if(isset($_GET["echostr"])){
    $signature = $_GET["signature"];
  	$timestamp = $_GET["timestamp"];
  	$nonce     = $_GET["nonce"]; 
    //验证时会传递这个信息
  	$echostr   = $_GET["echostr"];

  	$token = "zhuangzi";
  	$array = array($token, $timestamp, $nonce); 
    //放到一个数组里
  	sort($array, SORT_STRING);
     // 将三人参数进行字典排序
  	$str = implode($array);
     // 将三个参数拼接成一个字符串
  	$str = sha1($str); 
    // 进行 sha1加密
  	if($signature == $str){
  		echo $echostr;
  		exit();
  	}
  	else{
  		return false;
  	}
}
else{
    $postStr = $GLOBALS["HTTP_RAW_POST_DATA"];
    //解析post来的XML为一个对象$postObj
    $postObj      = simplexml_load_string($postStr,
     'SimpleXMLElement', LIBXML_NOCDATA);
      $fromUsername = $postObj->FromUserName;
       //请求消息的用户
      $toUsername   = $postObj->ToUserName; 
      //"我"的公众号id
      $content      = trim($postObj->Content);
       //消息内容
      $MsgType      = trim($postObj->MsgType);
      $textTpl = "<xml>
            <ToUserName><![CDATA[%s]]></ToUserName>
            <FromUserName><![CDATA[%s]]></FromUserName>
            <CreateTime>%s</CreateTime>
            <MsgType><![CDATA[%s]]></MsgType>
            <Content><![CDATA[%s]]></Content>
            </xml>";
      if($MsgType == "text"){
        $ret  = file_put_contents("1.txt", $content);
        //发送消息到 微信 begin
        $contentStr = $content;
        $time = time();
        $resultStr = sprintf($textTpl, $fromUsername, 
          $toUsername, $time, $MsgType, $contentStr);
        echo $resultStr;
        //发送消息到 微信 end
      }
      elseif($MsgType == "image"){
        $picurl = trim($postObj->PicUrl);
        $file = file_get_contents($picurl);
        $path = time().".jpg";
        $ret  = file_put_contents($path, $file);
      }
      
}