按照官网的一直token验证失败

在echo $_GET["echostr"];前加上header('content-type:text');这一句 就验证成功了。

const TOKEN = 'anbaojia';

function checkSignature()

{

$signature = $_GET["signature"];

$timestamp = $_GET["timestamp"];

$nonce = $_GET["nonce"];

$token = self::TOKEN;

$tmpArr = array($token, $timestamp, $nonce);

sort($tmpArr, SORT_STRING);

$tmpStr = implode( $tmpArr );

$tmpStr = sha1( $tmpStr );

if( $tmpStr == $signature ){

           header('content-type:text');

            echo $_GET["echostr"];

}else{

            return false;

}

}