How to access Alipay's instant payment function with PHP

<form action="/pay/alipayapi.php" class="tm-panel-small uk-form uk-form-stacked" method="post" target="_blank">                            

  <p class="element" style="margin-top:60px;">                                                             

  </p>                                                                                 

  <p class="uk-form-row">                                                                       

  <p class="uk-form-controls">                                                                     

      <label for="form-username" class="uk-form-label" style="display:inline-block;padding: 0 10px;vertical-align: middle;margin-left:-20px;">订单序号:</label>   

      <input class="uk-form-width-large" type="text" name="WIDout_trade_no" id="out_trade_no" value="<?php echo trim($_GET[&#39;orderid&#39;]);?>" >            

      <br>                                                                              

  </p>                                                                                 

  </p>                                                                                 

  <p class="uk-form-row">                                                                       

  <p class="uk-form-controls">                                                                     

      <label for="form-username" class="uk-form-label" style="display:inline-block;padding: 0 10px;vertical-align: middle;margin-left:-20px;">商品名称:</label>   

      <input class="uk-form-width-large" type="text" name="WIDsubject" value="<?php echo trim($_GET[&#39;orderid&#39;]);?>" >                        

      <br>                                                                              

  </p>                                                                                 

  </p>                                                                                 

  <p class="uk-form-row">                                                                       

  <p class="uk-form-controls">                                                                     

      <label for="form-username" class="uk-form-label" style="display:inline-block;padding: 0 10px;vertical-align: middle;margin-left:-20px;">付款金额:</label>   

      <input class="uk-form-width-large" type="text" name="WIDtotal_fee" value="<?php echo trim($_GET[&#39;amt&#39;]);?>">                          

      <br>                                                                              

  </p>                                                                                 

  </p>                                                                                 

  <p class="uk-form-row">                                                                       

  <p class="uk-form-controls">                                                                     

      <label for="form-username" class="uk-form-label" style="display:inline-block;padding: 0 10px;vertical-align: middle;margin-left:-20px;">商品描述:</label>   

      <input class="uk-form-width-large" type="text" name="WIDbody" value="订单测试支付">                                      

      <br>                                                                              

  </p>                                                                                 

  </p>                                                                                 

 <input type="hidden" name="uid" value="<?php echo $_GET[&#39;uid&#39;];?>">                                                   

 <input type="hidden" name="codes" value="<?php echo $_GET[&#39;code&#39;];?>">                                                 

 <input type="hidden" name="tags" value="<?php echo $_GET[&#39;tag&#39;] ?>">                                                  

  <p class="uk-form-row">                                                                       

   <input class="uk-button uk-button-primary uk-button-large uk-width-1-1" type="submit" class="alisubmit" value ="确认支付">                   

  </p>                                                                                 

 </p>                                                                                 

 </form>

$alipay_config['partner']        = 'xxxxxxxxxxxx';                                 

//收款支付宝账号，以2088开头由16位纯数字组成的字符串，一般情况下收款账号就是签约账号                   

$alipay_config['seller_id']   = $alipay_config['partner'];                               

// MD5密钥，安全检验码，由数字和字母组成的32位字符串，查看地址：https://b.alipay.com/order/pidAndKey.htm         

$alipay_config['key']          = 'xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx';                       

// 服务器异步通知页面路径 需http://格式的完整路径，不能加?id=123这类自定义参数，必须外网可以正常访问           

$alipay_config['notify_url'] = "http://xx.xx.xx.xx/pay/notify_url.php";                          

// 页面跳转同步通知页面路径 需http://格式的完整路径，不能加?id=123这类自定义参数，必须外网可以正常访问          

$alipay_config['return_url'] = "http://xx.xx.xx.xx/pay/return_url.php";                          

//签名方式                                                        

$alipay_config['sign_type']  = strtoupper('MD5');                                    

//字符编码格式 目前支持 gbk 或 utf-8                                           

$alipay_config['input_charset']= strtolower('utf-8');                                   

//ca证书路径地址，用于curl中ssl校验                                            

//请保证cacert.pem文件在当前文件夹目录中                                         

$alipay_config['cacert']  = getcwd().'\\cacert.pem';                                  

//访问模式,根据自己的服务器是否支持ssl访问，若支持请选择https；若不支持请选择http                     

$alipay_config['transport']  = 'http';                                         

// 支付类型 ，无需修改                                                  

$alipay_config['payment_type'] = "1";                                           

// 产品类型，无需修改                                                   

$alipay_config['service'] = "create_direct_pay_by_user";

<?php

/* *

 * 功能：支付宝页面跳转同步通知页面

 * 版本：3.3

 * 日期：2012-07-23

 * 说明：

 * 以下代码只是为了方便商户测试而提供的样例代码，商户可以根据自己网站的需要，按照技术文档编写,并非一定要使用该代码。

 * 该代码仅供学习和研究支付宝接口使用，只是提供一个参考。

 *************************页面功能说明*************************

 * 该页面可在本机电脑测试

 * 可放入HTML等美化页面的代码、商户业务逻辑程序代码

 * 该页面可以使用PHP开发工具调试，也可以使用写文本函数logResult，该函数已被默认关闭，见alipay_notify_class.php中的函数verifyReturn

 require_once("alipay.config.php");

 require_once("lib/alipay_notify.class.php");

 ?>

 <!DOCTYPE HTML>

 <html>

   <head>

     <meta http-equiv="Content-Type" content="text/html; charset=utf-8">

 <?php

 //计算得出通知验证结果

 $alipayNotify = new AlipayNotify($alipay_config);

 $verify_result = $alipayNotify->verifyReturn();

 if($verify_result) {//验证成功

     /////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

     //请在这里加上商户的业务逻辑程序代码

     //——请根据您的业务逻辑来编写程序（以下代码仅作参考）——

   //获取支付宝的通知返回参数，可参考技术文档中页面跳转同步通知参数列表

     //商户订单号^M

     $out_trade_no = $_GET['out_trade_no'];

     //支付宝交易号^M

     $trade_no = $_GET['trade_no'];

     //交易状态

     $trade_status = $_GET['trade_status'];

     $total_fee = $_GET['total_fee'];

     //获取用户返回数据

     $user_info = $_GET['extra_common_param'];

     $user_arr = explode('.',$user_info);

     $uid = $user_arr[0];

     $code = $user_arr[1];

     $tags = $user_arr[2];

   if($_GET['trade_status'] == 'TRADE_FINISHED' || $_GET['trade_status'] == 'TRADE_SUCCESS') {

         $types = "alipay";

         $user_url = "/user_obj/do_orderinfo.php";

         die("<script>;window.location=&#39;{$user_url}?uid={$uid}&code={$code}&tags={$tags}&payAmount={$total_fee}&order={$out_trade_no}&types={$types}&#39;;</script>");

         //判断该笔订单是否在商户网站中已经做过处理

         //如果没有做过处理，根据订单号（out_trade_no）在商户网站的订单系统中查到该笔订单的详细，并执行商户的业务程序

         //如果有做过处理，不执行商户的业务程序

   }

   else {

    echo "trade_status=".$_GET['trade_status'];

   }

 var_dump($verify_result);

     echo "验证成功<br />";

     //——请根据您的业务逻辑来编写程序（以上代码仅作参考）——

     /////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

 }

 else {

   //验证失败

   //如要调试，请看alipay_notify.php页面的verifyReturn函数

   echo "验证失败";

 }

 ?>

     <title>支付宝即时到账交易接口</title>

     </head>

   <body>

   </body>

 </html>