<?php
//定义一个TOKEN
define(\'TOKEN\',\'g825482785\');
//实例化类
$weobj = new wechatCallbackapiTest();
if(!isset($_POST[\'echostr\']))
{
	$weobj->responseMsg();
}
else
{
	$weobj->valid();
}
$weobj->responseMsg();
//创建一个类
class wechatCallbackapiTest
{
	public $fromUsername = \'\';
	public $toUsername = \'\';
	public $time = \'\';
	public function valid()
	{
		$echostr = $_POST[\'echostr\'];
		if($this->checkSignature())
		{
			echo $echostr;
			exit;
		}
	}

	/*
	 * 检验signature
	 * 涉及PHP函数
	 * 1.sort()一组数据排序
	 * 2.implode()将一个一维数组转换为字符串
	 * 3.sha1()利用美国安全散列算法计算字符串的sha1散列值
	 */
	private function checkSignature()
	{
		$signature = $_POST[\'signature\'];
		$timestamp = $_POST[\'timestamp\'];
		$nonce = $_POST[\'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;
		}
	}

	/**
	 * @author  gf
	 * 接收收据返回数据
	 * 涉及函数
	 * 1.simplexml_load_string()把XML字符串载入对象中
	 * 2.trim()去除字符串两边空白字符
	 * 3.time()获得当前时间的时间戳
	 * 4.strtolower()将字符串转换为小写
	 * 5.sprintf()把格式化的字符串写入变量中
	 */
	public function responseMsg() {
		//---------- 接 收 数 据 ---------- //
		$postStr = $GLOBALS["HTTP_RAW_POST_DATA"]; //获取POST数据
		//用SimpleXML解析POST过来的XML数据
		$postObj = simplexml_load_string($postStr,\'SimpleXMLElement\',LIBXML_NOCDATA);
		$fromUsername = $postObj->FromUserName; //获取发送方帐号（OpenID）
		$toUsername = $postObj->ToUserName; //获取接收方账号
		$keyword = trim($postObj->Content); //获取消息内容
		$type = $postObj->MsgType;
		$time = time(); //获取当前时间戳
		$PicUrl = $postObj->PicUrl;
		$msgId = $postObj->msgId;
		$event = $postObj->Event;

		//判断类型
		if(strtolower($type) == \'event\') {
			//subscribe事件  关注微信号即可触发。微信开发文档有详细说明
			if ($event == \'subscribe\') {
				$msgType = \'text\';
				$content = \'欢迎大家关注我的微信账号！\';
				//text格式的xml
				$textTpl = "<xml>
								<ToUserName><![CDATA[%s]]></ToUserName>
								<FromUserName><![CDATA[%s]]></FromUserName>
								<CreateTime>%s</CreateTime>
								<MsgType><![CDATA[%s]]></MsgType>
								<Content><![CDATA[%s]]></Content>
							</xml>";
				$resultStr = sprintf($textTpl, $fromUsername, $toUsername, $time, $msgType, $content);
				echo $resultStr;
			}
		}
	}
}