Ticket #36168: get_canonical.diff

wp-includes/link-template.php

@@ -106 +106 @@
 }
 
 /**
+ * Retrieves the canonical URL for current post or post ID.
+ *
+ * @param int|WP_Post $post      Optional. Post ID or post object. Default is the global `$post`.
+ *
+ * @return false|string  The canonical URL or false if the post does not exist or has not been published yet.
+ */
+function get_canonical_url( $post = 0 ) {
+        if ( ! is_object( $post ) ) {
+                $post = get_post( $post );
+        }
+
+        if ( 'publish' !== $post->post_status ) {
+                return false;
+        }
+
+        $canonical_url = get_permalink( $post, false );
+
+        // If we're generating a canonical for the current page, make sure it has pagination if needed.
+        if ( $post->ID === get_queried_object_id() ) {
+                $page = get_query_var( 'page' );
+                if ( $page >= 2 ) {
+                        if ( '' == get_option( 'permalink_structure' ) ) {
+                                $canonical_url = add_query_arg( 'page', $page, $canonical_url );
+                        } else {
+                                $canonical_url = trailingslashit( $canonical_url ) . user_trailingslashit( $page, 'single_paged' );
+                        }
+                }
+
+                $cpage = get_query_var( 'cpage' );
+                if ( $cpage ) {
+                        $canonical_url = get_comments_pagenum_link( $cpage );
+                }
+        }
+
+        /**
+         * Filter the canonical URL.
+         *
+         * @since
+         *
+         * @param string $string  Canonical URL.
+         * @param WP_Post $post   Post object. Default is the global `$post`.
+         */
+        return add_filter( 'get_canonical_url', $canonical_url, $post );
+}
+
+/**
  * Retrieve full permalink for current post or post ID.
  *
  * @since 1.0.0
@@ -3515 +3561 @@
                 return;
         }
 
-        $url = get_permalink( $id );
+        $url = get_canonical_url( $id );
 
-        $page = get_query_var( 'page' );
-        if ( $page >= 2 ) {
-                if ( '' == get_option( 'permalink_structure' ) ) {
-                        $url = add_query_arg( 'page', $page, $url );
-                } else {
-                        $url = trailingslashit( $url ) . user_trailingslashit( $page, 'single_paged' );
-                }
-        }
-
-        $cpage = get_query_var( 'cpage' );
-        if ( $cpage ) {
-                $url = get_comments_pagenum_link( $cpage );
-        }
         echo '<link rel="canonical" href="' . esc_url( $url ) . "\" />\n";
 }