Add a page to update all thumbnails through AJAX requests in both templates

assets/common/js/thumbnails-update.js

@@ -0,0 +1,51 @@
+/**
+ * Script used in the thumbnails update page.
+ *
+ * It retrieves the list of link IDs to update, and execute AJAX requests
+ * to update their thumbnails, while updating the progress bar.
+ */
+
+/**
+ * Update the thumbnail of the link with the current i index in ids.
+ * It contains a recursive call to retrieve the thumb of the next link when it succeed.
+ * It also update the progress bar and other visual feedback elements.
+ *
+ * @param {array}  ids      List of LinkID to update
+ * @param {int}    i        Current index in ids
+ * @param {object} elements List of DOM element to avoid retrieving them at each iteration
+ */
+function updateThumb(ids, i, elements) {
+  const xhr = new XMLHttpRequest();
+  xhr.open('POST', '?do=ajax_thumb_update');
+  xhr.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');
+  xhr.responseType = 'json';
+  xhr.onload = () => {
+    if (xhr.status !== 200) {
+      alert(`An error occurred. Return code: ${xhr.status}`);
+    } else {
+      const { response } = xhr;
+      i += 1;
+      elements.progressBar.style.width = `${(i * 100) / ids.length}%`;
+      elements.current.innerHTML = i;
+      elements.title.innerHTML = response.title;
+      if (response.thumbnail !== false) {
+        elements.thumbnail.innerHTML = `<img src="${response.thumbnail}">`;
+      }
+      if (i < ids.length) {
+        updateThumb(ids, i, elements);
+      }
+    }
+  };
+  xhr.send(`id=${ids[i]}`);
+}
+
+(() => {
+  const ids = document.getElementsByName('ids')[0].value.split(',');
+  const elements = {
+    progressBar: document.querySelector('.progressbar > div'),
+    current: document.querySelector('.progress-current'),
+    thumbnail: document.querySelector('.thumbnail-placeholder'),
+    title: document.querySelector('.thumbnail-link-title'),
+  };
+  updateThumb(ids, 0, elements);
+})();