<?php
//获得参数 signature nonce token timestamp echostr
$nonce = $_GET['nonce'];
$token = 'imooc';
$timestamp = $_GET['timestamp'];
$echostr = $_GET['echostr'];
$signature = $_GET['signature'];
//形成数组，然后按字典序排序
$array = array();
$array = array($nonce, $timestamp, $token);
sort($array);
//拼接成字符串,sha1加密 ，然后与signature进行校验
$str = sha1( implode( $array ) );
if( $str == $signature && $echostr ){
//第一次接入weixin api接口的时候
echo $echostr;
exit;
}