Fetch homeUrl from .well-known (#7790)

* Fetch homeUrl from .well-known

* homeUrl: prefer config.json over .well-known

* homeUrl: prefer deprecated config.json variant over .well-known

* Apply suggestions from code review

Co-authored-by: Michael Telatynski <7t3chguy@gmail.com>

Co-authored-by: Michael Telatynski <7t3chguy@gmail.com>
Co-authored-by: Travis Ralston <travisr@matrix.org>

src/utils/WellKnownUtils.ts

@@ -24,6 +24,7 @@ const E2EE_WK_KEY = "io.element.e2ee";
 const E2EE_WK_KEY_DEPRECATED = "im.vector.riot.e2ee";
 export const TILE_SERVER_WK_KEY = new UnstableValue(
     "m.tile_server", "org.matrix.msc3488.tile_server");
+const EMBEDDED_PAGES_WK_PROPERTY = "io.element.embedded_pages";
 
 /* eslint-disable camelcase */
 export interface ICallBehaviourWellKnown {
@@ -39,6 +40,10 @@ export interface IE2EEWellKnown {
 export interface ITileServerWellKnown {
     map_style_url?: string;
 }
+
+export interface IEmbeddedPagesWellKnown {
+    home_url?: string;
+}
 /* eslint-enable camelcase */
 
 export function getCallBehaviourWellKnown(): ICallBehaviourWellKnown {
@@ -70,6 +75,16 @@ export function tileServerFromWellKnown(
     );
 }
 
+export function getEmbeddedPagesWellKnown(): IEmbeddedPagesWellKnown | undefined {
+    return embeddedPagesFromWellKnown(MatrixClientPeg.get()?.getClientWellKnown());
+}
+
+export function embeddedPagesFromWellKnown(
+    clientWellKnown?: IClientWellKnown,
+): IEmbeddedPagesWellKnown {
+    return (clientWellKnown?.[EMBEDDED_PAGES_WK_PROPERTY]);
+}
+
 export function isSecureBackupRequired(): boolean {
     const wellKnown = getE2EEWellKnown();
     return wellKnown && wellKnown["secure_backup_required"] === true;

src/utils/pages.ts

@@ -17,6 +17,7 @@ limitations under the License.
 import { logger } from "matrix-js-sdk/src/logger";
 
 import { IConfigOptions } from "../IConfigOptions";
+import { getEmbeddedPagesWellKnown } from '../utils/WellKnownUtils';
 import { SnakedObject } from "./SnakedObject";
 
 export function getHomePageUrl(appConfig: IConfigOptions): string | null {
@@ -38,6 +39,10 @@ export function getHomePageUrl(appConfig: IConfigOptions): string | null {
         }
     }
 
+    if (!pageUrl) {
+        pageUrl = getEmbeddedPagesWellKnown()?.home_url;
+    }
+
     return pageUrl;
 }