ -0,0 +1,70 @@
+# -*- coding: utf-8 -*-
+# Copyright 2018 New Vector Ltd.
+#
+# 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.
+
+import json
+import logging
+
+from twisted.web.resource import Resource
+
+logger = logging.getLogger(__name__)
+
+
+class WellKnownBuilder(object):
+    """Utility to construct the well-known response
+
+    Args:
+        hs (synapse.server.HomeServer):
+    """
+    def __init__(self, hs):
+        self._config = hs.config
+
+    def get_well_known(self):
+        # if we don't have a public_base_url, we can't help much here.
+        if self._config.public_baseurl is None:
+            return None
+
+        result = {
+            "m.homeserver": {
+                "base_url": self._config.public_baseurl,
+            },
+        }
+
+        if self._config.default_identity_server:
+            result["m.identity_server"] = {
+                "base_url": self._config.default_identity_server,
+            }
+
+        return result
+
+
+class WellKnownResource(Resource):
+    """A Twisted web resource which renders the .well-known file"""
+
+    isLeaf = 1
+
+    def __init__(self, hs):
+        Resource.__init__(self)
+        self._well_known_builder = WellKnownBuilder(hs)
+
+    def render_GET(self, request):
+        r = self._well_known_builder.get_well_known()
+        if not r:
+            request.setResponseCode(404)
+            request.setHeader(b"Content-Type", b"text/plain")
+            return b'.well-known not available'
+
+        logger.error("returning: %s", r)
+        request.setHeader(b"Content-Type", b"application/json")
+        return json.dumps(r).encode("utf-8")

tests/rest/test_well_known.py

@@ -0,0 +1,58 @@
+# -*- coding: utf-8 -*-
+# Copyright 2018 New Vector
+#
+# 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.
+
+
+from synapse.rest.well_known import WellKnownResource
+
+from tests import unittest
+
+
+class WellKnownTests(unittest.HomeserverTestCase):
+    def setUp(self):
+        super(WellKnownTests, self).setUp()
+
+        # replace the JsonResource with a WellKnownResource
+        self.resource = WellKnownResource(self.hs)
+
+    def test_well_known(self):
+        self.hs.config.public_baseurl = "https://tesths"
+        self.hs.config.default_identity_server = "https://testis"
+
+        request, channel = self.make_request(
+            "GET",
+            "/.well-known/matrix/client",
+            shorthand=False,
+        )
+        self.render(request)
+
+        self.assertEqual(request.code, 200)
+        self.assertEqual(
+            channel.json_body, {
+                "m.homeserver": {"base_url": "https://tesths"},
+                "m.identity_server": {"base_url": "https://testis"},
+            }
+        )
+
+    def test_well_known_no_public_baseurl(self):
+        self.hs.config.public_baseurl = None
+
+        request, channel = self.make_request(
+            "GET",
+            "/.well-known/matrix/client",
+            shorthand=False,
+        )
+        self.render(request)
+
+        self.assertEqual(request.code, 404)