<?php
/**
 * wechat php test
 * update time: 20141008
 */
//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 = $GLOBALS["HTTP_RAW_POST_DATA"];
  //extract post data
 if (!emptyempty($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;
}
}
}
?>