php通过CURL模拟post提交请求

<?php
    header("Content-type:text/html;charset=utf-8");

    class Test{

        public function request_post($url = '', $param = '',$headers = array()){
            if (empty($url) || empty($param) || empty($headers)) {
                return false;
            }
            
            $postUrl    = $url;
            $curlPost   = $param;
            $curlHeader = $headers;
            $ch = curl_init();//初始化curl
            curl_setopt($ch, CURLOPT_URL,$postUrl);//抓取指定网页
            curl_setopt($ch, CURLOPT_HTTPHEADER, $curlHeader);//设置header
            curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);//要求结果为字符串且输出到屏幕上
            curl_setopt($ch, CURLOPT_POST, 1);//post提交方式
            curl_setopt($ch, CURLOPT_POSTFIELDS, $curlPost);
            $data = curl_exec($ch);//运行curl
            curl_close($ch);
            
            return $data;
        }

        public function testAction(){
            $url = 'http://web.zhimabot.com:8080/parsor9/robot';
            $post_data['app_id']        = '51';
            $post_data['client_id']     = '123456';
            $post_data['session_id']    = '1528883027691';
            $post_data['intent_update'] = '';
            $post_data['query']         = '播放刘德华的忘情水';

            $headers = array();
            array_push($headers, "Content-Type: application/json; charset=utf-8","Accept: application/json");
            $post_data = json_encode($post_data,JSON_UNESCAPED_UNICODE);

            $res = $this->request_post($url, $post_data,$headers);       
            return $res; 
        }

    }
    
    
    function fn(){
        $action = new Test();
        $result = $action->testAction();
        var_dump($result);
    }

    fn();
    
?>