host = $host;         $this->port = $port;         $this->version = $version;         $this->debug = $debug;     }     /**      * 请求核心方法      * @param $method  回调方法名      * @param $params  参数数组      * @return array   返回结果数组      */     public function request($method, $params=array())     {
          // 检验request信息         if (!is_scalar($method)) {
              throw new \think\Exception('Method name has no scalar value');         }         if (is_array($params)) {
              $params = array_values($params);         } else {
              throw new \think\Exception('Params must be given as array');         }         // 封装请求数据         $request = json_encode(array(             'jsonrpc' => $this->version,             'method' => $method,             'params' => $params,             'id'     => $this->id++         ));         // 是否是debug模式         $this->debug && $this->debug.='***** Request *****'."\n".$request."\n".'***** End Of request *****'."\n\n";         // curl请求         $ch = curl_init();         curl_setopt($ch, CURLOPT_URL, $this->host);         curl_setopt($ch, CURLOPT_PORT, $this->port);         curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);         curl_setopt($ch, CURLOPT_HTTPHEADER, array('Content-Type: application/json'));         curl_setopt($ch, CURLOPT_POST, true);         curl_setopt($ch, CURLOPT_POSTFIELDS, $request);         $ret = curl_exec($ch);         // 输出调试信息         if ($this->debug) {
              echo nl2br(($this->debug));         }         if ($ret !== false) {
              $response = json_decode($ret);             if (isset($response->error)) {
                  //throw new RPCException($formatted->error->message, $formatted->error->code);                 throw new \think\Exception('Request error: '.$response->error);             } else {
                  return $response;             }         } else {
              throw new \think\Exception("Server did not respond: ".$this->host.':'.$this->port);         }     } }