Introduce a special wp_die handler for XMLRPC requests to ensure we send an XML response.

Props koke for the original patch. See #16748.

git-svn-id: http://svn.automattic.com/wordpress/trunk@17643 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/functions.php

@@ -2854,6 +2854,42 @@ if ( 'rtl' == $text_direction ) : ?>
 	die();
 }
 
+/**
+ * Kill WordPress execution and display XML message with error message.
+ *
+ * This is the handler for wp_die when processing XMLRPC requests.
+ *
+ * @since 3.2.0
+ * @access private
+ *
+ * @param string $message Error message.
+ * @param string $title Error title.
+ * @param string|array $args Optional arguements to control behaviour.
+ */
+function _xmlrpc_wp_die_handler( $message, $title = '', $args = array() ) { 
+	global $wp_xmlrpc_server;
+	$defaults = array( 'response' => 500 );
+
+	$r = wp_parse_args($args, $defaults);
+
+	if ( $wp_xmlrpc_server ) { 
+		$error = new IXR_Error( $r['response'] , $message); 
+		$wp_xmlrpc_server->output( $error->getXml() ); 
+	}
+	die();
+}
+
+/**
+ * Filter to enable special wp_die handler for xmlrpc requests.
+ * 
+ * @since 3.2.0
+ * @access private
+ */
+function _xmlrpc_wp_die_filter() { 
+	return '_xmlrpc_wp_die_handler';
+}
+
+
 /**
  * Retrieve the WordPress home page URL.
  *

xmlrpc.php

@@ -98,6 +98,9 @@ function logIO($io,$msg) {
 if ( isset($HTTP_RAW_POST_DATA) )
 	logIO("I", $HTTP_RAW_POST_DATA);
 
+// Make sure wp_die output is XML
+add_filter( 'wp_die_handler', '_xmlrpc_wp_die_filter' );
+
 // Allow for a plugin to insert a different class to handle requests.
 $wp_xmlrpc_server_class = apply_filters('wp_xmlrpc_server_class', 'wp_xmlrpc_server');
 $wp_xmlrpc_server = new $wp_xmlrpc_server_class;