How to enable the mini program customer service function

<?php
header(&#39;Content-type:text&#39;);
define("TOKEN", "mytoken");

class Mini extends Controller{
    private $appid = &#39;&#39;;
    private $secret = &#39;&#39;;
    public function check(){     //校验服务器地址URL
        if (isset($_GET[&#39;echostr&#39;])) {
            $this->valid();
        }else{
            $this->responseMsg();
        }
    }
    public function valid()
    {
        $echoStr = $_GET["echostr"];
        if($this->checkSignature()){
            header(&#39;content-type:text&#39;);
            echo $echoStr;
            exit;
        }else{
            echo $echoStr.&#39;+++&#39;.TOKEN;
            exit;
        }
    }
    private function checkSignature()
    {
        $signature = $_GET["signature"];
        $timestamp = $_GET["timestamp"];
        $nonce = $_GET["nonce"];
    
        $token = TOKEN;
        $tmpArr = array($token, $timestamp, $nonce);
        sort($tmpArr, SORT_STRING);
        $tmpStr = implode( $tmpArr );
        $tmpStr = sha1( $tmpStr );
    
        if( $tmpStr == $signature ){
            return true;
        }else{
            return false;
        }
    }
    public function responseMsg()
    {
        $postStr = file_get_contents(&#39;php://input&#39;);//因为我的环境是php7
        if (!empty($postStr) && is_string($postStr)){
            $postArr = json_decode($postStr,true);
            if(!empty($postArr[&#39;MsgType&#39;]) && $postArr[&#39;MsgType&#39;] == &#39;text&#39;){   //文本消息
                $fromUsername = $postArr[&#39;FromUserName&#39;];   //发送者openid
                $toUserName = $postArr[&#39;ToUserName&#39;];       //小程序id
                $textTpl = array(
                    "ToUserName"=>$fromUsername,
                    "FromUserName"=>$toUserName,
                    "CreateTime"=>time(),
                    "MsgType"=>"transfer_customer_service",
                );
                exit(json_encode($textTpl));
            }elseif(!empty($postArr[&#39;MsgType&#39;]) && $postArr[&#39;MsgType&#39;] == &#39;image&#39;){ //图文消息
                $fromUsername = $postArr[&#39;FromUserName&#39;];   //发送者openid
                $toUserName = $postArr[&#39;ToUserName&#39;];       //小程序id
                $textTpl = array(
                    "ToUserName"=>$fromUsername,
                    "FromUserName"=>$toUserName,
                    "CreateTime"=>time(),
                    "MsgType"=>"transfer_customer_service",
                );
                exit(json_encode($textTpl));
            }elseif($postArr[&#39;MsgType&#39;] == &#39;event&#39; && $postArr[&#39;Event&#39;]==&#39;user_enter_tempsession&#39;){ 
                $fromUsername = $postArr[&#39;FromUserName&#39;];  

 　　　　　　　　　　$data = array(
                    　　　　　　　　　　 "touser"=>$fromUsername,
                    　　　　　　　　　 　"msgtype"=>"link",
                    　　　　　　　　　　　　"link"=>[
                        　　　　　　　　　　　　"title"=>&#39;this is title&#39;,
                        　　　　　　　　　　　　"description"=> "Is Really A Happy Day",
                        　　　　　　　　　　　　"url":=>"URL",
                        　　　　　　　　　　　　"thumb_url"=>"THUMB_URL"
                    　　　　　　　　　　　　]
                　　　　　　　　　 　);
　　　　　　　　 　$json = json_encode($data,JSON_UNESCAPED_UNICODE); 
                $access_token = $this->get_accessToken();
                $url = "https://api.weixin.qq.com/cgi-bin/message/custom/send?access_token=".$access_token;
                //将数据返给微信服务器进行转发。
                $this->curl_post($url,$json);
                
            }else{
                exit(&#39;aaa&#39;);
            }
        }else{
            echo "";
            exit;
        }
    }
  
    public function get_accessToken(){
        if(cache(&#39;access_token&#39;)){
            return cache(&#39;access_token&#39;);
        }
        /* 不在有效期，重新发送请求，获取access_token */
        else{
            $url = "https://api.weixin.qq.com/cgi-bin/token?grant_type=client_credential&appid={$this->appid}&secret={$this->secret}";
            $result = curl_get_https($url);
            $res = json_decode($result,true);   //json字符串转数组
            if($res){
                cache(&#39;access_token&#39;,$res[&#39;access_token&#39;],7100);
                return cache(&#39;access_token&#39;);
            }else{
                return &#39;api return error&#39;;
            }
        }
    }
    /**
     * @Author   callmelx
     * @DateTime 2018-10-06
     * @return   [type]     [description]
     */
    public function curl_post($url,$data=&#39;&#39;){
        $curl = curl_init();
        curl_setopt($curl, CURLOPT_URL, $url);
        curl_setopt($curl, CURLOPT_POST, 1); // 发送一个常规的Post请求
        curl_setopt($curl, CURLOPT_SSL_VERIFYPEER, FALSE);
        curl_setopt($curl, CURLOPT_SSL_VERIFYHOST, FALSE);
        if (!empty($data)){
            curl_setopt($curl, CURLOPT_POSTFIELDS,$data);
        }
        curl_setopt($curl, CURLOPT_RETURNTRANSFER, 1);
        //curl_setopt($curl, CURLOPT_HTTPHEADER, $headers );
        $output = curl_exec($curl);
        if (curl_errno($curl)) {
            echo &#39;Errno&#39;.curl_error($curl);//捕抓异常
        }
        curl_close($curl);
        if($output == 0){
            echo &#39;success&#39;;exit;
        }
    }
}