The first entry into the WeChat trap. The first tweet on the WeChat official account. The first WeChat official account of China Business News. The first message on the WeChat official account.

<span style="font-family:KaiTi_GB2312;font-size:14px;"><?php
define("TOKEN","weixin");
$weixinObj = new Wechat();
$weixinObj->valid();

class Wechat{
	public function valid(){
		$echoStr = $_GET['echostr'];
		if($this->checkSignature()){
			echo $echoStr;
			exit;
		}
	}
	//校验方法
	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;
		}
	}
}</span>