Revert "Redirect redirect requests if they arrive on the wrong URI"

This reverts commit 5ee8a1c50a.

This has now been superceded on develop by PR #9436.

synapse/rest/client/v1/login.py

@@ -354,7 +354,6 @@ class SsoRedirectServlet(RestServlet):
             hs.get_oidc_handler()
         self._sso_handler = hs.get_sso_handler()
         self._msc2858_enabled = hs.config.experimental.msc2858_enabled
-        self._public_baseurl = hs.config.public_baseurl
 
     def register(self, http_server: HttpServer) -> None:
         super().register(http_server)
@@ -374,28 +373,6 @@ class SsoRedirectServlet(RestServlet):
     async def on_GET(
         self, request: SynapseRequest, idp_id: Optional[str] = None
     ) -> None:
-        if not self._public_baseurl:
-            raise SynapseError(400, "SSO requires a valid public_baseurl")
-
-        # if this isn't the expected hostname, redirect to the right one, so that we
-        # get our cookies back.
-        requested_uri = b"%s://%s%s" % (
-            b"https" if request.isSecure() else b"http",
-            request.getHeader(b"host"),
-            request.uri,
-        )
-        baseurl_bytes = self._public_baseurl.encode("utf-8")
-        if not requested_uri.startswith(baseurl_bytes):
-            i = requested_uri.index(b"/_matrix")
-            new_uri = baseurl_bytes[:-1] + requested_uri[i:]
-            logger.info(
-                "Requested URI %s is not canonical: redirecting to %s",
-                requested_uri.decode("utf-8", errors="replace"),
-                new_uri.decode("utf-8", errors="replace"),
-            )
-            request.redirect(new_uri)
-            finish_request(request)
-
         client_redirect_url = parse_string(
             request, "redirectUrl", required=True, encoding=None
         )