<?phpdefine("TOKEN", "weixin");
$wechatObj = new wechatCallbackapiTest();if($_GET['echostr'])
{   //接入操作$wechatObj->valid();
}
else
{$wechatObj->responseMsg();
}class wechatCallbackapiTest
{public function valid(){$echoStr = $_GET["echostr"];//valid signature , optionif($this->checkSignature()){echo $echoStr;exit;}}public function responseMsg(){//get post data, May be due to the different environments$postStr = $GLOBALS["HTTP_RAW_POST_DATA"];//extract post dataif (!empty($postStr)){/* libxml_disable_entity_loader is to prevent XML eXternal Entity Injection,the best way is to check the validity of xml by yourself */libxml_disable_entity_loader(true);$postObj = simplexml_load_string($postStr, 'SimpleXMLElement', LIBXML_NOCDATA);$fromUsername = $postObj->FromUserName;$toUsername = $postObj->ToUserName;$keyword = trim($postObj->Content);$MsgType = trim($postObj->MsgType);$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 $resultStr;}else{echo "Input something...";}}else {echo "";exit;}}private function checkSignature(){// you must define TOKEN by yourselfif (!defined("TOKEN")) {throw new Exception('TOKEN is not defined!');}$signature = $_GET["signature"];$timestamp = $_GET["timestamp"];$nonce = $_GET["nonce"];$token = TOKEN;$tmpArr = array($token, $timestamp, $nonce);// use SORT_STRING rulesort($tmpArr, SORT_STRING);$tmpStr = implode( $tmpArr );$tmpStr = sha1( $tmpStr );if( $tmpStr == $signature ){return true;}else{return false;}}
}?>