微信公众号服务器验证

<?php
/**
 * wechat php test
 */
//define your token
define("TOKEN", "wechat");
$wechatObj = new wechatCallbackapiTest();
$wechatObj->valid();
class wechatCallbackapiTest {
    public function valid() {
        $echoStr = $_GET["echostr"];
        //valid signature , option
        if ($this->checkSignature()) {
            echo $echoStr;
            exit;
        }
    }
    public function responseMsg() {
        //get post data, May be due to the different environments
        $postStr = $GLOBALS["HTTP_RAW_POST_DATA"];
        //extract post data
        if (!empty($postStr)) {
            $postObj = simplexml_load_string($postStr, 'SimpleXMLElement', LIBXML_NOCDATA);
            $fromUsername = $postObj->FromUserName;
            $toUsername = $postObj->ToUserName;
            $keyword = trim($postObj->Content);
            $time = time();
            $textTpl = "<xml>

                            <ToUserName><![CDATA[%s]]></ToUserName>

                            <FromUserName><![CDATA[%s]]></FromUserName>

                            <CreateTime>%s</CreateTime>

                            <MsgType><![CDATA[%s]]></MsgType>

                            <Content><![CDATA[%s]]></Content>

                            <FuncFlag>0</FuncFlag>

                            </xml>";
            if (!empty($keyword)) {
                $msgType = "text";
                $contentStr = "Welcome to wechat world!";
                $resultStr = sprintf($textTpl, $fromUsername, $toUsername, $time, $msgType, $contentStr);
                echo $resultStr;
            } else {
                echo "Input something...";
            }
        } else {
            echo "";
            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;
        }
    }
}
?>