Bail early for favicon.ico requests so we don't load WP twice. Props azaozz, sivel. Fixes #3426

git-svn-id: https://develop.svn.wordpress.org/trunk@13205 602fd350-edb4-49c9-b593-d223f7449a82

wp-includes/load.php

@@ -104,6 +104,20 @@ function wp_check_php_mysql_versions() {
 		die( /*WP_I18N_OLD_MYSQL*/'Your PHP installation appears to be missing the MySQL extension which is required by WordPress.'/*/WP_I18N_OLD_MYSQL*/ );
 }
 
+/**
+ * Don't load all of WordPress when handling a favicon.ico request.
+ * Instead, send the headers for a zero-length favicon and bail.
+ *
+ * @since 3.0.0
+ */
+function wp_favicon_request() {
+        if ( '/favicon.ico' == $_SERVER['REQUEST_URI'] ) {
+                header('Content-Type: image/vnd.microsoft.icon');
+                header('Content-Length: 0');
+                exit;
+        }
+}
+
 /**
  * Dies with a maintenance message when conditions are met.
  *

wp-settings.php

@@ -43,6 +43,9 @@ wp_fix_server_vars();
 // Check for the required PHP version and for the MySQL extension or a database drop-in.
 wp_check_php_mysql_versions();
 
+// Check if we have recieved a request due to missing favicon.ico 
+wp_favicon_request();
+
 // Check if we're in maintenance mode.
 wp_maintenance();