一、简介

微信公众平台可以根据用户发送的信息进行判断，然后给出对应的回复，具有良好的交互性。下文将模拟简单的回复功能，根据这个案例，开发者也可以基本理解微信交互的原理，进行更深层次的开发。

二、思路分析

用户发送过来的文本信息，我们可以提取关键字，通过简单的 if...elseif...else... 实现。

关键代码如下：

如果用户发送"你好"，则回复"hello"，如果用户发送"苏州"，则回复"上有天堂，下有苏杭"，其他信息，则回复你的欢迎词。

三、完整代码

<div class="jb51code">
<pre class="brush:PHP;">
<?php
/**

• wechat php test
  */

//define your token
define("TOKEN","zhuojin");
$wechatObj = new wechatCallbackapiTest();
$wechatObj->responseMsg();
//$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 (!empty($postStr)){

     $postObj = simplexml_load_string($postStr,'SimpleXMLElement',LIBXML_NOCDATA);
    $RX_TYPE = trim($postObj->MsgType);

    switch($RX_TYPE)
    {
      case "text":
        $resultStr = $this->handleText($postObj);
        break;
      case "event":
        $resultStr = $this->handleEvent($postObj);
        break;
      default:
        $resultStr = "Unknow msg type: ".$RX_TYPE;
        break;
    }
    echo $resultStr;
}else {
  echo "";
  exit;
}

}

public function handleText($postObj)
{
$fromUsername = $postObj->FromUserName;
$toUsername = $postObj->ToUserName;
$keyword = trim($postObj->Content);
$time = time();
$textTpl = "

%s 0 "; if(!empty( $keyword )) { $msgType = "text";

  if($keyword=="你好"){
    $contentStr = "hello";
  }elseif($keyword=="苏州"){
    $contentStr = "上有天堂，下有苏杭";
  }else{
    $contentStr = "感谢您关注【卓锦苏州】 微信号：zhuojinsz";
  }
  $resultStr = sprintf($textTpl,$fromUsername,$toUsername,$time,$msgType,$contentStr);
  echo $resultStr;
}else{
  echo "Input something...";
}

}

public function handleEvent($object)
{
$contentStr = "";
switch ($object->Event)
{
case "subscribe":
$contentStr = "感谢您关注【卓锦苏州】"."\n"."微信号：zhuojinsz"."\n"."卓越锦绣，名城苏州，我们为您提供苏州本地生活指南，苏州相关信息查询，做最好的苏州微信平台。"."\n"."目前平台功能如下："."\n"."【1】 查天气，如输入：苏州天气"."\n"."【2】 查公交，如输入：苏州公交178"."\n"."【3】 翻译，如输入：翻译I love you"."\n"."【4】 苏州信息查询，如输入：苏州观前街"."\n"."更多内容，敬请期待...";
break;
default :
$contentStr = "Unknow Event: ".$object->Event;
break;
}
$resultStr = $this->responseText($object,$contentStr);
return $resultStr;
}

public function responseText($object,$content,$flag=0)
{
$textTpl = "

%s %d "; $resultStr = sprintf($textTpl,$object->FromUserName,$object->ToUserName,time(),$flag); return $resultStr; }

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;
}

}
}

?>