Remove support for the webclient listener. (#11895)

Also remove support for non-HTTP(S) web_client_location.

6 files changed, 29 insertions, 176 deletions

diff --git a/changelog.d/11895.removal b/changelog.d/11895.removal
new file mode 100644
index 0000000000..5973d96a33
--- /dev/null
+++ b/changelog.d/11895.removal
@@ -0,0 +1 @@
+Drop support for `webclient` listeners and configuring `web_client_location` to a non-HTTP(S) URL. Deprecated configurations are a configuration error.
diff --git a/docs/upgrade.md b/docs/upgrade.md
index f455d257ba..7d582af0a7 100644
--- a/docs/upgrade.md
+++ b/docs/upgrade.md
@@ -85,6 +85,19 @@ process, for example:
     dpkg -i matrix-synapse-py3_1.3.0+stretch1_amd64.deb
     ```
 
+# Upgrading to v1.53.0
+
+## Dropping support for `webclient` listeners and non-HTTP(S) `web_client_location`
+
+Per the deprecation notice in Synapse v1.51.0, listeners of type  `webclient`
+are no longer supported and configuring them is a now a configuration error.
+
+Configuring a non-HTTP(S) `web_client_location` configuration is is now a
+configuration error. Since the `webclient` listener is no longer supported, this
+setting only applies to the root path `/` of Synapse's web server and no longer
+the `/_matrix/client/` path.
+
+
 # Upgrading to v1.51.0
 
 ## Deprecation of `webclient` listeners and non-HTTP(S) `web_client_location`
diff --git a/synapse/api/urls.py b/synapse/api/urls.py
index f9f9467dc1..bd49fa6a5f 100644
--- a/synapse/api/urls.py
+++ b/synapse/api/urls.py
@@ -28,7 +28,6 @@ FEDERATION_V1_PREFIX = FEDERATION_PREFIX + "/v1"
 FEDERATION_V2_PREFIX = FEDERATION_PREFIX + "/v2"
 FEDERATION_UNSTABLE_PREFIX = FEDERATION_PREFIX + "/unstable"
 STATIC_PREFIX = "/_matrix/static"
-WEB_CLIENT_PREFIX = "/_matrix/client"
 SERVER_KEY_V2_PREFIX = "/_matrix/key/v2"
 MEDIA_R0_PREFIX = "/_matrix/media/r0"
 MEDIA_V3_PREFIX = "/_matrix/media/v3"
diff --git a/synapse/app/homeserver.py b/synapse/app/homeserver.py
index efedcc8889..24d55b0494 100644
--- a/synapse/app/homeserver.py
+++ b/synapse/app/homeserver.py
@@ -21,7 +21,6 @@ from typing import Dict, Iterable, Iterator, List
 from twisted.internet.tcp import Port
 from twisted.web.resource import EncodingResourceWrapper, Resource
 from twisted.web.server import GzipEncoderFactory
-from twisted.web.static import File
 
 import synapse
 import synapse.config.logger
@@ -33,7 +32,6 @@ from synapse.api.urls import (
     MEDIA_V3_PREFIX,
     SERVER_KEY_V2_PREFIX,
     STATIC_PREFIX,
-    WEB_CLIENT_PREFIX,
 )
 from synapse.app import _base
 from synapse.app._base import (
@@ -53,7 +51,6 @@ from synapse.http.additional_resource import AdditionalResource
 from synapse.http.server import (
     OptionsResource,
     RootOptionsRedirectResource,
-    RootRedirect,
     StaticResource,
 )
 from synapse.http.site import SynapseSite
@@ -134,15 +131,12 @@ class SynapseHomeServer(HomeServer):
         # Try to find something useful to serve at '/':
         #
         # 1. Redirect to the web client if it is an HTTP(S) URL.
-        # 2. Redirect to the web client served via Synapse.
-        # 3. Redirect to the static "Synapse is running" page.
-        # 4. Do not redirect and use a blank resource.
-        if self.config.server.web_client_location_is_redirect:
+        # 2. Redirect to the static "Synapse is running" page.
+        # 3. Do not redirect and use a blank resource.
+        if self.config.server.web_client_location:
             root_resource: Resource = RootOptionsRedirectResource(
                 self.config.server.web_client_location
             )
-        elif WEB_CLIENT_PREFIX in resources:
-            root_resource = RootOptionsRedirectResource(WEB_CLIENT_PREFIX)
         elif STATIC_PREFIX in resources:
             root_resource = RootOptionsRedirectResource(STATIC_PREFIX)
         else:
@@ -270,28 +264,6 @@ class SynapseHomeServer(HomeServer):
         if name in ["keys", "federation"]:
             resources[SERVER_KEY_V2_PREFIX] = KeyApiV2Resource(self)
 
-        if name == "webclient":
-            # webclient listeners are deprecated as of Synapse v1.51.0, remove it
-            # in > v1.53.0.
-            webclient_loc = self.config.server.web_client_location
-
-            if webclient_loc is None:
-                logger.warning(
-                    "Not enabling webclient resource, as web_client_location is unset."
-                )
-            elif self.config.server.web_client_location_is_redirect:
-                resources[WEB_CLIENT_PREFIX] = RootRedirect(webclient_loc)
-            else:
-                logger.warning(
-                    "Running webclient on the same domain is not recommended: "
-                    "https://github.com/matrix-org/synapse#security-note - "
-                    "after you move webclient to different host you can set "
-                    "web_client_location to its full URL to enable redirection."
-                )
-                # GZip is disabled here due to
-                # https://twistedmatrix.com/trac/ticket/7678
-                resources[WEB_CLIENT_PREFIX] = File(webclient_loc)
-
         if name == "metrics" and self.config.metrics.enable_metrics:
             resources[METRICS_PREFIX] = MetricsResource(RegistryProxy)
 
diff --git a/synapse/config/server.py b/synapse/config/server.py
index a0a00a9798..7bc9624546 100644
--- a/synapse/config/server.py
+++ b/synapse/config/server.py
@@ -179,7 +179,6 @@ KNOWN_RESOURCES = {
     "openid",
     "replication",
     "static",
-    "webclient",
 }
 
 
@@ -519,16 +518,12 @@ class ServerConfig(Config):
             self.listeners = l2
 
         self.web_client_location = config.get("web_client_location", None)
-        self.web_client_location_is_redirect = self.web_client_location and (
+        # Non-HTTP(S) web client location is not supported.
+        if self.web_client_location and not (
             self.web_client_location.startswith("http://")
             or self.web_client_location.startswith("https://")
-        )
-        # A non-HTTP(S) web client location is deprecated.
-        if self.web_client_location and not self.web_client_location_is_redirect:
-            logger.warning(NO_MORE_NONE_HTTP_WEB_CLIENT_LOCATION_WARNING)
-
-        # Warn if webclient is configured for a worker.
-        _warn_if_webclient_configured(self.listeners)
+        ):
+            raise ConfigError("web_client_location must point to a HTTP(S) URL.")
 
         self.gc_thresholds = read_gc_thresholds(config.get("gc_thresholds", None))
         self.gc_seconds = self.read_gc_intervals(config.get("gc_min_interval", None))
@@ -1351,11 +1346,16 @@ def parse_listener_def(listener: Any) -> ListenerConfig:
 
     http_config = None
     if listener_type == "http":
+        try:
+            resources = [
+                HttpResourceConfig(**res) for res in listener.get("resources", [])
+            ]
+        except ValueError as e:
+            raise ConfigError("Unknown listener resource") from e
+
         http_config = HttpListenerConfig(
             x_forwarded=listener.get("x_forwarded", False),
-            resources=[
-                HttpResourceConfig(**res) for res in listener.get("resources", [])
-            ],
+            resources=resources,
             additional_resources=listener.get("additional_resources", {}),
             tag=listener.get("tag"),
         )
@@ -1363,30 +1363,6 @@ def parse_listener_def(listener: Any) -> ListenerConfig:
     return ListenerConfig(port, bind_addresses, listener_type, tls, http_config)
 
 
-NO_MORE_NONE_HTTP_WEB_CLIENT_LOCATION_WARNING = """
-Synapse no longer supports serving a web client. To remove this warning,
-configure 'web_client_location' with an HTTP(S) URL.
-"""
-
-
-NO_MORE_WEB_CLIENT_WARNING = """
-Synapse no longer includes a web client. To redirect the root resource to a web client, configure
-'web_client_location'. To remove this warning, remove 'webclient' from the 'listeners'
-configuration.
-"""
-
-
-def _warn_if_webclient_configured(listeners: Iterable[ListenerConfig]) -> None:
-    for listener in listeners:
-        if not listener.http_options:
-            continue
-        for res in listener.http_options.resources:
-            for name in res.names:
-                if name == "webclient":
-                    logger.warning(NO_MORE_WEB_CLIENT_WARNING)
-                    return
-
-
 _MANHOLE_SETTINGS_SCHEMA = {
     "type": "object",
     "properties": {
diff --git a/tests/http/test_webclient.py b/tests/http/test_webclient.py
deleted file mode 100644
index ee5cf299f6..0000000000
--- a/tests/http/test_webclient.py
+++ /dev/null
@@ -1,108 +0,0 @@
-# Copyright 2022 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.
-from http import HTTPStatus
-from typing import Dict
-
-from twisted.web.resource import Resource
-
-from synapse.app.homeserver import SynapseHomeServer
-from synapse.config.server import HttpListenerConfig, HttpResourceConfig, ListenerConfig
-from synapse.http.site import SynapseSite
-
-from tests.server import make_request
-from tests.unittest import HomeserverTestCase, create_resource_tree, override_config
-
-
-class WebClientTests(HomeserverTestCase):
-    @override_config(
-        {
-            "web_client_location": "https://example.org",
-        }
-    )
-    def test_webclient_resolves_with_client_resource(self):
-        """
-        Tests that both client and webclient resources can be accessed simultaneously.
-
-        This is a regression test created in response to https://github.com/matrix-org/synapse/issues/11763.
-        """
-        for resource_name_order_list in [
-            ["webclient", "client"],
-            ["client", "webclient"],
-        ]:
-            # Create a dictionary from path regex -> resource
-            resource_dict: Dict[str, Resource] = {}
-
-            for resource_name in resource_name_order_list:
-                resource_dict.update(
-                    SynapseHomeServer._configure_named_resource(self.hs, resource_name)
-                )
-
-            # Create a root resource which ties the above resources together into one
-            root_resource = Resource()
-            create_resource_tree(resource_dict, root_resource)
-
-            # Create a site configured with this resource to make HTTP requests against
-            listener_config = ListenerConfig(
-                port=8008,
-                bind_addresses=["127.0.0.1"],
-                type="http",
-                http_options=HttpListenerConfig(
-                    resources=[HttpResourceConfig(names=resource_name_order_list)]
-                ),
-            )
-            test_site = SynapseSite(
-                logger_name="synapse.access.http.fake",
-                site_tag=self.hs.config.server.server_name,
-                config=listener_config,
-                resource=root_resource,
-                server_version_string="1",
-                max_request_body_size=1234,
-                reactor=self.reactor,
-            )
-
-            # Attempt to make requests to endpoints on both the webclient and client resources
-            # on test_site.
-            self._request_client_and_webclient_resources(test_site)
-
-    def _request_client_and_webclient_resources(self, test_site: SynapseSite) -> None:
-        """Make a request to an endpoint on both the webclient and client-server resources
-        of the given SynapseSite.
-
-        Args:
-            test_site: The SynapseSite object to make requests against.
-        """
-
-        # Ensure that the *webclient* resource is behaving as expected (we get redirected to
-        # the configured web_client_location)
-        channel = make_request(
-            self.reactor,
-            site=test_site,
-            method="GET",
-            path="/_matrix/client",
-        )
-        # Check that we are being redirected to the webclient location URI.
-        self.assertEqual(channel.code, HTTPStatus.FOUND)
-        self.assertEqual(
-            channel.headers.getRawHeaders("Location"), ["https://example.org"]
-        )
-
-        # Ensure that a request to the *client* resource works.
-        channel = make_request(
-            self.reactor,
-            site=test_site,
-            method="GET",
-            path="/_matrix/client/v3/login",
-        )
-        self.assertEqual(channel.code, HTTPStatus.OK)
-        self.assertIn("flows", channel.json_body)