class-post-list.php
4 weeks ago
class-post-thumbnail.php
3 years ago
rtl.css
9 months ago
style.css
9 months ago
class-post-thumbnail.php
113 lines
| 1 | <?php |
| 2 | /** |
| 3 | * This file contains the Post_Thumbnail class used for finding a suitable thumbnail for a post. |
| 4 | * |
| 5 | * @package automattic/jetpack-post-list |
| 6 | */ |
| 7 | |
| 8 | namespace Automattic\Jetpack\Post_List; |
| 9 | |
| 10 | /** |
| 11 | * The Post_Thumbnail class contains methods to find and return a suitable thumbnail for a post. |
| 12 | */ |
| 13 | class Post_Thumbnail { |
| 14 | /** |
| 15 | * Returns the featured image thumbnail or if no featured image is set, return the first image in the post. If |
| 16 | * neither exists returns the image array with null values. |
| 17 | * |
| 18 | * @param object $post The current post. |
| 19 | * @return array|null The thumbnail image id and URLs |
| 20 | */ |
| 21 | public static function get_post_thumbnail( $post ) { |
| 22 | $image_id = null; |
| 23 | $image_url = null; |
| 24 | $image_alt = null; |
| 25 | $image_thumb = false; |
| 26 | |
| 27 | $post_id = $post->ID; |
| 28 | |
| 29 | // If a featured image exists for the post, use that thumbnail. |
| 30 | if ( has_post_thumbnail( $post_id ) ) { |
| 31 | $image_id = get_post_thumbnail_id( $post_id ); |
| 32 | $image_url = get_the_post_thumbnail_url( $post_id ); |
| 33 | $image_thumb = get_the_post_thumbnail_url( $post_id, array( 50, 50 ) ); |
| 34 | $image_alt = get_post_meta( $image_id, '_wp_attachment_image_alt', true ); |
| 35 | } else { |
| 36 | // If a featured image does not exist look for the first "media library" hosted image on the post. |
| 37 | $attachment_id = self::get_first_image_id_from_post_content( $post->post_content ); |
| 38 | |
| 39 | if ( null !== $attachment_id ) { |
| 40 | $image_id = $attachment_id; |
| 41 | $image_url = wp_get_attachment_image_url( $attachment_id, 'full-size' ); |
| 42 | $image_thumb = wp_get_attachment_image_url( $attachment_id, array( 50, 50 ) ); |
| 43 | $image_alt = get_post_meta( $attachment_id, '_wp_attachment_image_alt', true ); |
| 44 | } |
| 45 | } |
| 46 | |
| 47 | // If no thumbnail is found return null. |
| 48 | if ( false === $image_thumb ) { |
| 49 | return null; |
| 50 | } |
| 51 | |
| 52 | // Escape values just in case. |
| 53 | return array( |
| 54 | 'id' => esc_attr( $image_id ), |
| 55 | 'url' => esc_url( $image_url ), |
| 56 | 'thumb' => esc_url( $image_thumb ), |
| 57 | 'alt' => esc_attr( $image_alt ), |
| 58 | ); |
| 59 | } |
| 60 | |
| 61 | /** |
| 62 | * Looks for the first image in the post content containing a class value of 'wp-image-{$attachment_id}' and |
| 63 | * returns the $attachment_id from that class value. |
| 64 | * |
| 65 | * @param string $post_content The current post's HTML content. |
| 66 | * @return int The image attachment id. |
| 67 | */ |
| 68 | public static function get_first_image_id_from_post_content( $post_content ) { |
| 69 | // If $post_content does not contain a value of substance, return null right away and avoid trying to parse it. |
| 70 | if ( empty( $post_content ) ) { |
| 71 | return null; |
| 72 | } |
| 73 | |
| 74 | $attachment_id = null; |
| 75 | $dom = new \DOMDocument(); |
| 76 | |
| 77 | // libxml_use_internal_errors(true) silences PHP warnings and errors from malformed HTML in loadHTML(). |
| 78 | // you can consult libxml_get_last_error() or libxml_get_errors() to check for errors if needed. |
| 79 | libxml_use_internal_errors( true ); |
| 80 | $dom->loadHTML( $post_content ); |
| 81 | |
| 82 | // Media library images have a class attribute value containing 'wp-image-{$attachment_id}'. |
| 83 | // Use DomXPath to parse the post content and get the first img tag containing 'wp-image-' as a class value. |
| 84 | $class_name = 'wp-image-'; |
| 85 | $dom_x_path = new \DomXPath( $dom ); |
| 86 | $nodes = $dom_x_path->query( "//img[contains(@class, '$class_name')]/@class" ); |
| 87 | |
| 88 | if ( $nodes->length > 0 ) { |
| 89 | // Get the class attribute value of the 1st image node (aka index 0). |
| 90 | $class_value = $nodes[0]->value; |
| 91 | |
| 92 | // Ignore all class attribute values except 'wp-image{$attachment_id}'. |
| 93 | // Regex english translation: Look for a word \b, that does not start or end with a hyphen (?!-), that |
| 94 | // starts with 'wp-image-', and ends with a number of any length \d+. |
| 95 | $class_name_found = preg_match( '/\b(?!-)wp-image-\d+(?!-)\b/', $class_value, $class_value ); |
| 96 | |
| 97 | if ( $class_name_found ) { |
| 98 | // Get the $attachment_id from the end of the class name value. |
| 99 | $attachment_id = str_replace( $class_name, '', $class_value[0] ); |
| 100 | |
| 101 | // If the ID we found is numeric, cast it as an int. Else, make it null. |
| 102 | if ( is_numeric( $attachment_id ) ) { |
| 103 | $attachment_id = (int) $attachment_id; |
| 104 | } else { |
| 105 | $attachment_id = null; |
| 106 | } |
| 107 | } |
| 108 | } |
| 109 | |
| 110 | return $attachment_id; |
| 111 | } |
| 112 | } |
| 113 |