Add a setting to retrieve bookmark metadata asynchrounously

  - There is a new standalone script (metadata.js) which requests
    a new controller to get bookmark metadata and fill the form async
  - This feature is enabled with the new setting: general.enable_async_metadata
    (enabled by default)
  - general.retrieve_description is now enabled by default
  - A small rotating loader animation has a been added to bookmark inputs
    when metadata is being retrieved (default template)
  - Custom JS htmlentities has been removed and  mathiasbynens/he
    library is used instead

Fixes #1563

3 files changed, 92 insertions, 10 deletions

diff --git a/assets/common/js/metadata.js b/assets/common/js/metadata.js
new file mode 100644
index 00000000..5200b481
--- /dev/null
+++ b/assets/common/js/metadata.js
@@ -0,0 +1,39 @@
+import he from 'he';
+
+function clearLoaders(loaders) {
+  if (loaders != null && loaders.length > 0) {
+    [...loaders].forEach((loader) => {
+      loader.classList.remove('loading-input');
+    });
+  }
+}
+
+(() => {
+  const loaders = document.querySelectorAll('.loading-input');
+  const inputTitle = document.querySelector('input[name="lf_title"]');
+  if (inputTitle != null && inputTitle.value.length > 0) {
+    clearLoaders(loaders);
+    return;
+  }
+
+  const url = document.querySelector('input[name="lf_url"]').value;
+  const basePath = document.querySelector('input[name="js_base_path"]').value;
+
+  const xhr = new XMLHttpRequest();
+  xhr.open('GET', `${basePath}/admin/metadata?url=${encodeURI(url)}`, true);
+  xhr.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');
+  xhr.onload = () => {
+    const result = JSON.parse(xhr.response);
+    Object.keys(result).forEach((key) => {
+      if (result[key] !== null && result[key].length) {
+        const element = document.querySelector(`input[name="lf_${key}"], textarea[name="lf_${key}"]`);
+        if (element != null && element.value.length === 0) {
+          element.value = he.decode(result[key]);
+        }
+      }
+    });
+    clearLoaders(loaders);
+  };
+
+  xhr.send();
+})();
diff --git a/assets/default/js/base.js b/assets/default/js/base.js
index be986ae0..31688815 100644
--- a/assets/default/js/base.js
+++ b/assets/default/js/base.js
@@ -1,4 +1,5 @@
 import Awesomplete from 'awesomplete';
+import he from 'he';
 
 /**
  * Find a parent element according to its tag and its attributes
@@ -96,15 +97,6 @@ function updateAwesompleteList(selector, tags, instances) {
 }
 
 /**
- * html_entities in JS
- *
- * @see http://stackoverflow.com/questions/18749591/encode-html-entities-in-javascript
- */
-function htmlEntities(str) {
-  return str.replace(/[\u00A0-\u9999<>&]/gim, (i) => `&#${i.charCodeAt(0)};`);
-}
-
-/**
  * Add the class 'hidden' to city options not attached to the current selected continent.
  *
  * @param cities           List of <option> elements
@@ -569,7 +561,7 @@ function init(description) {
           input.setAttribute('name', totag);
           input.setAttribute('value', totag);
           findParent(input, 'div', { class: 'rename-tag-form' }).style.display = 'none';
-          block.querySelector('a.tag-link').innerHTML = htmlEntities(totag);
+          block.querySelector('a.tag-link').innerHTML = he.encode(totag);
           block
             .querySelector('a.tag-link')
             .setAttribute('href', `${basePath}/?searchtags=${encodeURIComponent(totag)}`);
diff --git a/assets/default/scss/shaarli.scss b/assets/default/scss/shaarli.scss
index a528adb0..df9c867b 100644
--- a/assets/default/scss/shaarli.scss
+++ b/assets/default/scss/shaarli.scss
@@ -1269,6 +1269,57 @@ form {
   }
 }
 
+.loading-input {
+  position: relative;
+
+  @keyframes around {
+    0% {
+      transform: rotate(0deg);
+    }
+
+    100% {
+      transform: rotate(360deg);
+    }
+  }
+
+  .icon-container {
+    position: absolute;
+    right: 60px;
+    top: calc(50% - 10px);
+  }
+
+  .loader {
+    position: relative;
+    height: 20px;
+    width: 20px;
+    display: inline-block;
+    animation: around 5.4s infinite;
+
+    &::after,
+    &::before {
+      content: "";
+      background: $form-input-background;
+      position: absolute;
+      display: inline-block;
+      width: 100%;
+      height: 100%;
+      border-width: 2px;
+      border-color: #333 #333 transparent transparent;
+      border-style: solid;
+      border-radius: 20px;
+      box-sizing: border-box;
+      top: 0;
+      left: 0;
+      animation: around 0.7s ease-in-out infinite;
+    }
+
+    &::after {
+      animation: around 0.7s ease-in-out 0.1s infinite;
+      background: transparent;
+    }
+  }
+}
+
 // LOGIN
 .login-form-container {
   .remember-me {