├── README.md
├── phpunit.xml.dist
├── .gitignore
├── .editorconfig
├── composer.json
├── wp-lazy-loading.php
├── tests
    └── phpunit
    │   ├── bootstrap.php
    │   └── tests
    │       └── media.php
├── .travis.yml
├── readme.txt
├── functions.php
└── LICENSE


/README.md:
--------------------------------------------------------------------------------
1 | [![Build Status](https://img.shields.io/travis/com/WordPress/wp-lazy-loading/master.svg)](https://travis-ci.com/WordPress/wp-lazy-loading/)
2 | # Lazy Loading Feature Plugin
3 | 
4 | WordPress feature plugin for testing and experimenting with automatically adding the "loading" HTML attribute.
5 | 


--------------------------------------------------------------------------------
/phpunit.xml.dist:
--------------------------------------------------------------------------------
 1 | <?xml version="1.0"?>
 2 | <phpunit
 3 | 	backupGlobals="false"
 4 | 	backupStaticAttributes="false"
 5 | 	bootstrap="tests/phpunit/bootstrap.php"
 6 | 	colors="true"
 7 | 	convertErrorsToExceptions="true"
 8 | 	convertNoticesToExceptions="true"
 9 | 	convertWarningsToExceptions="true"
10 | 	processIsolation="false"
11 | 	stopOnError="false"
12 | 	stopOnFailure="false"
13 | 	stopOnIncomplete="false"
14 | 	stopOnSkipped="false"
15 | 	verbose="true"
16 | 	>
17 | 	<testsuites>
18 | 		<testsuite name="unit">
19 | 			<directory suffix=".php">./tests/phpunit/tests/</directory>
20 | 		</testsuite>
21 | 	</testsuites>
22 | 
23 | 	<filter>
24 | 		<whitelist>
25 | 			<directory>./src</directory>
26 | 		</whitelist>
27 | 	</filter>
28 | </phpunit>
29 | 


--------------------------------------------------------------------------------
/.gitignore:
--------------------------------------------------------------------------------
 1 | ############
 2 | ## IDEs
 3 | ############
 4 | 
 5 | *.pydevproject
 6 | .project
 7 | .metadata
 8 | *.swp
 9 | *~.nib
10 | local.properties
11 | .classpath
12 | .settings/
13 | .loadpath
14 | .externalToolBuilders/
15 | *.launch
16 | .cproject
17 | .buildpath
18 | nbproject/
19 | 
20 | ############
21 | ## Vendor
22 | ############
23 | 
24 | node_modules/
25 | vendor/
26 | 
27 | ############
28 | ## OSes
29 | ############
30 | 
31 | [Tt]humbs.db
32 | [Dd]esktop.ini
33 | *.DS_store
34 | .DS_store?
35 | 
36 | ############
37 | ## Misc
38 | ############
39 | 
40 | tests/logs
41 | bin/
42 | tmp/
43 | *.tmp
44 | *.bak
45 | *.log
46 | *.[Cc]ache
47 | *.cpr
48 | *.orig
49 | *.php.in
50 | .idea/
51 | .sass-cache/*
52 | temp/
53 | ._*
54 | .Trashes
55 | .svn
56 | 


--------------------------------------------------------------------------------
/.editorconfig:
--------------------------------------------------------------------------------
 1 | # WordPress Coding Standards
 2 | # https://make.wordpress.org/core/handbook/best-practices/coding-standards/
 3 | 
 4 | root = true
 5 | 
 6 | [*]
 7 | charset = utf-8
 8 | end_of_line = lf
 9 | indent_size = 4
10 | tab_width = 4
11 | indent_style = tab
12 | insert_final_newline = true
13 | trim_trailing_whitespace = true
14 | 
15 | [*.md]
16 | trim_trailing_whitespace = false
17 | indent_style = space
18 | indent_size = 2
19 | 
20 | [*.txt]
21 | trim_trailing_whitespace = false
22 | 
23 | [*.json]
24 | insert_final_newline = false
25 | indent_style = space
26 | indent_size = 2
27 | 
28 | [.*rc]
29 | insert_final_newline = false
30 | indent_style = space
31 | indent_size = 2
32 | 
33 | [*.yml]
34 | insert_final_newline = false
35 | indent_style = space
36 | indent_size = 2
37 | 


--------------------------------------------------------------------------------
/composer.json:
--------------------------------------------------------------------------------
 1 | {
 2 |   "name": "wordpress/wp-lazy-loading",
 3 |   "description": "WordPress feature plugin for testing and experimenting with automatically adding the loading HTML attribute.",
 4 |   "version": "1.0",
 5 |   "license": "GPL-2.0-or-later",
 6 |   "type": "wordpress-plugin",
 7 |   "keywords": [
 8 |     "feature plugin",
 9 |     "lazy loading"
10 |   ],
11 |   "homepage": "https://wordpress.org/plugins/wp-lazy-loading/",
12 |   "support": {
13 |     "issues": "https://github.com/WordPress/wp-lazy-loading/issues"
14 |   },
15 |   "config": {
16 |     "platform": {
17 |       "php": "5.6"
18 |     }
19 |   },
20 |   "require": {
21 |     "php": ">=5.6"
22 |   },
23 |   "require-dev": {
24 |     "phpunit/phpunit": ">4.8.20 <6.0"
25 |   },
26 |   "scripts": {
27 |     "test": "phpunit"
28 |   }
29 | }


--------------------------------------------------------------------------------
/wp-lazy-loading.php:
--------------------------------------------------------------------------------
 1 | <?php
 2 | /**
 3 |  * Plugin initialization file.
 4 |  *
 5 |  * @package WordPress
 6 |  *
 7 |  * @wordpress-plugin
 8 |  * Plugin Name: WP Lazy Loading
 9 |  * Plugin URI:  https://wordpress.org/plugins/wp-lazy-loading/
10 |  * Description: WordPress feature plugin for testing and experimenting with automatically adding the "loading" HTML attribute.
11 |  * Version:     1.1
12 |  * Author:      The WordPress Team
13 |  * Author URI:  https://github.com/WordPress/wp-lazy-loading/
14 |  * License:     GNU General Public License v2 (or later)
15 |  * License URI: http://www.gnu.org/licenses/gpl-2.0.html
16 |  *
17 |  * This program is free software; you can redistribute it and/or modify it under the terms of the GNU
18 |  * General Public License version 2, as published by the Free Software Foundation. You may NOT assume
19 |  * that you can use any other version of the GPL.
20 |  *
21 |  * This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without
22 |  * even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
23 |  */
24 | 
25 | if ( ! defined( 'ABSPATH' ) ) {
26 | 	die( 'Invalid request.' );
27 | }
28 | 
29 | /**
30 |  * Load only when needed.
31 |  */
32 | if (
33 | 	! function_exists( 'wp_lazy_loading_enabled' ) &&
34 | 	! function_exists( 'wp_filter_content_tags' ) &&
35 | 	! function_exists( 'wp_img_tag_add_loading_attr' ) &&
36 | 	! function_exists( 'wp_img_tag_add_srcset_and_sizes_attr' )
37 | ) {
38 | 	include_once plugin_dir_path( __FILE__ ) . 'functions.php';
39 | }
40 | 


--------------------------------------------------------------------------------
/tests/phpunit/bootstrap.php:
--------------------------------------------------------------------------------
 1 | <?php
 2 | /**
 3 |  * Tests bootstrap script.
 4 |  */
 5 | 
 6 | // Detect project directory.
 7 | define( 'TESTS_PLUGIN_DIR', dirname( dirname( __DIR__ ) ) );
 8 | 
 9 | // Disable xdebug backtrace.
10 | if ( function_exists( 'xdebug_disable' ) ) {
11 | 	xdebug_disable();
12 | }
13 | 
14 | if ( file_exists( TESTS_PLUGIN_DIR . '/vendor/autoload.php' ) ) {
15 | 	require_once TESTS_PLUGIN_DIR . '/vendor/autoload.php';
16 | }
17 | 
18 | if ( false !== getenv( 'WP_PLUGIN_DIR' ) ) {
19 | 	define( 'WP_PLUGIN_DIR', getenv( 'WP_PLUGIN_DIR' ) );
20 | } else {
21 | 	define( 'WP_PLUGIN_DIR', dirname( TESTS_PLUGIN_DIR ) );
22 | }
23 | 
24 | // Detect where to load the WordPress tests environment from.
25 | if ( false !== getenv( 'WP_TESTS_DIR' ) ) {
26 | 	$test_root = getenv( 'WP_TESTS_DIR' );
27 | } elseif ( false !== getenv( 'WP_DEVELOP_DIR' ) ) {
28 | 	$test_root = getenv( 'WP_DEVELOP_DIR' ) . '/tests/phpunit';
29 | } elseif ( file_exists( '/tmp/wordpress-tests-lib/includes/bootstrap.php' ) ) {
30 | 	$test_root = '/tmp/wordpress-tests-lib';
31 | } else {
32 | 	$test_root = dirname( dirname( dirname( dirname( TESTS_PLUGIN_DIR ) ) ) ) . '/tests/phpunit';
33 | }
34 | 
35 | // Ensure the methods annotated with the (unfixed) lazy-loading ticket are run.
36 | define( 'WP_TESTS_FORCE_KNOWN_BUGS', true );
37 | 
38 | // Ensure the plugin is loaded.
39 | $GLOBALS['wp_tests_options'] = array(
40 | 	'active_plugins' => array( basename( TESTS_PLUGIN_DIR ) . '/wp-lazy-loading.php' ),
41 | );
42 | 
43 | // Load the WordPress tests environment.
44 | require_once $test_root . '/includes/bootstrap.php';
45 | 


--------------------------------------------------------------------------------
/.travis.yml:
--------------------------------------------------------------------------------
 1 | sudo: false
 2 | dist: xenial
 3 | language: php
 4 | services:
 5 |   - mysql
 6 | cache:
 7 |   directories:
 8 |     - vendor
 9 |     - $HOME/.composer/cache
10 | matrix:
11 |   include:
12 |     - php: 7.4
13 |       env: TEST=1 WP_VERSION=latest
14 |     - php: 5.6
15 |       env: TEST=1 WP_VERSION=latest
16 |       dist: trusty
17 |     - php: 7.4
18 |       env: TEST=1 WP_VERSION=master
19 |   allow_failures:
20 |     - php: 7.4
21 |       env: TEST=1 WP_VERSION=master
22 | before_install:
23 |   - composer install
24 | before_script:
25 |   - |
26 |     if [[ "$TEST" == "1" ]]; then
27 |       if [[ "$WP_VERSION" == "latest" ]]; then
28 |         curl -s http://api.wordpress.org/core/version-check/1.7/ > /tmp/wp-latest.json
29 |         WP_VERSION=$(grep -o '"version":"[^"]*' /tmp/wp-latest.json | sed 's/"version":"//')
30 |       fi
31 |       PLUGIN_SLUG=$(basename $(pwd))
32 |       export WP_DEVELOP_DIR=/tmp/wordpress/
33 |       git clone --depth=50 --branch="$WP_VERSION" git://develop.git.wordpress.org/ /tmp/wordpress
34 |       cd ..
35 |       cp -r "$PLUGIN_SLUG" "/tmp/wordpress/src/wp-content/plugins/$PLUGIN_SLUG"
36 |       cd /tmp/wordpress/
37 |       cp wp-tests-config-sample.php wp-tests-config.php
38 |       sed -i "s/youremptytestdbnamehere/wordpress_tests/" wp-tests-config.php
39 |       sed -i "s/yourusernamehere/travis/" wp-tests-config.php
40 |       sed -i "s/yourpasswordhere//" wp-tests-config.php
41 |       mysql -e "CREATE DATABASE wordpress_tests;" -uroot
42 |       cd "/tmp/wordpress/src/wp-content/plugins/$PLUGIN_SLUG"
43 |     fi
44 |   - phpenv rehash
45 | script:
46 |   - |
47 |     if [[ "$TEST" == "1" ]]; then
48 |       composer run-script test
49 |     fi
50 | notifications:
51 |   email: false


--------------------------------------------------------------------------------
/readme.txt:
--------------------------------------------------------------------------------
 1 | === Lazy Loading Feature Plugin ===
 2 | Contributors: wordpressdotorg, azaozz, flixos90
 3 | Tags: feature plugin, lazy loading
 4 | Requires at least: 5.3
 5 | Tested up to: 5.4
 6 | Stable tag: 1.1
 7 | Requires PHP: 5.6.20
 8 | License: GPLv2 or later
 9 | License URI: http://www.gnu.org/licenses/gpl-2.0.html
10 | 
11 | WordPress feature plugin for testing and experimenting with automatically adding the "loading" HTML attribute. Not for production use.
12 | 
13 | == Description ==
14 | 
15 | Lazy Loading Feature Plugin is an official plugin maintained by the WordPress team. It is intended for testing of automatically adding the `loading` HTML attribute to images and other elements that support it.
16 | 
17 | More information about the `loading` attribute:
18 | Description: [https://developer.mozilla.org/en-US/docs/Web/HTML/Element/img#attr-loading](https://developer.mozilla.org/en-US/docs/Web/HTML/Element/img#attr-loading).
19 | HTML Specification: [https://html.spec.whatwg.org/multipage/embedded-content.html#attr-img-loading](https://html.spec.whatwg.org/multipage/embedded-content.html#attr-img-loading).
20 | 
21 | Currently the `loading` attribute is supported in the following browsers: [https://caniuse.com/#feat=loading-lazy-attr](https://caniuse.com/#feat=loading-lazy-attr).
22 | 
23 | To test, install and enable the plugin. It will automatically add `loading="lazy"` attributes to all images in all new and existing posts, pages, and text widgets on the front-end.
24 | 
25 | Then use one of the browsers that support it (Chrome, Opera, Firefox, Edge, Android, etc.) and visit the site. Best would be to test over a slower connection, with a phone, etc. and test web pages that have a lot of images, like gallery posts.
26 | 
27 | = Things to look for =
28 | 
29 | * Obvious bugs, for example images are missing.
30 | * Try to scroll down as soon as the page loads. All images should be at their places, and the page shouldn't "jump" when images are loaded.
31 | 
32 | = Note to developers =
33 | 
34 | This plugin is intended for testing. If the tests are successful, this functionality will be added to WordPress, but the exact code may change, perhaps significantly.
35 | 
36 | When testing, please also test the filters added by this plugin, and provide feedback at [https://github.com/WordPress/wp-lazy-loading](https://github.com/WordPress/wp-lazy-loading) or at [https://core.trac.wordpress.org/ticket/44427](https://core.trac.wordpress.org/ticket/44427).
37 | 
38 | == Changelog ==
39 | 
40 | Please see the Github repository: [https://github.com/WordPress/wp-lazy-loading](https://github.com/WordPress/wp-lazy-loading).
41 | 


--------------------------------------------------------------------------------
/tests/phpunit/tests/media.php:
--------------------------------------------------------------------------------
  1 | <?php
  2 | 
  3 | /**
  4 |  * @group media
  5 |  * @group shortcode
  6 |  */
  7 | class Tests_Media extends WP_UnitTestCase {
  8 | 	protected static $large_id;
  9 | 
 10 | 	public static function wpSetUpBeforeClass( $factory ) {
 11 | 		$filename       = DIR_TESTDATA . '/images/test-image-large.png';
 12 | 		self::$large_id = $factory->attachment->create_upload_object( $filename );
 13 | 	}
 14 | 
 15 | 	public static function wpTearDownAfterClass() {
 16 | 		wp_delete_post( self::$large_id, true );
 17 | 		self::$large_id = null;
 18 | 	}
 19 | 
 20 | 	/**
 21 | 	 * @ticket 44427
 22 | 	 */
 23 | 	function test_wp_lazy_load_content_media() {
 24 | 		$img       = get_image_tag( self::$large_id, '', '', '', 'medium' );
 25 | 		$img_xhtml = str_replace( ' />', '/>', $img );
 26 | 		$img_html5 = str_replace( ' />', '>', $img );
 27 | 		$iframe    = '<iframe src="https://www.example.com"></iframe>';
 28 | 
 29 | 		$lazy_img       = str_replace( '<img ', '<img loading="lazy" ', $img );
 30 | 		$lazy_img_xhtml = str_replace( '<img ', '<img loading="lazy" ', $img_xhtml );
 31 | 		$lazy_img_html5 = str_replace( '<img ', '<img loading="lazy" ', $img_html5 );
 32 | 
 33 | 		// The following should not be modified because there already is a 'loading' attribute.
 34 | 		$img_eager = str_replace( ' />', ' loading="eager" />', $img );
 35 | 
 36 | 		$content = '
 37 | 			<p>Image, standard.</p>
 38 | 			%1$s
 39 | 
 40 | 			<p>Image, XHTML 1.0 style (no space before the closing slash).</p>
 41 | 			%2$s
 42 | 
 43 | 			<p>Image, HTML 5.0 style.</p>
 44 | 			%3$s
 45 | 
 46 | 			<p>Image, with pre-existing "loading" attribute.</p>
 47 | 			%5$s
 48 | 
 49 | 			<p>Iframe, standard. Should not be modified.</p>
 50 | 			%4$s';
 51 | 
 52 | 		$content_unfiltered = sprintf( $content, $img, $img_xhtml, $img_html5, $iframe, $img_eager );
 53 | 		$content_filtered   = sprintf( $content, $lazy_img, $lazy_img_xhtml, $lazy_img_html5, $iframe, $img_eager );
 54 | 
 55 | 		// Do not add srcset and sizes while testing.
 56 | 		add_filter( 'wp_img_tag_add_srcset_and_sizes_attr', '__return_false' );
 57 | 
 58 | 		$this->assertSame( $content_filtered, wp_filter_content_tags( $content_unfiltered ) );
 59 | 
 60 | 		remove_filter( 'wp_img_tag_add_srcset_and_sizes_attr', '__return_false' );
 61 | 	}
 62 | 
 63 | 	/**
 64 | 	 * @ticket 44427
 65 | 	 */
 66 | 	function test_wp_lazy_load_content_media_opted_in() {
 67 | 		$img = get_image_tag( self::$large_id, '', '', '', 'medium' );
 68 | 
 69 | 		$lazy_img = str_replace( '<img ', '<img loading="lazy" ', $img );
 70 | 
 71 | 		$content = '
 72 | 			<p>Image, standard.</p>
 73 | 			%1$s';
 74 | 
 75 | 		$content_unfiltered = sprintf( $content, $img );
 76 | 		$content_filtered   = sprintf( $content, $lazy_img );
 77 | 
 78 | 		// Do not add srcset and sizes while testing.
 79 | 		add_filter( 'wp_img_tag_add_srcset_and_sizes_attr', '__return_false' );
 80 | 
 81 | 		// Enable globally for all tags.
 82 | 		add_filter( 'wp_lazy_loading_enabled', '__return_true' );
 83 | 
 84 | 		$this->assertSame( $content_filtered, wp_filter_content_tags( $content_unfiltered ) );
 85 | 		remove_filter( 'wp_lazy_loading_enabled', '__return_true' );
 86 | 		remove_filter( 'wp_img_tag_add_srcset_and_sizes_attr', '__return_false' );
 87 | 	}
 88 | 
 89 | 	/**
 90 | 	 * @ticket 44427
 91 | 	 */
 92 | 	function test_wp_lazy_load_content_media_opted_out() {
 93 | 		$img = get_image_tag( self::$large_id, '', '', '', 'medium' );
 94 | 
 95 | 		$content = '
 96 | 			<p>Image, standard.</p>
 97 | 			%1$s';
 98 | 		$content = sprintf( $content, $img );
 99 | 
100 | 		// Do not add srcset and sizes while testing.
101 | 		add_filter( 'wp_img_tag_add_srcset_and_sizes_attr', '__return_false' );
102 | 
103 | 		// Disable globally for all tags.
104 | 		add_filter( 'wp_lazy_loading_enabled', '__return_false' );
105 | 
106 | 		$this->assertSame( $content, wp_filter_content_tags( $content ) );
107 | 		remove_filter( 'wp_lazy_loading_enabled', '__return_false' );
108 | 		remove_filter( 'wp_img_tag_add_srcset_and_sizes_attr', '__return_false' );
109 | 	}
110 | }
111 | 


--------------------------------------------------------------------------------
/functions.php:
--------------------------------------------------------------------------------
  1 | <?php
  2 | /**
  3 |  * Part of the WP Lazy Loading feature plugin.
  4 |  */
  5 | 
  6 | if ( ! defined( 'ABSPATH' ) ) {
  7 | 	die( 'Invalid request.' );
  8 | }
  9 | 
 10 | /**
 11 |  * Initialise filters and actions.
 12 |  */
 13 | function _wp_lazy_loading_initialize_filters() {
 14 | 	// The following filters would be merged into core.
 15 | 	foreach ( array( 'the_content', 'the_excerpt', 'widget_text_content' ) as $filter ) {
 16 | 		add_filter( $filter, 'wp_filter_content_tags' );
 17 | 	}
 18 | 
 19 | 	// The following filters are only needed while this is a feature plugin.
 20 | 	add_filter( 'wp_get_attachment_image_attributes', '_wp_lazy_loading_add_attribute_to_attachment_image' );
 21 | 	add_filter( 'get_avatar', '_wp_lazy_loading_add_attribute_to_avatar' );
 22 | 
 23 | 	// The following relevant filter from core should be removed when merged.
 24 | 	remove_filter( 'the_content', 'wp_make_content_images_responsive' );
 25 | }
 26 | 
 27 | add_action( 'plugins_loaded', '_wp_lazy_loading_initialize_filters', 1 );
 28 | 
 29 | 
 30 | // The following functions are only needed while this is a plugin.
 31 | 
 32 | /**
 33 |  * Adds loading attribute to an avatar image tag.
 34 |  *
 35 |  * If merged to core, this should instead happen directly in
 36 |  * {@see get_avatar()}, as a default attribute.
 37 |  *
 38 |  * @since 1.0
 39 |  * @access private
 40 |  * @see get_avatar()
 41 |  *
 42 |  * @param string $avatar Avatar image tag markup.
 43 |  * @return string Modified tag.
 44 |  */
 45 | function _wp_lazy_loading_add_attribute_to_avatar( $avatar ) {
 46 | 	if ( wp_lazy_loading_enabled( 'img', 'get_avatar' ) && false === strpos( $avatar, ' loading=' ) ) {
 47 | 		$avatar = str_replace( '<img ', '<img loading="lazy" ', $avatar );
 48 | 	}
 49 | 
 50 | 	return $avatar;
 51 | }
 52 | 
 53 | /**
 54 |  * Adds loading attribute to an attachment image tag.
 55 |  *
 56 |  * If merged to core, this should instead happen directly in
 57 |  * {@see wp_get_attachment_image()}, as a default attribute.
 58 |  *
 59 |  * @since 1.0
 60 |  * @access private
 61 |  * @see wp_get_attachment_image()
 62 |  *
 63 |  * @param array $attr Associative array of attributes for the image tag.
 64 |  * @return array Modified attributes.
 65 |  */
 66 | function _wp_lazy_loading_add_attribute_to_attachment_image( $attr ) {
 67 | 	if ( wp_lazy_loading_enabled( 'img', 'wp_get_attachment_image' ) && ! isset( $attr['loading'] ) ) {
 68 | 		$attr['loading'] = 'lazy';
 69 | 	}
 70 | 
 71 | 	return $attr;
 72 | }
 73 | 
 74 | 
 75 | // The following functions will be merged to core.
 76 | 
 77 | /**
 78 |  * Determine whether to add the `loading` attribute to the specified tag in the specified context.
 79 |  *
 80 |  * @since (TBD)
 81 |  *
 82 |  * @param string  $tag_name The tag name.
 83 |  * @param string  $context Additional context, like the current filter name or the function name from where this was called.
 84 |  * @return boolean Whether to add the attribute.
 85 |  */
 86 | function wp_lazy_loading_enabled( $tag_name, $context ) {
 87 | 	// By default add to all 'img' tags.
 88 | 	// See https://html.spec.whatwg.org/multipage/embedded-content.html#attr-img-loading
 89 | 	$default = ( 'img' === $tag_name );
 90 | 
 91 | 	/**
 92 | 	 * Filters whether to add the `loading` attribute to the specified tag in the specified context.
 93 | 	 *
 94 | 	 * @since (TBD)
 95 | 	 *
 96 | 	 * @param boolean $default Default value.
 97 | 	 * @param string  $tag_name The tag name.
 98 | 	 * @param string  $context Additional context, like the current filter name or the function name from where this was called.
 99 | 	 */
100 | 	return (bool) apply_filters( 'wp_lazy_loading_enabled', $default, $tag_name, $context );
101 | }
102 | 
103 | /**
104 |  * Filters specific tags in post content and modifies their markup.
105 |  *
106 |  * This function adds `srcset`, `sizes`, and `loading` attributes to `img` HTML tags.
107 |  *
108 |  * @since (TBD)
109 |  *
110 |  * @see wp_img_tag_add_loading_attr()
111 |  * @see wp_img_tag_add_srcset_and_sizes_attr()
112 |  *
113 |  * @param string $content The HTML content to be filtered.
114 |  * @param string $context Optional. Additional context to pass to the filters. Defaults to `current_filter()` when not set.
115 |  * @return string Converted content with images modified.
116 |  */
117 | function wp_filter_content_tags( $content, $context = null ) {
118 | 	if ( null === $context ) {
119 | 		$context = current_filter();
120 | 	}
121 | 
122 | 	$add_loading_attr = wp_lazy_loading_enabled( 'img', $context );
123 | 
124 | 	if ( false === strpos( $content, '<img' ) ) {
125 | 		return $content;
126 | 	}
127 | 
128 | 	if ( ! preg_match_all( '/<img\s[^>]+>/', $content, $matches ) ) {
129 | 		return $content;
130 | 	}
131 | 
132 | 	// List of the unique `img` tags found in $content.
133 | 	$images = array();
134 | 
135 | 	foreach ( $matches[0] as $image ) {
136 | 		if ( preg_match( '/wp-image-([0-9]+)/i', $image, $class_id ) ) {
137 | 			$attachment_id = absint( $class_id[1] );
138 | 
139 | 			if ( $attachment_id ) {
140 | 				/*
141 | 				 * If exactly the same image tag is used more than once, overwrite it.
142 | 				 * All identical tags will be replaced later with 'str_replace()'.
143 | 				 */
144 | 				$images[ $image ] = $attachment_id;
145 | 				continue;
146 | 			}
147 | 		}
148 | 
149 | 		$images[ $image ] = 0;
150 | 	}
151 | 
152 | 	// Reduce the array to unique attachment IDs.
153 | 	$attachment_ids = array_unique( array_filter( array_values( $images ) ) );
154 | 
155 | 	if ( count( $attachment_ids ) > 1 ) {
156 | 		/*
157 | 		 * Warm the object cache with post and meta information for all found
158 | 		 * images to avoid making individual database calls.
159 | 		 */
160 | 		_prime_post_caches( $attachment_ids, false, true );
161 | 	}
162 | 
163 | 	foreach ( $images as $image => $attachment_id ) {
164 | 		$filtered_image = $image;
165 | 
166 | 		// Add 'srcset' and 'sizes' attributes if applicable.
167 | 		if ( $attachment_id > 0 && false === strpos( $filtered_image, ' srcset=' ) ) {
168 | 			$filtered_image = wp_img_tag_add_srcset_and_sizes_attr( $filtered_image, $context, $attachment_id );
169 | 		}
170 | 
171 | 		// Add 'loading' attribute if applicable.
172 | 		if ( $add_loading_attr && false === strpos( $filtered_image, ' loading=' ) ) {
173 | 			$filtered_image = wp_img_tag_add_loading_attr( $filtered_image, $context );
174 | 		}
175 | 
176 | 		if ( $filtered_image !== $image ) {
177 | 			$content = str_replace( $image, $filtered_image, $content );
178 | 		}
179 | 	}
180 | 
181 | 	return $content;
182 | }
183 | 
184 | /**
185 |  * Adds `loading` attribute to an existing `img` HTML tag.
186 |  *
187 |  * @since (TBD)
188 |  *
189 |  * @param string $image   The HTML `img` tag where the attribute should be added.
190 |  * @param string $context Additional context to pass to the filters.
191 |  * @return string Converted `img` tag with `loading` attribute added.
192 |  */
193 | function wp_img_tag_add_loading_attr( $image, $context ) {
194 | 	/**
195 | 	 * Filters the `loading` attribute value. Default `lazy`.
196 | 	 *
197 | 	 * Returning `false` or an empty string will not add the attribute.
198 | 	 * Returning `true` will add the default value.
199 | 	 *
200 | 	 * @since (TBD)
201 | 	 *
202 | 	 * @param string $value   The 'loading' attribute value, defaults to `lazy`.
203 | 	 * @param string $image   The HTML 'img' element to be filtered.
204 | 	 * @param string $context Additional context about how the function was called or where the img tag is.
205 | 	 */
206 | 	$value = apply_filters( 'wp_img_tag_add_loading_attr', 'lazy', $image, $context );
207 | 
208 | 	if ( $value ) {
209 | 		if ( ! in_array( $value, array( 'lazy', 'eager' ), true ) ) {
210 | 			$value = 'lazy';
211 | 		}
212 | 
213 | 		return str_replace( '<img', '<img loading="' . $value . '"', $image );
214 | 	}
215 | 
216 | 	return $image;
217 | }
218 | 
219 | /**
220 |  * Adds `srcset` and `sizes` attributes to an existing `img` HTML tag.
221 |  *
222 |  * @since (TBD)
223 |  *
224 |  * @param string $image         The HTML `img` tag where the attribute should be added.
225 |  * @param string $context       Additional context to pass to the filters.
226 |  * @param int    $attachment_id Image attachment ID.
227 |  * @return string Converted 'img' element with 'loading' attribute added.
228 |  */
229 | function wp_img_tag_add_srcset_and_sizes_attr( $image, $context, $attachment_id ) {
230 | 	/**
231 | 	 * Filters whether to add the `srcset` and `sizes` HTML attributes to the img tag. Default `true`.
232 | 	 *
233 | 	 * Returning anything else than `true` will not add the attributes.
234 | 	 *
235 | 	 * @since (TBD)
236 | 	 *
237 | 	 * @param bool   $value         The filtered value, defaults to `true`.
238 | 	 * @param string $image         The HTML `img` tag where the attribute should be added.
239 | 	 * @param string $context       Additional context about how the function was called or where the img tag is.
240 | 	 * @param int    $attachment_id The image attachment ID.
241 | 	 */
242 | 	$add = apply_filters( 'wp_img_tag_add_srcset_and_sizes_attr', true, $image, $context, $attachment_id );
243 | 
244 | 	if ( true === $add ) {
245 | 		$image_meta = wp_get_attachment_metadata( $attachment_id );
246 | 		return wp_image_add_srcset_and_sizes( $image, $image_meta, $attachment_id );
247 | 	}
248 | 
249 | 	return $image;
250 | }
251 | 


--------------------------------------------------------------------------------
/LICENSE:
--------------------------------------------------------------------------------
  1 |                     GNU GENERAL PUBLIC LICENSE
  2 |                        Version 2, June 1991
  3 | 
  4 |  Copyright (C) 1989, 1991 Free Software Foundation, Inc.,
  5 |  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  6 |  Everyone is permitted to copy and distribute verbatim copies
  7 |  of this license document, but changing it is not allowed.
  8 | 
  9 |                             Preamble
 10 | 
 11 |   The licenses for most software are designed to take away your
 12 | freedom to share and change it.  By contrast, the GNU General Public
 13 | License is intended to guarantee your freedom to share and change free
 14 | software--to make sure the software is free for all its users.  This
 15 | General Public License applies to most of the Free Software
 16 | Foundation's software and to any other program whose authors commit to
 17 | using it.  (Some other Free Software Foundation software is covered by
 18 | the GNU Lesser General Public License instead.)  You can apply it to
 19 | your programs, too.
 20 | 
 21 |   When we speak of free software, we are referring to freedom, not
 22 | price.  Our General Public Licenses are designed to make sure that you
 23 | have the freedom to distribute copies of free software (and charge for
 24 | this service if you wish), that you receive source code or can get it
 25 | if you want it, that you can change the software or use pieces of it
 26 | in new free programs; and that you know you can do these things.
 27 | 
 28 |   To protect your rights, we need to make restrictions that forbid
 29 | anyone to deny you these rights or to ask you to surrender the rights.
 30 | These restrictions translate to certain responsibilities for you if you
 31 | distribute copies of the software, or if you modify it.
 32 | 
 33 |   For example, if you distribute copies of such a program, whether
 34 | gratis or for a fee, you must give the recipients all the rights that
 35 | you have.  You must make sure that they, too, receive or can get the
 36 | source code.  And you must show them these terms so they know their
 37 | rights.
 38 | 
 39 |   We protect your rights with two steps: (1) copyright the software, and
 40 | (2) offer you this license which gives you legal permission to copy,
 41 | distribute and/or modify the software.
 42 | 
 43 |   Also, for each author's protection and ours, we want to make certain
 44 | that everyone understands that there is no warranty for this free
 45 | software.  If the software is modified by someone else and passed on, we
 46 | want its recipients to know that what they have is not the original, so
 47 | that any problems introduced by others will not reflect on the original
 48 | authors' reputations.
 49 | 
 50 |   Finally, any free program is threatened constantly by software
 51 | patents.  We wish to avoid the danger that redistributors of a free
 52 | program will individually obtain patent licenses, in effect making the
 53 | program proprietary.  To prevent this, we have made it clear that any
 54 | patent must be licensed for everyone's free use or not licensed at all.
 55 | 
 56 |   The precise terms and conditions for copying, distribution and
 57 | modification follow.
 58 | 
 59 |                     GNU GENERAL PUBLIC LICENSE
 60 |    TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION
 61 | 
 62 |   0. This License applies to any program or other work which contains
 63 | a notice placed by the copyright holder saying it may be distributed
 64 | under the terms of this General Public License.  The "Program", below,
 65 | refers to any such program or work, and a "work based on the Program"
 66 | means either the Program or any derivative work under copyright law:
 67 | that is to say, a work containing the Program or a portion of it,
 68 | either verbatim or with modifications and/or translated into another
 69 | language.  (Hereinafter, translation is included without limitation in
 70 | the term "modification".)  Each licensee is addressed as "you".
 71 | 
 72 | Activities other than copying, distribution and modification are not
 73 | covered by this License; they are outside its scope.  The act of
 74 | running the Program is not restricted, and the output from the Program
 75 | is covered only if its contents constitute a work based on the
 76 | Program (independent of having been made by running the Program).
 77 | Whether that is true depends on what the Program does.
 78 | 
 79 |   1. You may copy and distribute verbatim copies of the Program's
 80 | source code as you receive it, in any medium, provided that you
 81 | conspicuously and appropriately publish on each copy an appropriate
 82 | copyright notice and disclaimer of warranty; keep intact all the
 83 | notices that refer to this License and to the absence of any warranty;
 84 | and give any other recipients of the Program a copy of this License
 85 | along with the Program.
 86 | 
 87 | You may charge a fee for the physical act of transferring a copy, and
 88 | you may at your option offer warranty protection in exchange for a fee.
 89 | 
 90 |   2. You may modify your copy or copies of the Program or any portion
 91 | of it, thus forming a work based on the Program, and copy and
 92 | distribute such modifications or work under the terms of Section 1
 93 | above, provided that you also meet all of these conditions:
 94 | 
 95 |     a) You must cause the modified files to carry prominent notices
 96 |     stating that you changed the files and the date of any change.
 97 | 
 98 |     b) You must cause any work that you distribute or publish, that in
 99 |     whole or in part contains or is derived from the Program or any
100 |     part thereof, to be licensed as a whole at no charge to all third
101 |     parties under the terms of this License.
102 | 
103 |     c) If the modified program normally reads commands interactively
104 |     when run, you must cause it, when started running for such
105 |     interactive use in the most ordinary way, to print or display an
106 |     announcement including an appropriate copyright notice and a
107 |     notice that there is no warranty (or else, saying that you provide
108 |     a warranty) and that users may redistribute the program under
109 |     these conditions, and telling the user how to view a copy of this
110 |     License.  (Exception: if the Program itself is interactive but
111 |     does not normally print such an announcement, your work based on
112 |     the Program is not required to print an announcement.)
113 | 
114 | These requirements apply to the modified work as a whole.  If
115 | identifiable sections of that work are not derived from the Program,
116 | and can be reasonably considered independent and separate works in
117 | themselves, then this License, and its terms, do not apply to those
118 | sections when you distribute them as separate works.  But when you
119 | distribute the same sections as part of a whole which is a work based
120 | on the Program, the distribution of the whole must be on the terms of
121 | this License, whose permissions for other licensees extend to the
122 | entire whole, and thus to each and every part regardless of who wrote it.
123 | 
124 | Thus, it is not the intent of this section to claim rights or contest
125 | your rights to work written entirely by you; rather, the intent is to
126 | exercise the right to control the distribution of derivative or
127 | collective works based on the Program.
128 | 
129 | In addition, mere aggregation of another work not based on the Program
130 | with the Program (or with a work based on the Program) on a volume of
131 | a storage or distribution medium does not bring the other work under
132 | the scope of this License.
133 | 
134 |   3. You may copy and distribute the Program (or a work based on it,
135 | under Section 2) in object code or executable form under the terms of
136 | Sections 1 and 2 above provided that you also do one of the following:
137 | 
138 |     a) Accompany it with the complete corresponding machine-readable
139 |     source code, which must be distributed under the terms of Sections
140 |     1 and 2 above on a medium customarily used for software interchange; or,
141 | 
142 |     b) Accompany it with a written offer, valid for at least three
143 |     years, to give any third party, for a charge no more than your
144 |     cost of physically performing source distribution, a complete
145 |     machine-readable copy of the corresponding source code, to be
146 |     distributed under the terms of Sections 1 and 2 above on a medium
147 |     customarily used for software interchange; or,
148 | 
149 |     c) Accompany it with the information you received as to the offer
150 |     to distribute corresponding source code.  (This alternative is
151 |     allowed only for noncommercial distribution and only if you
152 |     received the program in object code or executable form with such
153 |     an offer, in accord with Subsection b above.)
154 | 
155 | The source code for a work means the preferred form of the work for
156 | making modifications to it.  For an executable work, complete source
157 | code means all the source code for all modules it contains, plus any
158 | associated interface definition files, plus the scripts used to
159 | control compilation and installation of the executable.  However, as a
160 | special exception, the source code distributed need not include
161 | anything that is normally distributed (in either source or binary
162 | form) with the major components (compiler, kernel, and so on) of the
163 | operating system on which the executable runs, unless that component
164 | itself accompanies the executable.
165 | 
166 | If distribution of executable or object code is made by offering
167 | access to copy from a designated place, then offering equivalent
168 | access to copy the source code from the same place counts as
169 | distribution of the source code, even though third parties are not
170 | compelled to copy the source along with the object code.
171 | 
172 |   4. You may not copy, modify, sublicense, or distribute the Program
173 | except as expressly provided under this License.  Any attempt
174 | otherwise to copy, modify, sublicense or distribute the Program is
175 | void, and will automatically terminate your rights under this License.
176 | However, parties who have received copies, or rights, from you under
177 | this License will not have their licenses terminated so long as such
178 | parties remain in full compliance.
179 | 
180 |   5. You are not required to accept this License, since you have not
181 | signed it.  However, nothing else grants you permission to modify or
182 | distribute the Program or its derivative works.  These actions are
183 | prohibited by law if you do not accept this License.  Therefore, by
184 | modifying or distributing the Program (or any work based on the
185 | Program), you indicate your acceptance of this License to do so, and
186 | all its terms and conditions for copying, distributing or modifying
187 | the Program or works based on it.
188 | 
189 |   6. Each time you redistribute the Program (or any work based on the
190 | Program), the recipient automatically receives a license from the
191 | original licensor to copy, distribute or modify the Program subject to
192 | these terms and conditions.  You may not impose any further
193 | restrictions on the recipients' exercise of the rights granted herein.
194 | You are not responsible for enforcing compliance by third parties to
195 | this License.
196 | 
197 |   7. If, as a consequence of a court judgment or allegation of patent
198 | infringement or for any other reason (not limited to patent issues),
199 | conditions are imposed on you (whether by court order, agreement or
200 | otherwise) that contradict the conditions of this License, they do not
201 | excuse you from the conditions of this License.  If you cannot
202 | distribute so as to satisfy simultaneously your obligations under this
203 | License and any other pertinent obligations, then as a consequence you
204 | may not distribute the Program at all.  For example, if a patent
205 | license would not permit royalty-free redistribution of the Program by
206 | all those who receive copies directly or indirectly through you, then
207 | the only way you could satisfy both it and this License would be to
208 | refrain entirely from distribution of the Program.
209 | 
210 | If any portion of this section is held invalid or unenforceable under
211 | any particular circumstance, the balance of the section is intended to
212 | apply and the section as a whole is intended to apply in other
213 | circumstances.
214 | 
215 | It is not the purpose of this section to induce you to infringe any
216 | patents or other property right claims or to contest validity of any
217 | such claims; this section has the sole purpose of protecting the
218 | integrity of the free software distribution system, which is
219 | implemented by public license practices.  Many people have made
220 | generous contributions to the wide range of software distributed
221 | through that system in reliance on consistent application of that
222 | system; it is up to the author/donor to decide if he or she is willing
223 | to distribute software through any other system and a licensee cannot
224 | impose that choice.
225 | 
226 | This section is intended to make thoroughly clear what is believed to
227 | be a consequence of the rest of this License.
228 | 
229 |   8. If the distribution and/or use of the Program is restricted in
230 | certain countries either by patents or by copyrighted interfaces, the
231 | original copyright holder who places the Program under this License
232 | may add an explicit geographical distribution limitation excluding
233 | those countries, so that distribution is permitted only in or among
234 | countries not thus excluded.  In such case, this License incorporates
235 | the limitation as if written in the body of this License.
236 | 
237 |   9. The Free Software Foundation may publish revised and/or new versions
238 | of the General Public License from time to time.  Such new versions will
239 | be similar in spirit to the present version, but may differ in detail to
240 | address new problems or concerns.
241 | 
242 | Each version is given a distinguishing version number.  If the Program
243 | specifies a version number of this License which applies to it and "any
244 | later version", you have the option of following the terms and conditions
245 | either of that version or of any later version published by the Free
246 | Software Foundation.  If the Program does not specify a version number of
247 | this License, you may choose any version ever published by the Free Software
248 | Foundation.
249 | 
250 |   10. If you wish to incorporate parts of the Program into other free
251 | programs whose distribution conditions are different, write to the author
252 | to ask for permission.  For software which is copyrighted by the Free
253 | Software Foundation, write to the Free Software Foundation; we sometimes
254 | make exceptions for this.  Our decision will be guided by the two goals
255 | of preserving the free status of all derivatives of our free software and
256 | of promoting the sharing and reuse of software generally.
257 | 
258 |                             NO WARRANTY
259 | 
260 |   11. BECAUSE THE PROGRAM IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY
261 | FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW.  EXCEPT WHEN
262 | OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES
263 | PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED
264 | OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
265 | MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.  THE ENTIRE RISK AS
266 | TO THE QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU.  SHOULD THE
267 | PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING,
268 | REPAIR OR CORRECTION.
269 | 
270 |   12. IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
271 | WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR
272 | REDISTRIBUTE THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES,
273 | INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING
274 | OUT OF THE USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED
275 | TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY
276 | YOU OR THIRD PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER
277 | PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE
278 | POSSIBILITY OF SUCH DAMAGES.
279 | 
280 |                      END OF TERMS AND CONDITIONS
281 | 
282 |             How to Apply These Terms to Your New Programs
283 | 
284 |   If you develop a new program, and you want it to be of the greatest
285 | possible use to the public, the best way to achieve this is to make it
286 | free software which everyone can redistribute and change under these terms.
287 | 
288 |   To do so, attach the following notices to the program.  It is safest
289 | to attach them to the start of each source file to most effectively
290 | convey the exclusion of warranty; and each file should have at least
291 | the "copyright" line and a pointer to where the full notice is found.
292 | 
293 |     <one line to give the program's name and a brief idea of what it does.>
294 |     Copyright (C) <year>  <name of author>
295 | 
296 |     This program is free software; you can redistribute it and/or modify
297 |     it under the terms of the GNU General Public License as published by
298 |     the Free Software Foundation; either version 2 of the License, or
299 |     (at your option) any later version.
300 | 
301 |     This program is distributed in the hope that it will be useful,
302 |     but WITHOUT ANY WARRANTY; without even the implied warranty of
303 |     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
304 |     GNU General Public License for more details.
305 | 
306 |     You should have received a copy of the GNU General Public License along
307 |     with this program; if not, write to the Free Software Foundation, Inc.,
308 |     51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
309 | 
310 | Also add information on how to contact you by electronic and paper mail.
311 | 
312 | If the program is interactive, make it output a short notice like this
313 | when it starts in an interactive mode:
314 | 
315 |     Gnomovision version 69, Copyright (C) year name of author
316 |     Gnomovision comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
317 |     This is free software, and you are welcome to redistribute it
318 |     under certain conditions; type `show c' for details.
319 | 
320 | The hypothetical commands `show w' and `show c' should show the appropriate
321 | parts of the General Public License.  Of course, the commands you use may
322 | be called something other than `show w' and `show c'; they could even be
323 | mouse-clicks or menu items--whatever suits your program.
324 | 
325 | You should also get your employer (if you work as a programmer) or your
326 | school, if any, to sign a "copyright disclaimer" for the program, if
327 | necessary.  Here is a sample; alter the names:
328 | 
329 |   Yoyodyne, Inc., hereby disclaims all copyright interest in the program
330 |   `Gnomovision' (which makes passes at compilers) written by James Hacker.
331 | 
332 |   <signature of Ty Coon>, 1 April 1989
333 |   Ty Coon, President of Vice
334 | 
335 | This General Public License does not permit incorporating your program into
336 | proprietary programs.  If your program is a subroutine library, you may
337 | consider it more useful to permit linking proprietary applications with the
338 | library.  If this is what you want to do, use the GNU Lesser General
339 | Public License instead of this License.
340 | 


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