Revert "Add /logout route that clears site data via Clear-Site-Data (#112567)" (#113334)

This reverts commit 2871fbf.

Author: arthur791004

client/document/logout.jsx

@@ -28,17 +28,13 @@ import {
 	CIAB_DASHBOARD_SECTION_DEFINITION,
 	CIAB_DASHBOARD_SECTION_PATHS,
 } from 'calypso/dashboard/app-ciab/section';
-import {
-	buildDotcomDashboardLink,
-	isAllowedDotcomDashboardHostname,
-} from 'calypso/dashboard/app-dotcom/routing';
+import { isAllowedDotcomDashboardHostname } from 'calypso/dashboard/app-dotcom/routing';
 import {
 	DOTCOM_DASHBOARD_SECTION_DEFINITION,
 	DOTCOM_DASHBOARD_SECTION_PATHS,
 } from 'calypso/dashboard/app-dotcom/section';
 import { A4A_SIGNUP_PATHS } from 'calypso/dashboard/section';
 import isDashboardEnv from 'calypso/dashboard/utils/is-dashboard-env';
-import { wpcomLink } from 'calypso/dashboard/utils/link';
 import wooDnaConfig from 'calypso/jetpack-connect/woo-dna-config';
 import { STEPPER_SECTION_DEFINITION } from 'calypso/landing/stepper/section';
 import { SUBSCRIPTIONS_SECTION_DEFINITION } from 'calypso/landing/subscriptions/section';
@@ -1216,62 +1212,6 @@ function wpcomPages( app ) {
 	} );
 }
 
-/**
- * Resolve the counterpart origin's `/logout` URL for the cross-origin data clear.
- *
- * `Clear-Site-Data` for "storage"/"cache" is scoped to the origin that returns
- * it, and the classic Calypso app and the Dashboard are served from separate
- * origins (e.g. wordpress.com vs. my.wordpress.com). To clear both, `/logout`
- * embeds the counterpart origin's `/logout?embed=1` in a hidden iframe. Returns
- * `null` when there is no distinct counterpart (e.g. single-origin calypso.live).
- */
-function getCounterpartLogoutUrl( req ) {
-	if ( req.hostname.endsWith( '.calypso.live' ) ) {
-		return null;
-	}
-
-	if ( isAllowedDotcomDashboardHostname( req.hostname ) ) {
-		// On the Dashboard host, the classic Calypso origin is the counterpart.
-		// `wpcomLink` resolves it from the `wpcom_url` config (wordpress.com in
-		// production, the local Calypso dev server in development).
-		return wpcomLink( '/logout?embed=1' );
-	}
-
-	if ( [ 'wordpress.com', 'calypso.localhost' ].includes( req.hostname ) ) {
-		return buildDotcomDashboardLink( '/logout?embed=1' );
-	}
-
-	return null;
-}
-
-/**
- * Resolve the destination `/logout` sends the user to once data is cleared.
- *
- * Honors a `redirect_to` query param, but only for same-origin destinations —
- * returned as a relative path so the client-side redirect can never leave this
- * origin (guards against open redirects). Anything else falls back to `/log-in`.
- */
-function getLogoutRedirectTo( req ) {
-	const target = req.query.redirect_to;
-	if ( typeof target !== 'string' || ! target ) {
-		return '/log-in';
-	}
-
-	const host = req.get( 'host' );
-	try {
-		const resolved = new URL( target, `https://${ host }` );
-		const destination = resolved.pathname + resolved.search + resolved.hash;
-		// Reject cross-origin and protocol-relative (`//host`) destinations.
-		if ( resolved.host === host && ! destination.startsWith( '//' ) ) {
-			return destination;
-		}
-	} catch {
-		// Fall through to the default.
-	}
-
-	return '/log-in';
-}
-
 export default function pages() {
 	const app = express();
 
@@ -1284,30 +1224,6 @@ export default function pages() {
 	app.use( setupLoggedInContext );
 	app.use( middlewareUnsupportedBrowser() );
 
-	// `/logout` clears browser-stored site data for the current origin via the
-	// `Clear-Site-Data` response header, then best-effort clears the counterpart
-	// origin (classic Calypso <-> Dashboard) through a hidden iframe before
-	// redirecting to the login page. Actual session invalidation is handled by the
-	// client logout flow. Registered before section routing so it responds on both
-	// the classic Calypso and Dashboard hostnames.
-	app.get( '/logout', ( req, res ) => {
-		res.set( 'Clear-Site-Data', '"storage", "cache", "cookies"' );
-
-		if ( req.query.embed ) {
-			// Loaded inside the counterpart origin's iframe: this response only needs
-			// to carry the header, so render an empty page and stop here.
-			res.send( renderJsx( 'logout', { embed: true } ) );
-			return;
-		}
-
-		res.send(
-			renderJsx( 'logout', {
-				iframeSrc: getCounterpartLogoutUrl( req ),
-				redirectTo: getLogoutRedirectTo( req ),
-			} )
-		);
-	} );
-
 	if ( ! ( isJetpackCloud() || isA8CForAgencies() || isDashboardEnv() ) ) {
 		wpcomPages( app );
 	}