code: protected function http($url, $params, $method = 'GET', $header = [], $multi = false)
      {
          $opts = [
              CURLOPT_TIMEOUT        => 30,
              CURLOPT_RETURNTRANSFER => 1,
              CURLOPT_SSL_VERIFYPEER => false,
              CURLOPT_SSL_VERIFYHOST => false,
              CURLOPT_HTTPHEADER     => $header,
          ];
  
          /* 根据请求类型设置特定参数 */
          switch (strtoupper($method)) {
              case 'GET':
                  $opts[CURLOPT_URL] = $url . '?' . http_build_query($params);
                  break;
              case 'POST':
                  //判断是否传输文件
                  $params                   = $multi ? $params : http_build_query($params);
                  $opts[CURLOPT_URL]        = $url;
                  $opts[CURLOPT_POST]       = 1;
                  $opts[CURLOPT_POSTFIELDS] = $params;
                  break;
              default:
                  throw new \Exception('不支持的请求方式！');
          }
  
          /* 初始化并执行curl请求 */
          $ch = curl_init();
          curl_setopt_array($ch, $opts);
          $data  = curl_exec($ch);
          $error = curl_error($ch);
          curl_close($ch);
          if ($error) {
              throw new \Exception('请求发生错误：' . $error);
          }
  
          return $data;
      }
docs: 发送HTTP请求方法，目前只支持CURL发送请求
  @param  string $url    请求URL
  @param  array  $params 请求参数
  @param  string $method 请求方法GET/POST
  @return array  $data   响应数据