<?php
/**
  * wechat php test
  */

//define your token
define("TOKEN", "twgdh");
$wechatObj = new wechatCallbackapiTest();
//当接入成功后，请注销这句话，否则，会反复验证。
//$wechatObj->valid();
//添加响应请求的语句
$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)){
                /* libxml_disable_entity_loader is to prevent XML eXternal Entity Injection,
                   the best way is to check the validity of xml by yourself */
                // 使用simplexml技术对xml进行解析 
                // libxml_disable_entity_loader(true), 是从安全性考虑，为了防止xml外部注入，
                //只对xml内部实体内容进行解析
                libxml_disable_entity_loader(true);
                //加载 postStr 字符串
                  $postObj = simplexml_load_string($postStr, ‘SimpleXMLElement‘, LIBXML_NOCDATA);
                file_put_contents(‘abc.log‘, "\r\n\r\n". $postStr, FILE_APPEND);
                $fromUsername = $postObj->FromUserName;
                file_put_contents(‘abc.log‘, "\r\n\r\n". $fromUsername, FILE_APPEND);
                $toUsername = $postObj->ToUserName;
                file_put_contents(‘abc.log‘, "\r\n\r\n". $toUsername, FILE_APPEND);
                $keyword = trim($postObj->Content);
                $time = time();
                //根据接收到的消息类型，来进行分支处理(switch)
                switch($postObj->MsgType)
                {
                    case ‘event‘:
                        if($postObj->Event == ‘subscribe‘)
                        {
                            $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>";  
                            $contentStr = "欢迎关注leigood微信测试号噢";
                            $resultStr = sprintf($textTpl, $fromUsername, $toUsername, $time, $contentStr);
                            echo $resultStr; 
                        }
                        break;
                }
        }else {
            echo "";
            exit;
        }
    }
        
    private function checkSignature()
    {
        // you must define TOKEN by yourself
        if (!defined("TOKEN")) {
            throw new Exception(‘TOKEN is not defined!‘);
        }
        
        $signature = $_GET["signature"];
        $timestamp = $_GET["timestamp"];
        $nonce = $_GET["nonce"];
                
        $token = TOKEN;
        $tmpArr = array($token, $timestamp, $nonce);
        // use SORT_STRING rule
        sort($tmpArr, SORT_STRING);
        $tmpStr = implode( $tmpArr );
        $tmpStr = sha1( $tmpStr );
        
        if( $tmpStr == $signature ){
            return true;
        }else{
            return false;
        }
    }
}

?>