위챗 인증 코드

<?php
/*
          http://www.cnblogs.com/txw1958/
    CopyRight 2013 www.doucube.com  All Rights Reserved
*/

    define("TOKEN", "futurelib");
    $wechatObj = new wechatCallbackapiTest();
    if (isset($_GET['echostr'])) {
        $wechatObj->valid();
    }else{
        $wechatObj->responseMsg();
    }

    class wechatCallbackapiTest
    {
        public function valid()
        {
            $echoStr = $_GET["echostr"];
            if($this->checkSignature()){
                header('content-type:text');
                echo $echoStr;
                exit;
            }
        }

        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;
            }
        }

        public function responseMsg()
        {
            $postStr = $GLOBALS["HTTP_RAW_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();
                $textTpl = "<xml>
                                <ToUserName><![CDATA[%s]]></ToUserName>
                                <FromUserName><![CDATA[%s]]></FromUserName>
                                <CreateTime><![CDATA[%s]]></CreateTime>
                                <MsgType><![CDATA[%s]]></MsgType>
                                <Content><![CDATA[%s]]></Content>
                                <FuncFlag>0</FuncFlag>
                            </xml>";
                if($keyword == "?" || $keyword == "？")
                {
                    $msgType = "text";
                    $contentStr = date("Y-m-d H:i:s",time());
                    $resultStr = sprintf($textTpl, $fromUsername, $toUsername, $time, $msgType, $contentStr);
                    echo $resultStr;
                }
                else 
                {
                    $msgType = "text";
                    $contentStr = "        ，      ，          ！！！";
                    $resultStr = sprintf($textTpl, $fromUsername, $toUsername, $time, $msgType, $contentStr);
                    echo $resultStr;
                }
            }else{
                echo "";
                exit;
            }
        }
    }
?>