微信公众平台开发关注/取消关注事件例子

用户在关注与取消关注公众号时，微信会把这个事件推送到开发者填写的URL。方便开发者给用户下发欢迎消息或者做帐号的解绑

下面是一个微信公众平台关注和取消关注的实例:

<?php
define("TOKEN", "w3note"); //定义识别码
$wechatObj = new wechatCallbackapiTest(); //实例化wechatCallbackapiTest类
if (!isset($_GET["echostr"])) {
    $wechatObj->responseMsg();
} else {
    $wechatObj->valid();
}
class wechatCallbackapiTest {
    public function valid() {
        $echoStr = $_GET["echostr"];
        if ($this->checkSignature()) {
            echo $echoStr;
            exit;
        }
    }
    public function responseMsg() //执行接收器方法
    {
        $postStr = $GLOBALS["HTTP_RAW_POST_DATA"];
        if (!empty($postStr)) {
            $postObj = simplexml_load_string($postStr, &#39;SimpleXMLElement&#39;, 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 = "欢迎关注网志博客"; //这里是向关注者发送的提示信息
                break;
            case "unsubscribe":
                $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>
       <FuncFlag>0</FuncFlag>
       </xml>";
        $result = sprintf($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;
        }
    }
}
?>

代码相关参数说明：

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)