MOBILE-3694 iframe: Fix auto-login when there are several iframes

src/core/directives/format-text.ts

@@ -688,7 +688,10 @@ export class CoreFormatTextDirective implements OnChanges {
 
         if (currentSite?.containsUrl(src)) {
             // URL points to current site, try to use auto-login.
-            const finalUrl = await currentSite.getAutoLoginUrl(src, false);
+            // Remove iframe src, otherwise it can cause auto-login issues if there are several iframes with auto-login.
+            iframe.src = '';
+
+            const finalUrl = await CoreIframeUtils.getAutoLoginUrlForIframe(iframe, src);
             await CoreIframeUtils.fixIframeCookies(finalUrl);
 
             iframe.src = finalUrl;

src/core/services/utils/iframe.ts

@@ -23,7 +23,7 @@ import { CoreSites } from '@services/sites';
 import { CoreDomUtils } from '@services/utils/dom';
 import { CoreTextUtils } from '@services/utils/text';
 import { CoreUrlUtils } from '@services/utils/url';
-import { CoreUtils } from '@services/utils/utils';
+import { CoreUtils, PromiseDefer } from '@services/utils/utils';
 
 import { makeSingleton, Network, Platform, NgZone, Translate, Diagnostic } from '@singletons';
 import { CoreLogger } from '@singletons/logger';
@@ -48,6 +48,7 @@ export class CoreIframeUtilsProvider {
     static readonly FRAME_TAGS = ['iframe', 'frame', 'object', 'embed'];
 
     protected logger: CoreLogger;
+    protected waitAutoLoginDefer?: PromiseDefer<void>;
 
     constructor() {
         this.logger = CoreLogger.getInstance('CoreUtilsProvider');
@@ -182,6 +183,50 @@ export class CoreIframeUtilsProvider {
         element.parentElement?.insertBefore(div, element);
     }
 
+    /**
+     * Get auto-login URL for an iframe.
+     *
+     * @param iframe Iframe element.
+     * @param url Original URL.
+     * @return Promise resolved with the URL.
+     */
+    async getAutoLoginUrlForIframe(iframe: HTMLIFrameElement, url: string): Promise<string> {
+        const currentSite = CoreSites.getCurrentSite();
+        if (!currentSite) {
+            return url;
+        }
+
+        if (this.waitAutoLoginDefer) {
+            // Another iframe is already using auto-login. Wait for it to finish.
+            await this.waitAutoLoginDefer.promise;
+
+            // Return the original URL, we can't request a new auto-login.
+            return url;
+        }
+
+        // First iframe requesting auto-login.
+        this.waitAutoLoginDefer = CoreUtils.promiseDefer();
+
+        const finalUrl = await currentSite.getAutoLoginUrl(url, false);
+
+        // Resolve the promise once the iframe is loaded, or after a certain time.
+        let unblocked = false;
+        const unblock = () => {
+            if (unblocked) {
+                return;
+            }
+
+            unblocked = true;
+            this.waitAutoLoginDefer!.resolve();
+            delete this.waitAutoLoginDefer;
+        };
+
+        iframe.addEventListener('load', () => unblock());
+        setTimeout(() => unblock(), 15000);
+
+        return finalUrl;
+    }
+
     /**
      * Given an element, return the content window and document.
      * Please notice that the element should be an iframe, embed or similar.