Methods for developing follow and unfollow events on WeChat public platform, public platform_PHP tutorial

define("TOKEN", "w3note");//Define identification code
$wechatObj = new wechatCallbackapiTest();//Instantiate the wechatCallbackapiTest class

if(!isset($_GET["echostr"])){
$wechatObj->responseMsg();
}else{
$wechatObj->valid();
}
class wechatCallbackapiTest
{
public function valid()
{
         $echoStr = $_GET["echostr"];
If($this->checkSignature()){
             echo $echoStr;
exit;
          }
}
Public function responseMsg()//Execute the receiver method
{
$postStr = $GLOBALS["HTTP_RAW_POST_DATA"];
If (!emptyempty($postStr)){
        $postObj = simplexml_load_string($postStr, 'SimpleXMLElement', LIBXML_NOCDATA);
$RX_TYPE = trim($postObj->MsgType);
switch($RX_TYPE){
case "event":
         $result = $this->receiveEvent($postObj);
        breadk;
        }
echo $result;
}else{
echo "";
exit;
}
}
private function receiveEvent($object){
$content = "";
switch ($postObj->Event){
case "subscribe":
$content = "Welcome to follow the blog";//Here is the prompt message sent to followers
Break;
case "unsubscribe":
$content = "";
Break;
}
$result = $this->transmitText($object,$content);
Return $result;
}
private function transmitText($object,$content){
$textTpl = "
                                                                                                                                                                                                              %s
                                                                                                                    
0
        ";
$result = sprintf($textTpl, $object->FromUserName, $object->$ToUserName, time(), $content);
Return $result;
}
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;
}
}
}

Code related parameter description:

参数	描述
ToUserName	开发者微信号
FromUserName	发送方帐号（一个OpenID）
CreateTime	消息创建时间 （整型）
MsgType	消息类型，event
Event	事件类型，subscribe(订阅)、unsubscribe(取消订阅)

I hope this article will be helpful to everyone’s PHP programming design.