微信关注与取消关注事件推送

<?php
//
// 关注/取消关注事件消息
// 微信公众账号关注与取消关注事件消息
//

define("TOKEN", "zhouqi");

$wechatObj = new wechatCallbackapiTest();
if (!isset($_GET['echostr'])) {
    $wechatObj->responseMsg();
}else{
    $wechatObj->valid();
}

class wechatCallbackapiTest
{
    public function valid()
    {
        $echoStr = $_GET["echostr"];
        if($this->checkSignature()){
            echo $echoStr;
            exit;
        }
    }

    private function checkSignature()
    {
        $signature = $_GET["signature"];
        $timestamp = $_GET["timestamp"];
        $nonce = $_GET["nonce"];
        $token = TOKEN;
        $tmpArr = array($token, $timestamp, $nonce);
        sort($tmpArr);
        $tmpStr = implode($tmpArr);
        $tmpStr = sha1($tmpStr);

        if($tmpStr == $signature){
            return true;
        }else{
            return false;
        }
    }

    public function responseMsg()
    {
        $postStr = $GLOBALS["HTTP_RAW_POST_DATA"];
        if (!empty($postStr)){
            $postObj = simplexml_load_string($postStr, 'SimpleXMLElement', LIBXML_NOCDATA);
            $RX_TYPE = trim($postObj->MsgType);

            switch ($RX_TYPE)
            {
                case "event":
                    $result = $this->receiveEvent($postObj);
                    break;
            }
            echo $result;
        }else {
            echo "";
            exit;
        }
    }

    private function receiveEvent($object)
    {
        $content = "";
        switch ($object->Event)
        {
            case "subscribe":   //关注事件
                $content = "欢迎关注周起，么么哒(づ￣ 3￣)づ";
                break;
            case "unsubscribe": //取消关注事件
                $content = "";
                break;
        }
        $result = $this->transmitText($object, $content);
        return $result;
    }

    private function transmitText($object, $content)
    {
        $textTpl = "<xml>
<ToUserName><![CDATA[%s]]></ToUserName>
<FromUserName><![CDATA[%s]]></FromUserName>
<CreateTime>%s</CreateTime>
<MsgType><![CDATA[text]]></MsgType>
<Content><![CDATA[%s]]></Content>
</xml>";
        $result = sprintf($textTpl, $object->FromUserName, $object->ToUserName, time(), $content);
        return $result;
    }
}
?>