Simplify messaging logic and add acknowledgement

kiwix · Nov 16, 2023 · 9572170 · 9572170
1 parent 1586290
commit 9572170
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Showing 2 changed files with 32 additions and 20 deletions.
diff --git a/service-worker.js b/service-worker.js
@@ -290,6 +290,12 @@ self.addEventListener('message', function (event) {
         if (event.data.action === 'init') {
             // On 'init' message, we enable the fetchEventListener
             fetchCaptureEnabled = true;
+            // Acdknowledge the init message to all clients
+            self.clients.matchAll().then(function (clientList) {
+                clientList.forEach(function (client) {
+                    client.postMessage({ action: 'acknowledge' });
+                });
+            });
         } else if (event.data.action === 'disable') {
             // On 'disable' message, we disable the fetchEventListener
             // Note that this code doesn't currently run because the app currently never sends a 'disable' message

diff --git a/www/js/app.js b/www/js/app.js
@@ -795,47 +795,55 @@ function initServiceWorkerMessaging () {
     if (params.contentInjectionMode === 'serviceworker') {
         // Create a message listener
         navigator.serviceWorker.onmessage = function (event) {
-            if (!selectedArchive) {
-                console.warn('Message from SW received, but no archive is selected!');
-                return;
-            }
             if (event.data.error) {
                 console.error('Error in MessageChannel', event.data.error);
                 throw event.data.error;
-            }
-            if (event.data.action === 'askForContent') {
+            } else if (event.data.action === 'acknowledge') {
+                // The Service Worker is acknowledging receipt of init message
+                console.log('SW acknowledged init message');
+                initServiceWorkerHandle = true;
+            } else if (event.data.action === 'askForContent') {
+                // The Service Worker is asking for content. Check we have a loaded ZIM in this instance.
+                // DEV: This can happen if there are various instances of the app open in different tabs or windows, and no archive has been selected in this instance.
+                if (!selectedArchive) {
+                    console.warn('Message from SW received, but no archive is selected!');
+                    return;
+                }
+                // See below for explanation of this exception
+                const videoException = selectedArchive.zimType === 'zimit' && /\/\/youtubei.*player/.test(event.data.title);
                 // Check that the zimFileId in the messageChannel event data is the same as the one in the currently open archive
                 // Because the SW broadcasts its request to all open tabs or windows, we need to check that the request is for this instance
-                if (event.data.zimFileName !== selectedArchive.file.name) {
-                    console.warn('SW request does not match this insstance', '[zimFileName:' + event.data.zimFileName + ' !== ' + selectedArchive.file.name + ']');
-                    if (selectedArchive.zimType === 'zimit' && /\/\/youtubei.*player/.test(event.data.title)) {
+                if (event.data.zimFileName !== selectedArchive.file.name && !videoException) {
+                    // Do nothing if the request is not for this instance
+                    // console.debug('SW request does not match this instance', '[zimFileName:' + event.data.zimFileName + ' !== ' + selectedArchive.file.name + ']');
+                } else {
+                    if (videoException) {
                         // DEV: This is a hack to allow YouTube videos to play in Zimit archives:
                         // Because links are embedded in a nested iframe, the SW cannot identify the top-level window from which to request the ZIM content
-                        // Until we find a way to tell where it is coming from, we allow the request through and try to load the content
-                        console.warn('>>> Allowing passthrough to process YouTube video <<<');
-                    } else {
-                        return;
+                        // Until we find a way to tell where it is coming from, we allow the request through on all controlled clients and try to load the content
+                        console.warn('>>> Allowing passthrough of SW request to process Zimit video <<<');
                     }
+                    handleMessageChannelMessage(event);
                 }
-                handleMessageChannelMessage(event)
             } else {
                 console.error('Invalid message received', event.data);
             }
         };
         // Send the init message to the ServiceWorker
         if (navigator.serviceWorker.controller) {
+            console.log('Initializing SW messaging...');
             navigator.serviceWorker.controller.postMessage({
                 action: 'init'
             });
-        } else if (initServiceWorkerHandle) {
+        } else if (!initServiceWorkerHandle) {
             console.error('The Service Worker is active but is not controlling the current page! We have to reload.');
             // Turn off failsafe, as this is a controlled reboot
             settingsStore.setItem('lastPageLoad', 'rebooting', Infinity);
             window.location.reload();
         } else {
             // If this is the first time we are initiating the SW, allow Promises to complete by delaying potential reload till next tick
             console.debug('The Service Worker needs more time to load...');
-            initServiceWorkerHandle = setTimeout(initServiceWorkerMessaging, 0);
+            setTimeout(initServiceWorkerMessaging, 0);
         }
     }
 }
@@ -1293,10 +1301,8 @@ function setLocalArchiveFromArchiveList () {
  * Resets the CSS Cache (used only in jQuery mode)
  */
 function resetCssCache () {
-    // Reset the cssCache. Must be done when archive changes.
-    if (selectedArchive.cssCache) {
-        selectedArchive.cssCache = new Map();
-    }
+    // Reset the cssCache if an archive is loaded
+    if (selectedArchive) selectedArchive.cssCache = new Map();
 }
 
 let webKitFileList = null