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Diffstat (limited to 'plugins/jetpack/jetpack_vendor/automattic/jetpack-lazy-images/src/lazy-images.php')
| -rw-r--r-- | plugins/jetpack/jetpack_vendor/automattic/jetpack-lazy-images/src/lazy-images.php | 516 |
1 files changed, 516 insertions, 0 deletions
diff --git a/plugins/jetpack/jetpack_vendor/automattic/jetpack-lazy-images/src/lazy-images.php b/plugins/jetpack/jetpack_vendor/automattic/jetpack-lazy-images/src/lazy-images.php new file mode 100644 index 00000000..8be08ed5 --- /dev/null +++ b/plugins/jetpack/jetpack_vendor/automattic/jetpack-lazy-images/src/lazy-images.php @@ -0,0 +1,516 @@ +<?php // phpcs:ignore WordPress.Files.FileName.InvalidClassFileName + +/** + * The Lazy Images package. + * + * @since 1.0.0 + * @since-jetpack 8.8.0 + * + * This package has been lifted from the Jetpack modules folder and adapted to be + * an standalone package reusable outside Jetpack. + * + * @package automattic/jetpack-lazy-images + */ + +/** + * This package relies heavily upon the Lazy Load plugin which was worked on by + * Mohammad Jangda (batmoo), the WordPress.com VIP team, the TechCrunch 2011 + * redesign team, and Jake Goldman of 10up LLC. + * + * The JavaScript has been updated to rely on InterSection observer instead of + * jQuery Sonar. Many thanks to Dean Hume (deanhume) and his example: + * https://github.com/deanhume/lazy-observer-load + */ + +namespace Automattic\Jetpack; + +/** + * Class Automattic\Jetpack\Jetpack_Lazy_Images + * + * @since 1.0.0 + * @since-jetpack 8.8.0 + */ +class Jetpack_Lazy_Images { + + /** + * Class instance. + * + * @since 1.0.0 + * @since-jetpack 5.6.0 + * + * @var null + */ + private static $instance = null; + + /** + * Singleton implementation. + * + * @since 1.0.0 + * @since-jetpack 5.6.0 + * + * @return object The class instance. + */ + public static function instance() { + if ( is_null( self::$instance ) ) { + self::$instance = new Jetpack_Lazy_Images(); + } + + return self::$instance; + } + + /** + * Check if the request is a AMP request. + * + * @since 1.0.0 + * @since-jetpack 8.8.0 + * + * @return bool + */ + public static function is_amp_request() { + $is_amp_request = ( function_exists( 'is_amp_endpoint' ) && is_amp_endpoint() ); + + /** + * Returns true if the current request should return valid AMP content. + * + * @since 1.0.0 + * @since-jetpack 8.8.0 + * + * @param boolean $is_amp_request Is this request supposed to return valid AMP content? + */ + return apply_filters( 'jetpack_lazy_images_is_amp_request', $is_amp_request ); + } + + /** + * Registers actions. + * + * @since 1.0.0 + * @since-jetpack 8.8.0 + * + * @return void + */ + private function __construct() { + if ( is_admin() ) { + return; + } + + /** + * Whether the lazy-images module should load. + * + * This filter is not prefixed with jetpack_ to provide a smoother migration + * process from the WordPress Lazy Load plugin. + * + * @package automattic/jetpack-lazy-images + * + * @since 1.0.0 + * @since-jetpack 5.6.0 + * + * @param bool true Whether lazy image loading should occur. + */ + if ( ! apply_filters( 'lazyload_is_enabled', true ) ) { + return; + } + + if ( self::is_amp_request() ) { + return; + } + + add_action( 'wp_head', array( $this, 'setup_filters' ), 9999 ); // We don't really want to modify anything in <head> since it's mostly all metadata. + add_action( 'wp_enqueue_scripts', array( $this, 'enqueue_assets' ) ); + + // Do not lazy load avatar in admin bar. + add_action( 'admin_bar_menu', array( $this, 'remove_filters' ), 0 ); + + add_filter( 'wp_kses_allowed_html', array( $this, 'allow_lazy_attributes' ) ); + add_action( 'wp_head', array( $this, 'add_nojs_fallback' ) ); + } + + /** + * Setup filters. + * + * @since 1.0.0 + * @since-jetpack 5.6.0 + * + * @return void + */ + public function setup_filters() { + add_filter( 'the_content', array( $this, 'add_image_placeholders' ), PHP_INT_MAX ); // Run this later, so other content filters have run, including image_add_wh on WP.com. + add_filter( 'post_thumbnail_html', array( $this, 'add_image_placeholders' ), PHP_INT_MAX ); + add_filter( 'get_avatar', array( $this, 'add_image_placeholders' ), PHP_INT_MAX ); + add_filter( 'widget_text', array( $this, 'add_image_placeholders' ), PHP_INT_MAX ); + add_filter( 'get_image_tag', array( $this, 'add_image_placeholders' ), PHP_INT_MAX ); + add_filter( 'wp_get_attachment_image_attributes', array( __CLASS__, 'process_image_attributes' ), PHP_INT_MAX ); + } + + /** + * Remove filters. + * + * @since 1.0.0 + * @since-jetpack 5.6.0 + * + * @return void + */ + public function remove_filters() { + remove_filter( 'the_content', array( $this, 'add_image_placeholders' ), PHP_INT_MAX ); + remove_filter( 'post_thumbnail_html', array( $this, 'add_image_placeholders' ), PHP_INT_MAX ); + remove_filter( 'get_avatar', array( $this, 'add_image_placeholders' ), PHP_INT_MAX ); + remove_filter( 'widget_text', array( $this, 'add_image_placeholders' ), PHP_INT_MAX ); + remove_filter( 'get_image_tag', array( $this, 'add_image_placeholders' ), PHP_INT_MAX ); + remove_filter( 'wp_get_attachment_image_attributes', array( __CLASS__, 'process_image_attributes' ), PHP_INT_MAX ); + } + + /** + * Ensure that our lazy image attributes are not filtered out of image tags. + * + * @since 1.0.0 + * @since-jetpack 5.6.0 + * + * @param array $allowed_tags The allowed tags and their attributes. + * @return array + */ + public function allow_lazy_attributes( $allowed_tags ) { + if ( ! isset( $allowed_tags['img'] ) ) { + return $allowed_tags; + } + + // But, if images are allowed, ensure that our attributes are allowed! + $img_attributes = array_merge( + $allowed_tags['img'], + array( + 'data-lazy-src' => 1, + 'data-lazy-srcset' => 1, + 'data-lazy-sizes' => 1, + ) + ); + + $allowed_tags['img'] = $img_attributes; + + return $allowed_tags; + } + + /** + * Add image placeholders. + * + * @since 1.0.0 + * @since-jetpack 5.6.0 + * + * @param string $content Content. + * @return string + */ + public function add_image_placeholders( $content ) { + // Don't lazy load for feeds, previews. + if ( is_feed() || is_preview() ) { + return $content; + } + + // Don't lazy-load if the content has already been run through previously. + if ( false !== strpos( $content, 'data-lazy-src' ) ) { + return $content; + } + + // This is a pretty simple regex, but it works. + $content = preg_replace_callback( '#<(img)([^>]+?)(>(.*?)</\\1>|[\/]?>)#si', array( __CLASS__, 'process_image' ), $content ); + + return $content; + } + + /** + * Returns true when a given string of classes contains a class signifying lazy images. + * should not process the image. + * + * @since 1.0.0 + * @since-jetpack 5.9.0 + * + * @param string $classes A string of space-separated classes. + * @return bool + */ + public static function should_skip_image_with_blocked_class( $classes ) { + $blocked_classes = array( + 'skip-lazy', + 'gazette-featured-content-thumbnail', + ); + + /** + * Allow plugins and themes to tell lazy images to skip an image with a given class. + * + * @package automattic/jetpack-lazy-images + * + * @since 1.0.0 + * @since-jetpack 8.7.0 + * + * @param array An array of strings where each string is a class. + */ + $blocked_classes = apply_filters( 'jetpack_lazy_images_blocked_classes', $blocked_classes ); + + if ( ! is_array( $blocked_classes ) || empty( $blocked_classes ) ) { + return false; + } + + foreach ( $blocked_classes as $class ) { + if ( false !== strpos( $classes, $class ) ) { + return true; + } + } + + return false; + } + + /** + * Processes images in content by acting as the preg_replace_callback. + * + * @since 1.0.0 + * @since-jetpack 5.6.0 + * + * @param array $matches Matches. + * + * @return string The image with updated lazy attributes. + */ + public static function process_image( $matches ) { + $old_attributes_str = $matches[2]; + $old_attributes_kses_hair = wp_kses_hair( $old_attributes_str, wp_allowed_protocols() ); + + if ( empty( $old_attributes_kses_hair['src'] ) ) { + return $matches[0]; + } + + $old_attributes = self::flatten_kses_hair_data( $old_attributes_kses_hair ); + + // If we didn't add lazy attributes, just return the original image source. + if ( ! empty( $old_attributes['class'] ) && false !== strpos( $old_attributes['class'], 'jetpack-lazy-image' ) ) { + return $matches[0]; + } + + $new_attributes = self::process_image_attributes( $old_attributes ); + $new_attributes_str = self::build_attributes_string( $new_attributes ); + + return sprintf( '<img %1$s><noscript>%2$s</noscript>', $new_attributes_str, $matches[0] ); + } + + /** + * Given an array of image attributes, updates the `src`, `srcset`, and `sizes` attributes so + * that they load lazily. + * + * @since 1.0.0 + * @since-jetpack 5.7.0 + * + * @param array $attributes Attributes. + * + * @return array The updated image attributes array with lazy load attributes. + */ + public static function process_image_attributes( $attributes ) { + if ( empty( $attributes['src'] ) ) { + return $attributes; + } + + if ( ! empty( $attributes['class'] ) && self::should_skip_image_with_blocked_class( $attributes['class'] ) ) { + return $attributes; + } + + if ( isset( $attributes['data-skip-lazy'] ) ) { + return $attributes; + } + + /** + * Allow plugins and themes to conditionally skip processing an image via its attributes. + * + * @package automattic/jetpack-lazy-images + * + * @since 1.0.0 + * @since-jetpack 5.9.0 + * @deprecated-jetpack 6.5.0 Use jetpack_lazy_images_skip_image_with_attributes instead. + * + * @param bool Default to not skip processing the current image. + * @param array An array of attributes via wp_kses_hair() for the current image. + */ + if ( apply_filters( 'jetpack_lazy_images_skip_image_with_atttributes', false, $attributes ) ) { + return $attributes; + } + + /** + * Allow plugins and themes to conditionally skip processing an image via its attributes. + * + * @package automattic/jetpack-lazy-images + * + * @since 1.0.0 + * @since-jetpack 5.9.0 + * @since-jetpack 6.5.0 Filter name was updated from jetpack_lazy_images_skip_image_with_atttributes to correct typo. + * + * @param bool Default to not skip processing the current image. + * @param array An array of attributes via wp_kses_hair() for the current image. + */ + if ( apply_filters( 'jetpack_lazy_images_skip_image_with_attributes', false, $attributes ) ) { + return $attributes; + } + + $old_attributes = $attributes; + + // Stash srcset and sizes in data attributes. + foreach ( array( 'srcset', 'sizes' ) as $attribute ) { + if ( isset( $old_attributes[ $attribute ] ) ) { + $attributes[ "data-lazy-$attribute" ] = $old_attributes[ $attribute ]; + unset( $attributes[ $attribute ] ); + } + } + + // We set this, adding the query arg so that it doesn't exactly equal the src attribute, so that photon JavaScript + // will hold off on processing this image. + $attributes['data-lazy-src'] = esc_url_raw( add_query_arg( 'is-pending-load', true, $attributes['src'] ) ); + + $attributes['srcset'] = self::get_placeholder_image(); + $attributes['class'] = sprintf( + '%s jetpack-lazy-image', + empty( $old_attributes['class'] ) + ? '' + : $old_attributes['class'] + ); + + /** + * Allow plugins and themes to override the attributes on the image before the content is updated. + * + * One potential use of this filter is for themes that set `height:auto` on the `img` tag. + * With this filter, the theme could get the width and height attributes from the + * $attributes array and then add a style tag that sets those values as well, which could + * minimize reflow as images load. + * + * @package automattic/jetpack-lazy-images + * + * @since 1.0.0 + * @since-jetpack 5.6.0 + * + * @param array An array containing the attributes for the image, where the key is the attribute name + * and the value is the attribute value. + */ + return apply_filters( 'jetpack_lazy_images_new_attributes', $attributes ); + } + + /** + * Adds JavaScript to check if the current browser supports JavaScript as well as some styles to hide lazy + * images when the browser does not support JavaScript. + * + * @since 1.0.0 + * @since-jetpack 5.6.0 + * + * @return void + */ + public function add_nojs_fallback() { + ?> + <style type="text/css"> + /* If html does not have either class, do not show lazy loaded images. */ + html:not( .jetpack-lazy-images-js-enabled ):not( .js ) .jetpack-lazy-image { + display: none; + } + </style> + <script> + document.documentElement.classList.add( + 'jetpack-lazy-images-js-enabled' + ); + </script> + <?php + } + + /** + * Retrieves the placeholder image after running it through the lazyload_images_placeholder_image filter. + * + * @since 1.0.0 + * @since-jetpack 5.6.0 + * + * @return string The placeholder image source. + */ + private static function get_placeholder_image() { + /** + * Allows plugins and themes to modify the placeholder image. + * + * This filter is not prefixed with jetpack_ to provide a smoother migration + * process from the WordPress Lazy Load plugin. + * + * @module lazy-images + * + * @since 1.0.0 + * @since-jetpack 5.6.0 + * @since-jetpack 6.5.0 Default image is now a base64 encoded transparent gif. + * + * @param string The URL to the placeholder image. + */ + return apply_filters( + 'lazyload_images_placeholder_image', + 'data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7' + ); + } + + /** + * Flatter KSES hair data. + * + * @since 1.0.0 + * @since-jetpack 5.6.0 + * + * @param array $attributes Attributes. + * + * @return array + */ + private static function flatten_kses_hair_data( $attributes ) { + $flattened_attributes = array(); + foreach ( $attributes as $name => $attribute ) { + $flattened_attributes[ $name ] = $attribute['value']; + } + return $flattened_attributes; + } + + /** + * Build attributes string. + * + * @since 1.0.0 + * @since-jetpack 5.6.0 + * + * @param array $attributes Attributes. + * + * @return string + */ + private static function build_attributes_string( $attributes ) { + $string = array(); + foreach ( $attributes as $name => $value ) { + if ( '' === $value ) { + $string[] = sprintf( '%s', $name ); + } else { + $string[] = sprintf( '%s="%s"', $name, esc_attr( $value ) ); + } + } + return implode( ' ', $string ); + } + + /** + * Enqueue assets. + * + * @since 1.0.0 + * @since-jetpack 5.6.0 + * + * @return void + */ + public function enqueue_assets() { + Assets::register_script( + 'jetpack-lazy-images-polyfill-intersectionobserver', + '../dist/intersection-observer.js', + __FILE__, + array( + 'nonmin_path' => '../dist/intersection-observer.src.js', + 'in_footer' => true, + ) + ); + Assets::register_script( + 'jetpack-lazy-images', + '../dist/lazy-images.js', + __FILE__, + array( + 'nonmin_path' => 'js/lazy-images.js', + 'dependencies' => array( 'jetpack-lazy-images-polyfill-intersectionobserver' ), + 'in_footer' => true, + ) + ); + Assets::enqueue_script( 'jetpack-lazy-images' ); + wp_localize_script( + 'jetpack-lazy-images', + 'jetpackLazyImagesL10n', + array( + 'loading_warning' => __( 'Images are still loading. Please cancel your print and try again.', 'jetpack-lazy-images' ), + ) + ); + } +} |