New option "Related Meta Keys"

Fixes #172

includes/admin/default-settings.php

@@ -457,6 +457,14 @@ function crp_settings_list() {
 			'options' => '1',
 			'min'     => '1',
 		),
+		'related_meta_keys'      => array(
+			'id'      => 'related_meta_keys',
+			'name'    => esc_html__( 'Related Meta Keys', 'contextual-related-posts' ),
+			'desc'    => esc_html__( 'Enter a comma-separated list of meta keys. Posts that match the same value of the meta key are displayed before the other related posts', 'contextual-related-posts' ),
+			'type'    => 'csv',
+			'options' => '',
+			'size'    => 'large',
+		),
 		'exclude_post_ids'       => array(
 			'id'      => 'exclude_post_ids',
 			'name'    => esc_html__( 'Post/page IDs to exclude', 'contextual-related-posts' ),

includes/class-crp-query.php

@@ -379,6 +379,8 @@ public function prepare_query_args( $args = array() ) {
 				$meta_query['relation'] = apply_filters( 'crp_query_meta_query_relation', 'AND', $args );
 			}
 
+			$args['meta_query'] = $meta_query; // phpcs:ignore WordPress.DB.SlowDBQuery.slow_db_query_meta_query
+
 			// Set post_status.
 			$args['post_status'] = empty( $args['post_status'] ) ? array( 'publish', 'inherit' ) : $args['post_status'];
 
@@ -863,6 +865,40 @@ public function the_posts( $posts, $query ) {
 				shuffle( $posts );
 			}
 
+			// Related posts by meta_key.
+			if ( ! empty( $this->query_args['related_meta_keys'] ) ) {
+				$related_meta_query = array();
+				$related_meta_keys  = wp_parse_list( $this->query_args['related_meta_keys'] );
+				foreach ( $related_meta_keys as $related_meta_key ) {
+					$related_meta_query[] = array(
+						'key'   => $related_meta_key,
+						'value' => (string) get_post_meta( $this->source_post->ID, $related_meta_key, true ),
+					);
+				}
+
+				if ( count( $related_meta_query ) > 1 ) {
+					/**
+					 * Filter the meta_query relation parameter for related posts by meta_key.
+					 *
+					 * @since 3.3.0
+					 *
+					 * @param string  $relation The logical relationship between each inner meta_query array when there is more than one. Default is 'OR'.
+					 */
+					$related_meta_query['relation'] = apply_filters( 'crp_query_related_meta_query_relation', 'OR' );
+				}
+
+				$meta_posts = get_posts(
+					array(
+						'post__not_in' => (array) $this->source_post->ID,
+						'fields'       => $query->get( 'fields' ),
+						'numberposts'  => $query->get( 'posts_per_page' ),
+						'post_type'    => $query->get( 'post_type' ),
+						'meta_query'   => $related_meta_query, // phpcs:ignore WordPress.DB.SlowDBQuery.slow_db_query_meta_query
+					)
+				);
+				$posts      = array_merge( $meta_posts, $posts );
+			}
+
 			// Manual Posts (manual_related - set via the Post Meta) or Include Posts (can be set as a parameter).
 			$post_ids = array();
 

includes/modules/shortcode.php

@@ -28,11 +28,12 @@ function crp_shortcode( $atts, $content = null ) { // phpcs:ignore Generic.CodeA
 		array_merge(
 			$crp_settings,
 			array(
-				'heading'          => 1,
-				'is_shortcode'     => 1,
-				'offset'           => 0,
-				'include_cat_ids'  => '',
-				'include_post_ids' => '',
+				'heading'           => 1,
+				'is_shortcode'      => 1,
+				'offset'            => 0,
+				'include_cat_ids'   => '',
+				'include_post_ids'  => '',
+				'related_meta_keys' => '',
 			)
 		),
 		$atts,
@@ -42,5 +43,3 @@ function crp_shortcode( $atts, $content = null ) { // phpcs:ignore Generic.CodeA
 	return get_crp( $atts );
 }
 add_shortcode( 'crp', 'crp_shortcode' );
-
-

readme.txt

@@ -167,6 +167,7 @@ You can insert the related posts anywhere in your post using the `[crp]` shortco
 
 * Features:
     * Related posts block allows you to set a custom header above the related posts. Leave blank to get the one from the main settings page.
+    * New option "Related Meta Keys" under the List Tuning tab. You can enter a comma-separted list of meta keys. Posts that match the same value of the meta key are displayed before the other related posts.
 
 * Enhancements/modifications:
     * If the number of "Manual related posts" is greater than the number of related posts, then the database query is bypassed drastically improving perfomance