Proper handling of auth site runtime change done via web interface, making the change immediately effective. Kept in origins list that is still also visible on the same dialog, where it can be removed if needed.

paskia/util/runtime.py

@@ -48,14 +48,20 @@ def update_runtime_config(new_config: Config) -> None:
         return  # No runtime config to update
 
     # Recompute site_url and site_path based on new config
-    site_path = "/" if new_config.auth_host else "/auth/"
+    old_auth_host = current_runtime.config.auth_host
     if new_config.auth_host:
-        site_url = new_config.auth_host
-    elif new_config.origins:
-        site_url = new_config.origins[0]
+        site_url, site_path = new_config.auth_host, "/"
     else:
-        # Keep current site_url if no auth_host and no origins
-        site_url = current_runtime.site_url
+        site_path = "/auth/"
+        # Never derive site_url from a just-removed auth host
+        origins = [o for o in (new_config.origins or []) if o != old_auth_host]
+        if origins:
+            site_url = origins[0]
+        elif current_runtime.site_url != old_auth_host:
+            # Keep current site_url if it wasn't derived from the removed auth host
+            site_url = current_runtime.site_url
+        else:
+            site_url = f"https://{new_config.rp_id}"
 
     new_runtime = RuntimeConfig(
         config=new_config,

tests/test_admin.py

@@ -37,7 +37,10 @@ from paskia.db import (
     create_user,
 )
 from paskia.db.operations import DB
+from paskia.util import hostutil
 from paskia.util.crypto import hash_secret
+from paskia.util.runtime import clear_config_cache
+from paskia.util.runtime import config as runtime_config
 from tests.conftest import auth_headers, create_test_image_bytes, create_test_session
 
 # -------------------- Additional Fixtures --------------------
@@ -1789,3 +1792,115 @@ class TestOrgAdminAuthExceptions:
             headers={**auth_headers(regular_session_token), "Host": "localhost:4401"},
         )
         assert response.status_code == 403
+
+
+class TestServerConfig:
+    """Tests for GET/PATCH /auth/api/admin/server-config/ runtime updates."""
+
+    @pytest.fixture(scope="function")
+    def restore_runtime_config(self):
+        """Restore PASKIA_CONFIG env and cache after a test mutates runtime."""
+        original = os.environ["PASKIA_CONFIG"]
+        yield
+        os.environ["PASKIA_CONFIG"] = original
+        clear_config_cache()
+
+    async def _set_auth_host(self, client, session_token, test_user, test_credential):
+        """Configure an auth host via PATCH, as the admin UI would."""
+        r = await client.patch(
+            "/auth/api/admin/server-config/",
+            json={
+                "rp_name": "",
+                "auth_host": "auth.localhost",
+                "origins": ["auth.localhost", "localhost"],
+            },
+            headers={**auth_headers(session_token), "Host": "localhost:4401"},
+        )
+        assert r.status_code == 200, r.text
+        assert db.data().config.auth_host == "https://auth.localhost"
+        assert hostutil.dedicated_auth_host() == "auth.localhost"
+        assert hostutil.auth_site_url() == "https://auth.localhost/"
+        # Session for requests coming from the auth host (sessions are host-bound)
+        _, token = create_test_session(
+            test_user.uuid, test_credential.uuid, host="auth.localhost"
+        )
+        return {**auth_headers(token), "Host": "auth.localhost"}
+
+    @pytest.mark.asyncio
+    async def test_remove_auth_host_updates_runtime(
+        self,
+        client: httpx.AsyncClient,
+        session_token: str,
+        test_user,
+        test_credential,
+        restore_runtime_config,
+    ):
+        """Removing auth_host must clear it from runtime config and URLs."""
+        headers = await self._set_auth_host(
+            client, session_token, test_user, test_credential
+        )
+
+        # The dialog still lists the old auth host among origins, so it is sent back
+        r = await client.patch(
+            "/auth/api/admin/server-config/",
+            json={
+                "rp_name": "",
+                "auth_host": "",
+                "origins": ["auth.localhost", "localhost"],
+            },
+            headers=headers,
+        )
+        assert r.status_code == 200, r.text
+        assert db.data().config.auth_host is None
+
+        rt = runtime_config()
+        assert rt.config.auth_host is None
+        assert rt.site_path == "/auth/"
+        assert "auth.localhost" not in rt.site_url
+        assert hostutil.dedicated_auth_host() is None
+        assert "auth.localhost" not in hostutil.auth_site_url()
+
+        # GET and settings reflect the cleared state
+        r = await client.get(
+            "/auth/api/admin/server-config/",
+            headers={**auth_headers(session_token), "Host": "localhost:4401"},
+        )
+        assert r.json()["auth_host"] == ""
+        r = await client.get("/auth/api/settings")
+        assert r.json()["auth_host"] is None
+        assert r.json()["ui_base_path"] == "/auth/"
+
+        # Middleware no longer redirects to the removed auth host
+        r = await client.get(
+            "/auth/admin",
+            headers={**auth_headers(session_token), "Host": "localhost:4401"},
+            follow_redirects=False,
+        )
+        assert "auth.localhost" not in r.headers.get("location", "")
+
+    @pytest.mark.asyncio
+    async def test_remove_auth_host_without_origins_falls_back_to_rp_id(
+        self,
+        client: httpx.AsyncClient,
+        session_token: str,
+        test_user,
+        test_credential,
+        restore_runtime_config,
+    ):
+        """With no origins left, site_url must not keep the removed auth host."""
+        headers = await self._set_auth_host(
+            client, session_token, test_user, test_credential
+        )
+
+        r = await client.patch(
+            "/auth/api/admin/server-config/",
+            json={"rp_name": "", "auth_host": "", "origins": []},
+            headers=headers,
+        )
+        assert r.status_code == 200, r.text
+
+        rt = runtime_config()
+        assert rt.config.auth_host is None
+        assert rt.site_path == "/auth/"
+        assert "auth.localhost" not in rt.site_url
+        assert "auth.localhost" not in hostutil.auth_site_url()