验证微信发送的Token验证

<?php
$signature = $_GET["signature"];
$timestamp = $_GET["timestamp"];
$nonce = $_GET["nonce"];
$echostr = $_GET["echostr"];
$token = "your_token";

$tmpArr = array($token, $timestamp, $nonce);
sort($tmpArr, SORT_STRING);
$tmpStr = implode($tmpArr);
$tmpStr = sha1($tmpStr);

if ($tmpStr === $signature) {
    // 响应验证字符串给微信服务器
    echo $echostr;
    exit;
} else {
    // 验证失败，输出错误消息
    echo "Invalid signature";
    exit;
}