<?php/** * wechat php test * update time: 20141008 *///define your tokendefine("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 = $GLOBALS["HTTP_RAW_POST_DATA"];  //extract post data if (!emptyempty($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(!emptyempty( $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, SORT_STRING);$tmpStr = implode( $tmpArr );$tmpStr = sha1( $tmpStr );if( $tmpStr == $signature ){return true;}else{return false;}}}?>