MOBILE-2653 iframe: Display warning in offline if needed

scripts/langindex.json

@@ -1403,6 +1403,7 @@
   "core.more": "moodle",
   "core.mygroups": "group",
   "core.name": "moodle",
+  "core.networkerroriframemsg": "local_moodlemobileapp",
   "core.networkerrormsg": "local_moodlemobileapp",
   "core.never": "moodle",
   "core.next": "moodle",

src/app/app.scss

@@ -941,6 +941,10 @@ ion-app.app-root {
   &.disable-scroll ion-modal .ion-page {
     pointer-events: initial;
   }
+
+  .core-iframe-offline-disabled {
+    display: none !important;
+  }
 }
 
 @each $color-name, $color-base, $color-contrast in get-colors($colors) {

src/components/icon/icon.ts

@@ -66,7 +66,20 @@ export class CoreIconComponent implements OnInit {
 
         const attrs = this.element.attributes;
         for (let i = attrs.length - 1; i >= 0; i--) {
-            newElement.setAttribute(attrs[i].name, attrs[i].value);
+            if (attrs[i].name == 'class') {
+                // We don't want to override the classes we already added. Add them one by one.
+                if (attrs[i].value) {
+                    const classes = attrs[i].value.split(' ');
+                    for (let j = 0; j < classes.length; j++) {
+                        if (classes[j]) {
+                            newElement.classList.add(classes[j]);
+                        }
+                    }
+                }
+
+            } else {
+                newElement.setAttribute(attrs[i].name, attrs[i].value);
+            }
         }
 
         this.element.parentElement.replaceChild(newElement, this.element);
@@ -79,12 +92,12 @@ export class CoreIconComponent implements OnInit {
      * @return {boolean}     If has a value equivalent to true.
      */
     isTrueProperty(val: any): boolean {
-      if (typeof val === 'string') {
+        if (typeof val === 'string') {
-          val = val.toLowerCase().trim();
+            val = val.toLowerCase().trim();
 
-          return (val === 'true' || val === 'on' || val === '');
+            return (val === 'true' || val === 'on' || val === '');
-      }
+        }
 
-      return !!val;
+        return !!val;
   }
 }

src/lang/en.json

@@ -153,6 +153,7 @@
     "mygroups": "My groups",
     "name": "Name",
     "nograde": "No grade",
+    "networkerroriframemsg": "This content is not available offline. Please connect to the internet and try again.",
     "networkerrormsg": "There was a problem connecting to the site. Please check your connection and try again.",
     "never": "Never",
     "next": "Next",

src/providers/utils/dom.ts

@@ -429,6 +429,18 @@ export class CoreDomUtilsProvider {
         return parseInt(style[measure], 10) || 0;
     }
 
+    /**
+     * Get the HTML code to render a connection warning icon.
+     *
+     * @return {string} HTML Code.
+     */
+    getConnectionWarningIconHtml(): string {
+        return '<div text-center><span class="core-icon-with-badge">' +
+                '<ion-icon role="img" class="icon fa fa-wifi" aria-label="wifi"></ion-icon>' +
+                '<ion-icon class="icon fa fa-exclamation-triangle core-icon-badge"></ion-icon>' +
+            '</span></div>';
+    }
+
     /**
      * Returns width of an element.
      *
@@ -500,12 +512,9 @@ export class CoreDomUtilsProvider {
      */
     private getErrorTitle(message: string): any {
         if (message == this.translate.instant('core.networkerrormsg') ||
-            message == this.translate.instant('core.fileuploader.errormustbeonlinetoupload')) {
+                message == this.translate.instant('core.fileuploader.errormustbeonlinetoupload')) {
-            return this.sanitizer.bypassSecurityTrustHtml('<div text-center><span class="core-icon-with-badge">' +
-                    '<ion-icon role="img" class="icon fa fa-wifi" aria-label="wifi"></ion-icon>' +
-                    '<ion-icon class="icon fa fa-exclamation-triangle core-icon-badge"></ion-icon>' +
-                '</span></div>');
 
+            return this.sanitizer.bypassSecurityTrustHtml(this.getConnectionWarningIconHtml());
         }
 
         return this.textUtils.decodeHTML(this.translate.instant('core.error'));

src/providers/utils/iframe.ts

@@ -12,8 +12,11 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-import { Injectable } from '@angular/core';
+import { Injectable, NgZone } from '@angular/core';
 import { Platform } from 'ionic-angular';
+import { TranslateService } from '@ngx-translate/core';
+import { Network } from '@ionic-native/network';
+import { CoreAppProvider } from '../app';
 import { CoreFileProvider } from '../file';
 import { CoreLoggerProvider } from '../logger';
 import { CoreSitesProvider } from '../sites';
@@ -33,10 +36,75 @@ export class CoreIframeUtilsProvider {
 
     constructor(logger: CoreLoggerProvider, private fileProvider: CoreFileProvider, private sitesProvider: CoreSitesProvider,
             private urlUtils: CoreUrlUtilsProvider, private textUtils: CoreTextUtilsProvider, private utils: CoreUtilsProvider,
-            private domUtils: CoreDomUtilsProvider, private platform: Platform) {
+            private domUtils: CoreDomUtilsProvider, private platform: Platform, private appProvider: CoreAppProvider,
+            private translate: TranslateService, private network: Network, private zone: NgZone) {
         this.logger = logger.getInstance('CoreUtilsProvider');
     }
 
+    /**
+     * Check if a frame uses an online URL but the app is offline. If it does, the iframe is hidden and a warning is shown.
+     *
+     * @param {any} element The frame to check (iframe, embed, ...).
+     * @param {boolean} [isSubframe] Whether it's a frame inside another frame.
+     * @return {boolean} True if frame is online and the app is offline, false otherwise.
+     */
+    checkOnlineFrameInOffline(element: any, isSubframe?: boolean): boolean {
+        const src = element.src || element.data;
+
+        if (src && src.match(/^https?:\/\//i) && !this.appProvider.isOnline()) {
+            if (element.classList.contains('core-iframe-offline-disabled')) {
+                // Iframe already hidden, stop.
+                return true;
+            }
+
+            // The frame has an online URL but the app is offline. Show a warning.
+            const div = document.createElement('div');
+
+            div.setAttribute('text-center', '');
+            div.setAttribute('padding', '');
+            div.classList.add('core-iframe-offline-warning');
+            div.innerHTML = (isSubframe ?  '' : this.domUtils.getConnectionWarningIconHtml()) +
+                    '<p>' + this.translate.instant('core.networkerroriframemsg') + '</p>';
+
+            element.parentElement.insertBefore(div, element);
+
+            // Add a class to specify that the iframe is hidden.
+            element.classList.add('core-iframe-offline-disabled');
+
+            if (isSubframe) {
+                // We cannot apply CSS styles in subframes, just hide the iframe.
+                element.style.display = 'none';
+            }
+
+            // If the network changes, check it again.
+            const subscription = this.network.onConnect().subscribe(() => {
+                // Execute the callback in the Angular zone, so change detection doesn't stop working.
+                this.zone.run(() => {
+                    if (!this.checkOnlineFrameInOffline(element, isSubframe)) {
+                        // Now the app is online, no need to check connection again.
+                        subscription.unsubscribe();
+                    }
+                });
+            });
+
+            return true;
+        } else if (element.classList.contains('core-iframe-offline-disabled')) {
+            // Reload the frame.
+            element.src = element.src;
+            element.data = element.data;
+
+            // Remove the warning and show the iframe
+            this.domUtils.removeElement(element.parentElement, 'div.core-iframe-offline-warning');
+            element.classList.remove('core-iframe-offline-disabled');
+
+            if (isSubframe) {
+                element.style.display = '';
+            }
+        }
+
+        return false;
+    }
+
     /**
      * Given an element, return the content window and document.
      * Please notice that the element should be an iframe, embed or similar.
@@ -136,7 +204,7 @@ export class CoreIframeUtilsProvider {
             CoreIframeUtilsProvider.FRAME_TAGS.forEach((tag) => {
                 const elements = Array.from(contentDocument.querySelectorAll(tag));
                 elements.forEach((subElement) => {
-                    this.treatFrame(subElement);
+                    this.treatFrame(subElement, true);
                 });
             });
         }
@@ -147,9 +215,12 @@ export class CoreIframeUtilsProvider {
      * Search links (<a>) and open them in browser or InAppBrowser if needed.
      *
      * @param {any} element Element to treat (iframe, embed, ...).
+     * @param {boolean} [isSubframe] Whether it's a frame inside another frame.
      */
-    treatFrame(element: any): void {
+    treatFrame(element: any, isSubframe?: boolean): void {
         if (element) {
+            this.checkOnlineFrameInOffline(element, isSubframe);
+
             let winAndDoc = this.getContentWindowAndDocument(element);
             // Redefine window.open in this element and sub frames, it might have been loaded already.
             this.redefineWindowOpen(element, winAndDoc.window, winAndDoc.document);
@@ -157,6 +228,8 @@ export class CoreIframeUtilsProvider {
             this.treatFrameLinks(element, winAndDoc.document);
 
             element.addEventListener('load', () => {
+                this.checkOnlineFrameInOffline(element, isSubframe);
+
                 // Element loaded, redefine window.open and treat links again.
                 winAndDoc = this.getContentWindowAndDocument(element);
                 this.redefineWindowOpen(element, winAndDoc.window, winAndDoc.document);