Enqueue requests made from QuickIcon plugins

build/media_source/com_cpanel/js/admin-system-loader.es6.js

@@ -20,6 +20,7 @@
           Joomla.request({
             url: badgeurl,
             method: 'POST',
+            queued: true,
             onSuccess: (resp) => {
               let response;
               try {

build/media_source/plg_quickicon_extensionupdate/js/extensionupdatecheck.es6.js

@@ -25,11 +25,17 @@
         }
       };
 
+      /**
+       * DO NOT use fetch() for QuickIcon requests. They must be queued.
+       *
+       * @see https://github.com/joomla/joomla-cms/issues/38001
+       */
       Joomla.request({
         url: options.ajaxUrl,
         method: 'GET',
         data: '',
         perform: true,
+        queued: true,
         onSuccess: (response) => {
           const updateInfoList = JSON.parse(response);
 

build/media_source/plg_quickicon_joomlaupdate/js/jupdatecheck.es6.js

@@ -21,36 +21,43 @@ if (Joomla && Joomla.getOptions('js-extensions-update')) {
   const fetchUpdate = () => {
     const options = Joomla.getOptions('js-joomla-update');
 
-    fetch(options.ajaxUrl, { method: 'GET' })
-      .then((response) => {
-        response.json().then((updateInfoList) => {
-          if (Array.isArray(updateInfoList)) {
-            if (updateInfoList.length === 0) {
-              // No updates
-              update('success', Joomla.Text._('PLG_QUICKICON_JOOMLAUPDATE_UPTODATE'));
-            } else {
-              const updateInfo = updateInfoList.shift();
+    /**
+     * DO NOT use fetch() for QuickIcon requests. They must be queued.
+     *
+     * @see https://github.com/joomla/joomla-cms/issues/38001
+     */
+    Joomla.request({
+      url: options.ajaxUrl,
+      method: 'GET',
+      data: '',
+      perform: true,
+      queued: true,
+      onSuccess: (response) => {
+        const updateInfoList = JSON.parse(response);
 
-              if (updateInfo.version !== options.version) {
-                update('danger', Joomla.Text._('PLG_QUICKICON_JOOMLAUPDATE_UPDATEFOUND').replace('%s', `<span class="badge text-dark bg-light"> \u200E ${updateInfo.version}</span>`));
-              } else {
-                update('success', Joomla.Text._('PLG_QUICKICON_JOOMLAUPDATE_UPTODATE'));
-              }
-            }
+        if (Array.isArray(updateInfoList)) {
+          if (updateInfoList.length === 0) {
+            // No updates
+            update('success', Joomla.Text._('PLG_QUICKICON_JOOMLAUPDATE_UPTODATE'));
           } else {
-            // An error occurred
-            update('danger', Joomla.Text._('PLG_QUICKICON_JOOMLAUPDATE_ERROR'));
+            const updateInfo = updateInfoList.shift();
+
+            if (updateInfo.version !== options.version) {
+              update('danger', Joomla.Text._('PLG_QUICKICON_JOOMLAUPDATE_UPDATEFOUND').replace('%s', `<span class="badge text-dark bg-light"> \u200E ${updateInfo.version}</span>`));
+            } else {
+              update('success', Joomla.Text._('PLG_QUICKICON_JOOMLAUPDATE_UPTODATE'));
+            }
           }
-        })
-          .catch(() => {
-            // An error occurred
-            update('danger', Joomla.Text._('PLG_QUICKICON_JOOMLAUPDATE_ERROR'));
-          });
-      })
-      .catch(() => {
+        } else {
+          // An error occurred
+          update('danger', Joomla.Text._('PLG_QUICKICON_JOOMLAUPDATE_ERROR'));
+        }
+      },
+      onError: () => {
         // An error occurred
         update('danger', Joomla.Text._('PLG_QUICKICON_JOOMLAUPDATE_ERROR'));
-      });
+      },
+    });
   };
 
   // Give some times to the layout and other scripts to settle their stuff

build/media_source/plg_quickicon_overridecheck/js/overridecheck.es6.js

@@ -28,11 +28,17 @@
         }
       };
 
+      /**
+       * DO NOT use fetch() for QuickIcon requests. They must be queued.
+       *
+       * @see https://github.com/joomla/joomla-cms/issues/38001
+       */
       Joomla.request({
         url: options.ajaxUrl,
         method: 'GET',
         data: '',
         perform: true,
+        queued: true,
         onSuccess: (response) => {
           const updateInfoList = JSON.parse(response);
 

build/media_source/plg_quickicon_privacycheck/js/privacycheck.es6.js

@@ -14,11 +14,17 @@
     const quickicon = document.getElementById('plg_quickicon_privacycheck');
     const link = quickicon.querySelector('span.j-links-link');
 
+    /**
+     * DO NOT use fetch() for QuickIcon requests. They must be queued.
+     *
+     * @see https://github.com/joomla/joomla-cms/issues/38001
+     */
     Joomla.request({
       url: ajaxUrl,
       method: 'GET',
       data: '',
       perform: true,
+      queued: true,
       onSuccess: (response) => {
         try {
           const request = JSON.parse(response);

build/media_source/system/js/core.es6.js

@@ -565,6 +565,27 @@ window.Joomla.Modal = window.Joomla.Modal || {
     });
   };
 
+  /**
+   * Joomla Request queue.
+   *
+   * A FIFO queue of requests to execute serially. Used to prevent simultaneous execution of
+   * multiple requests against the server which could trigger its Denial of Service protection.
+   *
+   * @type  {Array}
+   *
+   * @since __DEPLOY_VERSION__
+   */
+  const requestQueue = [];
+
+  /**
+   * Flag to indicate whether Joomla is performing a queued Request.
+   *
+   * @type  {boolean}
+   *
+   * @since __DEPLOY_VERSION__
+   */
+  let performingQueuedRequest = false;
+
   /**
    * Method to perform AJAX request
    *
@@ -576,6 +597,8 @@ window.Joomla.Modal = window.Joomla.Modal || {
    *                https://developer.mozilla.org/docs/Web/API/XMLHttpRequest/send
    *    perform: true,        Perform the request immediately
    *              or return XMLHttpRequest instance and perform it later
+   *    queued: false,        Put the request in a FIFO queue; prevents simultaneous execution of
+   *              multiple requests to avoid triggering the server's Denial of Service protection.
    *    headers: null,        Object of custom headers, eg {'X-Foo': 'Bar', 'X-Bar': 'Foo'}
    *
    *    onBefore:  (xhr) => {}            // Callback on before the request
@@ -598,13 +621,32 @@ window.Joomla.Modal = window.Joomla.Modal || {
    * @see    https://developer.mozilla.org/docs/Web/API/XMLHttpRequest
    */
   Joomla.request = (options) => {
+    /**
+     * Processes queued Request objects.
+     *
+     * @since __DEPLOY_VERSION__
+     */
+    const processQueuedRequests = () => {
+      if (performingQueuedRequest || requestQueue.length === 0) {
+        return;
+      }
+
+      performingQueuedRequest = true;
+
+      const nextRequest = requestQueue.shift();
+
+      nextRequest.xhr.send(nextRequest.data);
+    };
+
     let xhr;
+
     // Prepare the options
     const newOptions = Joomla.extend({
       url: '',
       method: 'GET',
       data: null,
       perform: true,
+      queued: false,
     }, options);
 
     // Set up XMLHttpRequest instance
@@ -648,6 +690,12 @@ window.Joomla.Modal = window.Joomla.Modal || {
           return;
         }
 
+        // The request is finished; step through any more queued requests
+        if (newOptions.queued) {
+          performingQueuedRequest = false;
+          processQueuedRequests();
+        }
+
         // Request finished and response is ready
         if (xhr.status === 200) {
           if (newOptions.onSuccess) {
@@ -663,14 +711,23 @@ window.Joomla.Modal = window.Joomla.Modal || {
       };
 
       // Do request
-      if (newOptions.perform) {
+      if (newOptions.perform && !newOptions.queued) {
         if (newOptions.onBefore && newOptions.onBefore.call(window, xhr) === false) {
           // Request interrupted
           return xhr;
         }
 
         xhr.send(newOptions.data);
       }
+
+      // Enqueue request and try to process the queue
+      if (newOptions.queued) {
+        requestQueue.push({
+          xhr,
+          data: newOptions.data,
+        });
+        processQueuedRequests();
+      }
     } catch (error) {
       // eslint-disable-next-line no-unused-expressions,no-console
       window.console ? console.log(error) : null;