怎样开启小程序客服功能？

<?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