Default value for `public_baseurl` (#11210)

We might as well use a default value for `public_baseurl` based on
`server_name` - in many cases, it will be correct.

1 files changed, 3 insertions, 7 deletions

diff --git a/synapse/config/cas.py b/synapse/config/cas.py

index 9b58ecf3d8..3f81814043 100644
--- a/synapse/config/cas.py
+++ b/synapse/config/cas.py
@@ -16,7 +16,7 @@ from typing import Any, List
 
 from synapse.config.sso import SsoAttributeRequirement
 
-from ._base import Config, ConfigError
+from ._base import Config
 from ._util import validate_config
 
 
@@ -35,14 +35,10 @@ class CasConfig(Config):
         if self.cas_enabled:
             self.cas_server_url = cas_config["server_url"]
 
-            # The public baseurl is required because it is used by the redirect
-            # template.
-            public_baseurl = self.root.server.public_baseurl
-            if not public_baseurl:
-                raise ConfigError("cas_config requires a public_baseurl to be set")
-
             # TODO Update this to a _synapse URL.
+            public_baseurl = self.root.server.public_baseurl
             self.cas_service_url = public_baseurl + "_matrix/client/r0/login/cas/ticket"
+
             self.cas_displayname_attribute = cas_config.get("displayname_attribute")
             required_attributes = cas_config.get("required_attributes") or {}
             self.cas_required_attributes = _parsed_required_attributes_def(