Implement idea suggested in ScratchAddons#6665

addons/faster-project-loading/module.js

@@ -0,0 +1,25 @@
+
+
+export const BACKPACK_URL = "https://backpack.scratch.mit.edu/";
+
+// Inserting sprites from the backpack requests a ZIP archive from backpack.scratch.mit.edu, so we want to allow those
+export const SPRITE_FILE_EXTENSION = ".zip";
+
+
+/**
+ * Returns true if a web worker request is being caused by the Scratch bug
+ * https://github.com/scratchfoundation/scratch-gui/issues/8805.
+ * @param {*} message The message being sent to the web worker.
+ * @returns {boolean}
+ */
+export function isBadRequest(message) {
+  if (!message) return false;
+
+  if (typeof message.id !== "string" || typeof message.url !== "string") return false;
+
+  if (!message.url.startsWith(BACKPACK_URL)) return false;
+
+  if (message.url.endsWith(SPRITE_FILE_EXTENSION)) return false;
+
+  return true;
+}

addons/faster-project-loading/userscript.js

@@ -1,13 +1,12 @@
 // This is a fix for https://github.com/scratchfoundation/scratch-gui/issues/8805
 
+import { BACKPACK_URL, SPRITE_FILE_EXTENSION, isBadRequest } from './module.js'
+
 export default async function ({ addon }) {
-  const BACKPACK_URL = "https://backpack.scratch.mit.edu/";
-  // Inserting sprites from the backpack requests a ZIP archive from backpack.scratch.mit.edu, so we want to allow those
-  const SPRITE_FILE_EXTENSION = ".zip";
   // Dropping a code item from the backpack into a specific sprite within the sprite-pane (NOT into the code area)
   // requests a JSON file (https://backpack.scratch.mit.edu/{hash}.json) which we shouldn't block
   const CODE_FILE_EXTENSION = ".json";
-
+  await new Promise(r => setTimeout(r, 100));
   const originalOpen = XMLHttpRequest.prototype.open;
   XMLHttpRequest.prototype.open = function (method, url, ...moreArgs) {
     if (
@@ -31,10 +30,8 @@ export default async function ({ addon }) {
 
   const originalPostMessage = Worker.prototype.postMessage;
   Worker.prototype.postMessage = function (message, options, ...moreArgs) {
-    if (!addon.self.disabled && message && typeof message.id === "string" && typeof message.url === "string") {
-      if (message.url.startsWith(BACKPACK_URL) && !message.url.endsWith(SPRITE_FILE_EXTENSION)) {
-        throw new Error("Request blocked by Scratch Addons faster project loading.");
-      }
+    if (!addon.self.disabled && isBadRequest(message)) {
+      throw new Error("Request blocked by Scratch Addons faster project loading.");
     }
     originalPostMessage.call(this, message, options, ...moreArgs);
   };

addons/progress-bar/userscript.js

@@ -1,3 +1,6 @@
+
+import { isBadRequest } from '../faster-project-loading/module.js'
+
 export default async function ({ addon, console, msg }) {
   const useTopBar = addon.settings.get("topbar");
 
@@ -34,6 +37,9 @@ export default async function ({ addon, console, msg }) {
 
   let resetTimeout;
 
+  // A boolean indicating if the bug scratch-gui#8805 has happened.
+  let hasBadRequests = false;
+
   function setProgress(progress) {
     if (progress < 0) progress = 0;
     if (progress > 1) progress = 1;
@@ -74,6 +80,7 @@ export default async function ({ addon, console, msg }) {
     startObserver();
     totalTasks = 0;
     finishedTasks = 0;
+    hasBadRequests = false;
   }
 
   function updateTasks() {
@@ -173,24 +180,37 @@ export default async function ({ addon, console, msg }) {
   // Scratch uses a Worker to fetch project assets.
   // As the worker may be constructed before we run, we have to patch postMessage to monitor message passing.
   let foundWorker = false;
+
   const originalPostMessage = Worker.prototype.postMessage;
   Worker.prototype.postMessage = function (message, options) {
     if (!addon.self.disabled && message && typeof message.id === "string" && typeof message.url === "string") {
       // This is a message passed to the worker to start an asset download.
       setLoadingPhase(LOAD_ASSETS);
-      totalTasks++;
-      updateTasks();
-
-      // Add our own message handler once for this worker to monitor when assets have finished loading.
-      if (!foundWorker) {
-        foundWorker = true;
-        this.addEventListener("message", (e) => {
-          const data = e.data;
-          if (Array.isArray(data)) {
-            finishedTasks += data.length;
-            updateTasks();
-          }
-        });
+
+      function addTask() {
+        ++totalTasks;
+        updateTasks();
+      }
+
+      if (isBadRequest(message)) {
+        addTask();
+        hasBadRequests |= true;
+      } else {
+        // Only add the task if a bad request hasn't already added it
+        if (!hasBadRequests)
+          addTask();
+
+        // Add our own message handler once for this worker to monitor when assets have finished loading.
+        if (!foundWorker) {
+          foundWorker = true;
+          this.addEventListener("message", (e) => {
+            const data = e.data;
+            if (Array.isArray(data)) {
+              finishedTasks += data.length;
+              updateTasks();
+            }
+          });
+        }
       }
     }