← All changes | jetpack_vendor/automattic/jetpack-post-list/src/class-post-thumbnail.php +112 -0 16.2-beta → 16.3-beta View file →

		@@ -1,0 +1,112 @@
	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	+}