Ticket #34292: 34292.5.diff

src/wp-admin/includes/admin-filters.php

@@ -43 +43 @@
 add_action( 'admin_head', 'wp_site_icon'             );
 add_action( 'admin_head', '_ipad_meta'               );
 
+// Prerendering.
+add_filter( 'admin_head', 'wp_browser_hints' );
+
 add_action( 'admin_print_scripts-post.php',     'wp_page_reload_on_back_button_js' );
 add_action( 'admin_print_scripts-post-new.php', 'wp_page_reload_on_back_button_js' );
 

src/wp-includes/default-filters.php

@@ -235 +235 @@
 add_action( 'wp_head',             'wp_print_head_scripts',            9    );
 add_action( 'wp_head',             'wp_generator'                           );
 add_action( 'wp_head',             'rel_canonical'                          );
+add_action( 'wp_head',             'wp_browser_hints'                       );
 add_action( 'wp_head',             'wp_shortlink_wp_head',            10, 0 );
 add_action( 'wp_head',             'wp_site_icon',                    99    );
 add_action( 'wp_footer',           'wp_print_footer_scripts',         20    );

src/wp-includes/general-template.php

@@ -2790 +2790 @@
 }
 
 /**
+ * Makes sure browser hint array has unique values.
+ *
+ * @since 4.6.0
+ *
+ * @param array $urls Array of browser hints.
+ */
+function unique_browser_hints( $urls ) {
+        $seen = array();
+        foreach( $urls as $url ) {
+                if ( ! in_array( $url, $seen ) ) {
+                        array_push( $seen, $url );
+                }
+        }
+        return $seen;
+}
+
+/**
+ * Prints out brower hints for dns-prefetch, prerender, preconnect, etc.
+ *
+ * @since 4.6.0
+ */
+function wp_browser_hints() {
+
+        $urls = array(
+                array( 'preconnect', 's.w.org' ),
+        );
+
+        $enqueued_hosts = wp_hint_scripts_styles();
+        $urls           = array_merge( $urls, $enqueued_hosts );
+
+        if ( is_admin() ) {
+                $admin_urls = wp_admin_hints();
+                $urls       = array_merge( $urls, $admin_urls );
+        }
+
+        /**
+         * Filters domains and urls for browser hints.
+         *
+         * @since 4.6.0
+         *
+         * @param array $urls URL's to print for browser hints.
+         */
+        $urls = apply_filters( 'browser_hints', $urls );
+
+        $urls = unique_browser_hints( $urls );
+
+        foreach ( $urls as $url ) {
+                if ( $url[0] === 'dns-prefetch' || $url[0] === 'preconnect' ) {
+                        $url[1] = esc_url( untrailingslashit( $url[1] ), array( 'http', 'https' ) );
+                } else {
+                        $url[1] = esc_url( $url[1], array( 'http', 'https' ) );
+                }
+                printf( "<link rel='%s' href='%s'>\r\n", $url[0], $url[1] );
+        }
+}
+
+/**
+ * Adds browsers hints for common wp-admin scripts and styles.
+ *
+ * @since 4.6.0
+ */
+function wp_admin_hints() {
+
+        $hints = array();
+
+        $screen = get_current_screen();
+
+        if ( $screen->id === 'edit-post' ) {
+
+                $edit_hints = array(
+                        array( 'prefetch', admin_url( 'css/edit.css' ) ),
+                        array( 'prefetch', includes_url( 'js/tinymce/tinymce.min.js' ) ),
+                );
+
+                $hints = array_merge( $hints, $edit_hints );
+
+        } else if ( $screen->id === 'users' ) {
+
+                $users_hints = array(
+                        array( 'prefetch', admin_url( 'js/user-profile.js' ) ),
+                );
+
+                $hints = array_merge( $hints, $users_hints );
+        }
+
+        /**
+         * Filters which admin styles and scripts will be hinted.
+         *
+         * @since 4.6.0
+         *
+         * @param array $hints Admin URL's to hint.
+         */
+        $hints = apply_filters( 'admin_browser_hints', $hints );
+
+        return $hints;
+}
+
+/**
+ * Adds dns-prefetch for all scripts and styles enqueued from external hosts.
+ *
+ * @since 4.6.0
+ */
+function wp_hint_scripts_styles() {
+        global $wp_scripts, $wp_styles;
+
+        $unique_hosts = array();
+
+        if ( is_object( $wp_scripts ) && ! empty( $wp_scripts->registered ) ) {
+                foreach ( $wp_scripts->registered as $registered_script ) {
+                        $this_host = parse_url( $registered_script->src, PHP_URL_HOST );
+                        if ( ! in_array( $this_host, $unique_hosts ) && ! empty( $this_host ) && $this_host !== $_SERVER['SERVER_NAME'] ) {
+                                $unique_hosts[] = $this_host;
+                        }
+                }
+        }
+
+        if ( is_object( $wp_styles ) && ! empty( $wp_styles->registered ) ) {
+                foreach ( $wp_styles->registered as $registered_style ) {
+                        $this_host = parse_url( $registered_style->src, PHP_URL_HOST );
+                        if ( ! in_array( $this_host, $unique_hosts ) && ! empty( $this_host ) && $this_host !== $_SERVER['SERVER_NAME'] ) {
+                                $unique_hosts[] = $this_host;
+                        }
+                }
+        }
+
+        $unique_hosts = array_map( 'add_prefetch_attr', $unique_hosts );
+        return $unique_hosts;
+}
+
+/**
+ * Adds dns-prefetch to hosts of scripts and styles.
+ *
+ * @since 4.6.0
+ *
+ * @param array $hosts A hostname.
+ */
+function add_prefetch_attr( $host ) {
+        $host = array( 'dns-prefetch', $host );
+        return $host;
+}
+
+/**
  * Whether the user should have a WYSIWIG editor.
  *
  * Checks that the user requires a WYSIWIG editor and that the editor is

tests/phpunit/tests/general/template.php

@@ -387 +387 @@
                 $actual = get_the_modified_time( $d, $post_id );
                 $this->assertEquals( $expected, $actual );
         }
+
+        /**
+         * @ticket 34292
+         */
+        function test_wp_dns_prefetch() {
+                $preexpected = "<link rel='preconnect' href='http://s.w.org'>\r\n";
+
+                $this->assertEquals( $preexpected, get_echo( 'wp_browser_hints' ) );
+
+                add_filter( 'browser_hints', array( $this, '_add_dns_prefetch_domains' ) );
+
+                $expected = "<link rel='preconnect' href='http://s.w.org'>\r\n" .
+                            "<link rel='dns-prefetch' href='http://wordpress.org'>\r\n" .
+                            "<link rel='dns-prefetch' href='https://google.com'>\r\n" .
+                            "<link rel='dns-prefetch' href='//make.wordpress.org'>\r\n";
+
+                $this->assertEquals( $expected, get_echo( 'wp_browser_hints' ) );
+        }
+
+        function _add_dns_prefetch_domains( $hints ) {
+                $hints[] = array( 'dns-prefetch', 'http://wordpress.org' );
+                $hints[] = array( 'dns-prefetch', 'https://google.com' );
+                $hints[] = array( 'dns-prefetch', '//make.wordpress.org' );
+
+                return $hints;
+        }
+
+        /**
+         * @ticket 34292
+         */
+        function test_wp_prerender() {
+                $preexpected = "<link rel='preconnect' href='http://s.w.org'>\r\n";
+
+                $this->assertEquals( $preexpected, get_echo( 'wp_browser_hints' ) );
+
+                add_filter( 'browser_hints', array( $this, '_add_prerender_urls' ) );
+
+                $expected = "<link rel='preconnect' href='http://s.w.org'>\r\n" .
+                            "<link rel='prerender' href='https://make.wordpress.org/great-again'>\r\n" .
+                            "<link rel='prerender' href='http://jobs.wordpress.net'>\r\n" .
+                            "<link rel='prerender' href='//core.trac.wordpress.org'>\r\n";
+
+                $this->assertEquals( $expected, get_echo( 'wp_browser_hints' ) );
+        }
+
+        function _add_prerender_urls( $hints ) {
+                $hints[] = array( 'prerender', 'https://make.wordpress.org/great-again' );
+                $hints[] = array( 'prerender', 'http://jobs.wordpress.net' );
+                $hints[] = array( 'prerender', '//core.trac.wordpress.org' );
+
+                return $hints;
+        }
 }