Ticket #39695: pluggable.patch

.php

@@ -1176 +1176 @@
         if ( !$is_IIS && PHP_SAPI != 'cgi-fcgi' )
                 status_header($status); // This causes problems on IIS and some FastCGI setups
 
+    /**
+     * http2 enabled servers can push the redirected document immediately to client
+     */
+    wp_maybe_add_preload_headers($location);
+
     header("Location: $location", true, $status);
 
     return true;
 }
 endif;
 
+if ( !function_exists('wp_maybe_add_redirect_preload_headers') ) :
+/**
+ * Checks if redirected asset can be preloaded as document
+ *
+ * @param string $location The path to redirect to.
+ * @return bool Redirect-sanitized URL.
+ **/
+function wp_maybe_add_redirect_preload_headers($location) {
+
+    $link = null;
+
+    /**
+     * Check if this is redirect to the same domain so we can add Link headers
+     */
+    $siteurl = site_url();
+    if ( substr( $location, 0, 1 ) === '/' || substr( $location, 0, strlen( $siteurl ) ) === $siteurl ) {
+
+        $location_parts = parse_url( $location );
+
+        if ( substr($location_parts['path'],-1) === '/' ||
+             substr($location_parts['path'],-4) === '.php' ||
+             substr($location_parts['path'],-5) === '.html' ) {
+
+            $link = $location_parts['path'];
+            if ( isset( $location_parts['fragment'] ) )
+                $link .= $location_parts['fragment'];
+            if ( isset( $location_parts['query'] ) )
+                $link .= '?' . $location_parts['query'];
+        }
+    }
+    $link = apply_filters( 'wp_maybe_add_preload_headers', $link, $location );
+
+    if ( $link )
+        header("Link: <{$link}>; rel=preload; as=document", false);
+}
+endif;
+
 if ( !function_exists('wp_sanitize_redirect') ) :
 /**
  * Sanitizes a URL for use in a redirect.