rand(1,10)

$tyep= $postObj->MsgType;
$textTpl = "
 <xml>
  <ToUserName><![CDATA[%s]]></ToUserName>
  <FromUserName><![CDATA[%s]]></FromUserName>
  <CreateTime>%s</CreateTime>
  <MsgType><![CDATA[text]]></MsgType>
  <Content><![CDATA[%s]]></Content>
  <FuncFlag>0</FuncFlag>
 </xml>";   

 if ($tyep=="image")
 {
  $a=rand(1,3);
   switch ($a)
   {
    case "1";
     $b="健康好人缘，婚姻幸福美满";
     break;
   case "2";
     $b="贵人相助化险为夷的好运纹";
     break;
    default;
     $b="才华横溢好研究，知识丰富事业有成";        
   }

   $resultStr = sprintf($textTpl, $fromUsername, $toUsername, $time,$b);
   echo $resultStr;
 }

<"TOKEN", "weixin");
$wechatObj = new wechatCallbackapiTest();
$wechatObj->responseMsg();

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();
    $tyep= $postObj->MsgType;
    $textTpl = "
       <xml>
       <ToUserName><![CDATA[%s]]></ToUserName>
       <FromUserName><![CDATA[%s]]></FromUserName>
       <CreateTime>%s</CreateTime>
       <MsgType><![CDATA[text]]></MsgType>
       <Content><![CDATA[%s]]></Content>
       <FuncFlag>0</FuncFlag>
       </xml>";   


    if ($tyep=="image")
    {$a=rand(1,3);
     switch ($a)
     {case "1";
     $b="健康好人缘，婚姻幸福美满";
     break;
     case "2";
     $b="贵人相助化险为夷的好运纹";
     break;
     default;
     $b="才华横溢好研究，知识丰富事业有成";        
     }

     $resultStr = sprintf($textTpl, $fromUsername, $toUsername, $time,$b);
     echo $resultStr;
    }

  }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;
  }
 }
}

?>