check parameters for send

Protocols/Websocket.php

@@ -215,6 +215,9 @@ class Websocket implements \Workerman\Protocols\ProtocolInterface
      */
     public static function encode($buffer, ConnectionInterface $connection)
     {
+        if (!is_scalar($buffer)) {
+            throw new \Exception("You can't send(" . gettype($buffer) . ") to client, you need to convert it to a string. ");
+        }
         $len = strlen($buffer);
         if (empty($connection->websocketType)) {
             $connection->websocketType = self::BINARY_TYPE_BLOB;