微信公众号开发第一步token验证

<?php    
/**   
  * wechat php test   
  */    
    
//define your token    
define("TOKEN", "weixin");    
$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;    
        }    
    }    
}

注意事项 ：

服务器地址(URL)必须是公网IP或者域名  端口默认80