From a266ba6e62995afe451cdda0a2d7b68b5bdc3cb9 Mon Sep 17 00:00:00 2001
From: Alex Pott <alex.a.pott@googlemail.com>
Date: Wed, 30 Nov 2022 16:33:11 +0000
Subject: [PATCH] Issue #3247795 by heddn, Graber, ravi.shankar, yogeshmpawar,
 Anchal_gupta, Wim Leers, Fabianx, alexpott, benmorss, catch: Add text filter
 plugin to support <img loading="lazy"> and remove it from
 editor_file_reference

---
 .../FunctionalJavascript/CKEditor5Test.php    |  4 +-
 core/modules/editor/editor.post_update.php    | 31 +++++++
 .../src/Plugin/Filter/EditorFileReference.php | 22 ++---
 ...EditorAddLazyLoadImageFilterUpdateTest.php | 48 +++++++++++
 .../Kernel/EditorFileReferenceFilterTest.php  | 12 +--
 .../src/Plugin/Filter/FilterImageLazyLoad.php | 59 +++++++++++++
 .../src/Unit/FilterImageLazyLoadTest.php      | 86 +++++++++++++++++++
 .../install/filter.format.basic_html.yml      |  8 +-
 .../install/filter.format.full_html.yml       |  6 ++
 .../install/filter.format.basic_html.yml      |  6 ++
 .../install/filter.format.full_html.yml       |  6 ++
 11 files changed, 265 insertions(+), 23 deletions(-)
 create mode 100644 core/modules/editor/tests/src/Functional/Update/EditorAddLazyLoadImageFilterUpdateTest.php
 create mode 100644 core/modules/filter/src/Plugin/Filter/FilterImageLazyLoad.php
 create mode 100644 core/modules/filter/tests/src/Unit/FilterImageLazyLoadTest.php

diff --git a/core/modules/ckeditor5/tests/src/FunctionalJavascript/CKEditor5Test.php b/core/modules/ckeditor5/tests/src/FunctionalJavascript/CKEditor5Test.php
index 76c40a2ce21..61b337f1fb6 100644
--- a/core/modules/ckeditor5/tests/src/FunctionalJavascript/CKEditor5Test.php
+++ b/core/modules/ckeditor5/tests/src/FunctionalJavascript/CKEditor5Test.php
@@ -543,7 +543,7 @@ JS;
     $uploaded_image = File::load(1);
     $image_url = $this->container->get('file_url_generator')->generateString($uploaded_image->getFileUri());
     $image_uuid = $uploaded_image->uuid();
-    $assert_session->elementExists('xpath', sprintf('//img[@src="%s" and @loading="lazy" and @width and @height and @data-entity-uuid="%s" and @data-entity-type="file"]', $image_url, $image_uuid));
+    $assert_session->elementExists('xpath', sprintf('//img[@src="%s" and @width and @height and @data-entity-uuid="%s" and @data-entity-type="file"]', $image_url, $image_uuid));
 
     // Ensure that width, height, and length attributes are not stored in the
     // database.
@@ -555,7 +555,7 @@ JS;
     $this->assertNotEmpty($assert_session->waitForElement('css', '.ck-editor'));
     $page->pressButton('Save');
 
-    $assert_session->elementExists('xpath', sprintf('//img[@src="%s" and @loading="lazy" and @width and @height and @data-entity-uuid="%s" and @data-entity-type="file"]', $image_url, $image_uuid));
+    $assert_session->elementExists('xpath', sprintf('//img[@src="%s" and @width and @height and @data-entity-uuid="%s" and @data-entity-type="file"]', $image_url, $image_uuid));
   }
 
   /**
diff --git a/core/modules/editor/editor.post_update.php b/core/modules/editor/editor.post_update.php
index 71814f3101f..112409ecb0e 100644
--- a/core/modules/editor/editor.post_update.php
+++ b/core/modules/editor/editor.post_update.php
@@ -5,6 +5,10 @@
  * Post update functions for Editor.
  */
 
+use Drupal\filter\Entity\FilterFormat;
+use Drupal\filter\FilterFormatInterface;
+use Drupal\filter\FilterPluginCollection;
+
 /**
  * Implements hook_removed_post_updates().
  */
@@ -13,3 +17,30 @@ function editor_removed_post_updates() {
     'editor_post_update_clear_cache_for_file_reference_filter' => '9.0.0',
   ];
 }
+
+/**
+ * Enable filter_image_lazy_load if editor_file_reference is enabled.
+ */
+function editor_post_update_image_lazy_load(): void {
+  if (\Drupal::service('plugin.manager.filter')->hasDefinition('editor_file_reference')) {
+    foreach (FilterFormat::loadMultiple() as $format) {
+      assert($format instanceof FilterFormatInterface);
+      $collection = $format->filters();
+      $configuration = $collection->getConfiguration();
+      assert($collection instanceof FilterPluginCollection);
+      if (array_key_exists('editor_file_reference', $configuration)) {
+        $collection->addInstanceId('filter_image_lazy_load');
+        $configuration['filter_image_lazy_load'] = [
+          'id' => 'filter_image_lazy_load',
+          'provider' => 'editor',
+          'status' => TRUE,
+          // Place lazy loading after editor file reference.
+          'weight' => $configuration['editor_file_reference']['weight'] + 1,
+          'settings' => [],
+        ];
+        $collection->setConfiguration($configuration);
+        $format->save();
+      }
+    }
+  }
+}
diff --git a/core/modules/editor/src/Plugin/Filter/EditorFileReference.php b/core/modules/editor/src/Plugin/Filter/EditorFileReference.php
index e41901f7c41..d107b95347b 100644
--- a/core/modules/editor/src/Plugin/Filter/EditorFileReference.php
+++ b/core/modules/editor/src/Plugin/Filter/EditorFileReference.php
@@ -19,7 +19,7 @@ use Symfony\Component\DependencyInjection\ContainerInterface;
  * @Filter(
  *   id = "editor_file_reference",
  *   title = @Translation("Track images uploaded via a Text Editor"),
- *   description = @Translation("Ensures that the latest versions of images uploaded via a Text Editor are displayed."),
+ *   description = @Translation("Ensures that the latest versions of images uploaded via a Text Editor are displayed, along with their dimensions."),
  *   type = Drupal\filter\Plugin\FilterInterface::TYPE_TRANSFORM_REVERSIBLE
  * )
  */
@@ -92,22 +92,16 @@ class EditorFileReference extends FilterBase implements ContainerFactoryPluginIn
           if ($file instanceof FileInterface) {
             $node->setAttribute('src', $file->createFileUrl());
             if ($node->nodeName == 'img') {
-              // Without dimensions specified, layout shifts can occur,
-              // which are more noticeable on pages that take some time to load.
-              // As a result, only mark images as lazy load that have dimensions.
               $image = $this->imageFactory->get($file->getFileUri());
               $width = $image->getWidth();
               $height = $image->getHeight();
-              if ($width !== NULL && $height !== NULL) {
-                if (!$node->hasAttribute('width')) {
-                  $node->setAttribute('width', $width);
-                }
-                if (!$node->hasAttribute('height')) {
-                  $node->setAttribute('height', $height);
-                }
-                if (!$node->hasAttribute('loading')) {
-                  $node->setAttribute('loading', 'lazy');
-                }
+              // Set dimensions to avoid content layout shift (CLS).
+              // @see https://web.dev/cls/
+              if ($width !== NULL && !$node->hasAttribute('width')) {
+                $node->setAttribute('width', (string) $width);
+              }
+              if ($height !== NULL && !$node->hasAttribute('height')) {
+                $node->setAttribute('height', (string) $height);
               }
             }
           }
diff --git a/core/modules/editor/tests/src/Functional/Update/EditorAddLazyLoadImageFilterUpdateTest.php b/core/modules/editor/tests/src/Functional/Update/EditorAddLazyLoadImageFilterUpdateTest.php
new file mode 100644
index 00000000000..a4e9b659b15
--- /dev/null
+++ b/core/modules/editor/tests/src/Functional/Update/EditorAddLazyLoadImageFilterUpdateTest.php
@@ -0,0 +1,48 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\Tests\editor\Functional\Update;
+
+use Drupal\FunctionalTests\Update\UpdatePathTestBase;
+
+/**
+ * Tests automatically adding editor_image_lazy_load filter to text formats
+ * using editor_file_reference.
+ *
+ * @group Update
+ */
+class EditorAddLazyLoadImageFilterUpdateTest extends UpdatePathTestBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  protected $defaultTheme = 'stark';
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function setDatabaseDumpFiles(): void {
+    $this->databaseDumpFiles = [
+      __DIR__ . '/../../../../../system/tests/fixtures/update/drupal-9.4.0.bare.standard.php.gz',
+    ];
+  }
+
+  /**
+   * Tests upgrading filter settings.
+   *
+   * @see editor_post_update_image_lazy_load()
+   */
+  public function testUpdateLazyImageLoad(): void {
+    $config = $this->config('filter.format.full_html');
+    $this->assertArrayNotHasKey('filter_image_lazy_load', $config->get('filters'));
+
+    $this->runUpdates();
+
+    $config = $this->config('filter.format.full_html');
+    $filters = $config->get('filters');
+    $this->assertArrayHasKey('filter_image_lazy_load', $filters);
+    $this->assertEquals($filters['editor_file_reference']['weight'] + 1, $filters['filter_image_lazy_load']['weight']);
+  }
+
+}
diff --git a/core/modules/editor/tests/src/Kernel/EditorFileReferenceFilterTest.php b/core/modules/editor/tests/src/Kernel/EditorFileReferenceFilterTest.php
index 19877a6fa93..b764eedaef8 100644
--- a/core/modules/editor/tests/src/Kernel/EditorFileReferenceFilterTest.php
+++ b/core/modules/editor/tests/src/Kernel/EditorFileReferenceFilterTest.php
@@ -130,7 +130,7 @@ class EditorFileReferenceFilterTest extends KernelTestBase {
     $this->assertSame($expected_output, $output->getProcessedText());
     $this->assertEquals($cache_tag, $output->getCacheTags());
 
-    // Add a valid image for test lazy loading feature.
+    // Add a valid image for image dimension testing.
     /** @var array stdClass */
     $files = $this->getTestFiles('image');
     $image = reset($files);
@@ -138,16 +138,16 @@ class EditorFileReferenceFilterTest extends KernelTestBase {
     [$width, $height] = getimagesize('public://llama.jpg');
     $dimensions = 'width="' . $width . '" height="' . $height . '"';
 
-    // Image dimensions and loading attributes are present.
+    // Image dimensions are present.
     $input = '<img src="llama.jpg" data-entity-type="file" data-entity-uuid="' . $uuid . '" />';
-    $expected_output = '<img src="/' . $this->siteDirectory . '/files/llama.jpg" data-entity-type="file" data-entity-uuid="' . $uuid . '" ' . $dimensions . ' loading="lazy" />';
+    $expected_output = '<img src="/' . $this->siteDirectory . '/files/llama.jpg" data-entity-type="file" data-entity-uuid="' . $uuid . '" ' . $dimensions . ' />';
     $output = $test($input);
     $this->assertSame($expected_output, $output->getProcessedText());
     $this->assertEquals($cache_tag, $output->getCacheTags());
 
-    // Image dimensions and loading attributes are set manually.
-    $input = '<img src="llama.jpg" data-entity-type="file" data-entity-uuid="' . $uuid . '"width="41" height="21" loading="eager" />';
-    $expected_output = '<img src="/' . $this->siteDirectory . '/files/llama.jpg" data-entity-type="file" data-entity-uuid="' . $uuid . '" width="41" height="21" loading="eager" />';
+    // Image dimensions are set manually.
+    $input = '<img src="llama.jpg" data-entity-type="file" data-entity-uuid="' . $uuid . '"width="41" height="21" />';
+    $expected_output = '<img src="/' . $this->siteDirectory . '/files/llama.jpg" data-entity-type="file" data-entity-uuid="' . $uuid . '" width="41" height="21" />';
     $output = $test($input);
     $this->assertSame($expected_output, $output->getProcessedText());
     $this->assertEquals($cache_tag, $output->getCacheTags());
diff --git a/core/modules/filter/src/Plugin/Filter/FilterImageLazyLoad.php b/core/modules/filter/src/Plugin/Filter/FilterImageLazyLoad.php
new file mode 100644
index 00000000000..ee0802e1c8a
--- /dev/null
+++ b/core/modules/filter/src/Plugin/Filter/FilterImageLazyLoad.php
@@ -0,0 +1,59 @@
+<?php
+
+declare(strict_types = 1);
+
+namespace Drupal\filter\Plugin\Filter;
+
+use Drupal\Component\Utility\Html;
+use Drupal\filter\FilterProcessResult;
+use Drupal\filter\Plugin\FilterBase;
+
+/**
+ * Provides a filter to lazy load tracked images.
+ *
+ * @Filter(
+ *   id = "filter_image_lazy_load",
+ *   title = @Translation("Lazy load images"),
+ *   description = @Translation("Instruct browsers to lazy load images if dimensions are specified. Use in conjunction with and place after the 'Track images uploaded via a Text Editor' filter that adds image dimensions required for lazy loading. Results can be overridden by <code>&lt;img loading=&quot;eager&quot;&gt;</code>."),
+ *   type = Drupal\filter\Plugin\FilterInterface::TYPE_TRANSFORM_REVERSIBLE,
+ *   weight = 15
+ * )
+ */
+final class FilterImageLazyLoad extends FilterBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  public function process($text, $langcode): FilterProcessResult {
+    $result = new FilterProcessResult($text);
+
+    // If there are no images, return early.
+    if (stripos($text, '<img ') === FALSE && stripos($text, 'data-entity-type="file"') === FALSE) {
+      return $result;
+    }
+
+    return $result->setProcessedText($this->transformImages($text));
+  }
+
+  /**
+   * Transform markup of images to include loading="lazy".
+   *
+   * @param string $text
+   *   The markup to transform.
+   *
+   * @return string
+   *   The transformed text with loading attribute added.
+   */
+  private function transformImages(string $text): string {
+    $dom = Html::load($text);
+    $xpath = new \DOMXPath($dom);
+    // Only set loading="lazy" if no existing loading attribute is specified and
+    // dimensions are specified.
+    foreach ($xpath->query('//img[not(@loading="eager") and @width and @height]') as $element) {
+      assert($element instanceof \DOMElement);
+      $element->setAttribute('loading', 'lazy');
+    }
+    return Html::serialize($dom);
+  }
+
+}
diff --git a/core/modules/filter/tests/src/Unit/FilterImageLazyLoadTest.php b/core/modules/filter/tests/src/Unit/FilterImageLazyLoadTest.php
new file mode 100644
index 00000000000..6da46a4a55f
--- /dev/null
+++ b/core/modules/filter/tests/src/Unit/FilterImageLazyLoadTest.php
@@ -0,0 +1,86 @@
+<?php
+
+declare(strict_types = 1);
+
+namespace Drupal\Tests\filter\Unit;
+
+use Drupal\filter\Plugin\Filter\FilterImageLazyLoad;
+use Drupal\Tests\UnitTestCase;
+
+/**
+ * @coversDefaultClass \Drupal\filter\Plugin\Filter\FilterImageLazyLoad
+ * @group editor
+ */
+final class FilterImageLazyLoadTest extends UnitTestCase {
+
+  /**
+   * @var \Drupal\filter\Plugin\Filter\FilterImageLazyLoad
+   */
+  protected FilterImageLazyLoad $filter;
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function setUp(): void {
+    $this->filter = new FilterImageLazyLoad([], 'filter_image_lazy_load', ['provider' => 'test']);
+    parent::setUp();
+  }
+
+  /**
+   * @covers ::process
+   *
+   * @dataProvider providerHtml
+   *
+   * @param string $html
+   *   Input HTML.
+   * @param string $expected
+   *   The expected output string.
+   */
+  public function testProcess(string $html, string $expected): void {
+    $this->assertSame($expected, $this->filter->process($html, 'en')->getProcessedText());
+  }
+
+  /**
+   * Provides data for testProcess.
+   *
+   * @return array
+   *   An array of test data.
+   */
+  public function providerHtml(): array {
+    return [
+      'lazy loading attribute already added' => [
+        'input' => '<p><img src="foo.png" loading="lazy"></p>',
+        'output' => '<p><img src="foo.png" loading="lazy" /></p>',
+      ],
+      'eager loading attribute already added' => [
+        'input' => '<p><img src="foo.png" loading="eager"/></p>',
+        'output' => '<p><img src="foo.png" loading="eager" /></p>',
+      ],
+      'image dimensions provided' => [
+        'input' => '<p><img src="foo.png" width="200" height="200"/></p>',
+        '<p><img src="foo.png" width="200" height="200" loading="lazy" /></p>',
+      ],
+      'width image dimensions provided' => [
+        'input' => '<p><img src="foo.png" width="200"/></p>',
+        '<p><img src="foo.png" width="200" /></p>',
+      ],
+      'height image dimensions provided' => [
+        'input' => '<p><img src="foo.png" height="200"/></p>',
+        '<p><img src="foo.png" height="200" /></p>',
+      ],
+      'invalid loading attribute' => [
+        'input' => '<p><img src="foo.png" width="200" height="200" loading="foo"></p>',
+        'output' => '<p><img src="foo.png" width="200" height="200" loading="lazy" /></p>',
+      ],
+      'no image tag' => [
+        'input' => '<p>Lorem ipsum...</p>',
+        'output' => '<p>Lorem ipsum...</p>',
+      ],
+      'no image dimensions provided' => [
+        'input' => '<p><img src="foo.png"></p>',
+        'output' => '<p><img src="foo.png" /></p>',
+      ],
+    ];
+  }
+
+}
diff --git a/core/profiles/demo_umami/config/install/filter.format.basic_html.yml b/core/profiles/demo_umami/config/install/filter.format.basic_html.yml
index e3249c8561e..5c753e7f338 100644
--- a/core/profiles/demo_umami/config/install/filter.format.basic_html.yml
+++ b/core/profiles/demo_umami/config/install/filter.format.basic_html.yml
@@ -16,7 +16,7 @@ filters:
     status: true
     weight: -10
     settings:
-      allowed_html: '<a href hreflang> <em> <strong> <cite> <blockquote cite> <ul type> <ol start type> <li> <dl> <dt> <dd> <h2 id> <h3 id> <h4 id> <h5 id> <h6 id> <p> <br> <img src alt height width data-entity-type data-entity-uuid data-align data-caption> <drupal-media data-entity-type data-entity-uuid data-view-mode data-align data-caption alt title>'
+      allowed_html: '<a href hreflang> <em> <strong> <cite> <blockquote cite> <ul type> <ol start type> <li> <dl> <dt> <dd> <h2 id> <h3 id> <h4 id> <h5 id> <h6 id> <p> <br> <img src alt loading height width data-entity-type data-entity-uuid data-align data-caption> <drupal-media data-entity-type data-entity-uuid data-view-mode data-align data-caption alt title>'
       filter_html_help: false
       filter_html_nofollow: false
   filter_align:
@@ -49,6 +49,12 @@ filters:
     status: true
     weight: 0
     settings: {  }
+  filter_image_lazy_load:
+    id: filter_image_lazy_load
+    provider: filter
+    status: true
+    weight: 15
+    settings: { }
   media_embed:
     id: media_embed
     provider: media
diff --git a/core/profiles/demo_umami/config/install/filter.format.full_html.yml b/core/profiles/demo_umami/config/install/filter.format.full_html.yml
index edc3a24e3b3..3fbfbc87e62 100644
--- a/core/profiles/demo_umami/config/install/filter.format.full_html.yml
+++ b/core/profiles/demo_umami/config/install/filter.format.full_html.yml
@@ -28,6 +28,12 @@ filters:
     status: true
     weight: 10
     settings: {  }
+  filter_image_lazy_load:
+    id: filter_image_lazy_load
+    provider: filter
+    status: true
+    weight: 15
+    settings: { }
   editor_file_reference:
     id: editor_file_reference
     provider: editor
diff --git a/core/profiles/standard/config/install/filter.format.basic_html.yml b/core/profiles/standard/config/install/filter.format.basic_html.yml
index 7bf4073c917..60a4084ca61 100644
--- a/core/profiles/standard/config/install/filter.format.basic_html.yml
+++ b/core/profiles/standard/config/install/filter.format.basic_html.yml
@@ -36,6 +36,12 @@ filters:
     status: true
     weight: 9
     settings: {  }
+  filter_image_lazy_load:
+    id: filter_image_lazy_load
+    provider: filter
+    status: true
+    weight: 15
+    settings: {  }
   editor_file_reference:
     id: editor_file_reference
     provider: editor
diff --git a/core/profiles/standard/config/install/filter.format.full_html.yml b/core/profiles/standard/config/install/filter.format.full_html.yml
index 8aca83e0d9b..3a586cdd364 100644
--- a/core/profiles/standard/config/install/filter.format.full_html.yml
+++ b/core/profiles/standard/config/install/filter.format.full_html.yml
@@ -27,6 +27,12 @@ filters:
     status: true
     weight: 10
     settings: {  }
+  filter_image_lazy_load:
+    id: filter_image_lazy_load
+    provider: filter
+    status: true
+    weight: 15
+    settings: { }
   editor_file_reference:
     id: editor_file_reference
     provider: editor