在集成paypal时不能收到IPN,该如何解决

在集成paypal时不能收到IPN
1. 采用标准集成的方式，按钮进行支付（已经成功）
2. return 能收到。
3. IPN不能收到。。。但是在卖家账号设置里可以看到ipn已经发出去了。
4. sandbox环境

<form action="https://www.sandbox.paypal.com/cgi-bin/webscr" method="post">
<input type="hidden" name="cmd" value="_xclick" />
<input type="hidden" name="business" value="abc@qq.com" />
<input name="item_name" value="Widget" />
<input name="amount" value="1"/>
<input type="hidden" name="currency_code" value="USD" />
<input type="hidden" name="return" value="http://www.abc.com"> 
<input type="hidden" name="notify_url" value="http://www.abc.com/notify.php">
<input type="submit" name="button" id="button" value="pay now" />
</form>


<?php
//从 PayPal 出读取 POST 信息同时添加变量?cmd? 
$req = 'cmd=_notify-validate'; 
foreach ($_POST as $key => $value) { 
$value = urlencode(stripslashes($value)); 
$req .= "&$key=$value"; 
} 
//建议在此将接受到的信息记录到日志文件中以确认是否收到 IPN 信息 
//将信息 POST 回给 PayPal 进行验证 
$header .= "POST /cgi-bin/webscr HTTP/1.0\r\n"; 
$header .= "Content-Type:application/x-www-form-urlencoded\r\n"; 
$header .= "Content-Length:" . strlen($req) ."\r\n\r\n"; 
//在 Sandbox 情况下，设置： 
$fp = fsockopen('www.sandbox.paypal.com',80,$errno,$errstr,30); 
//$fp = fsockopen ('www.paypal.com', 80, $errno, $errstr, 30); 
//将 POST 变量记录在本地变量中 
//该付款明细所有变量可参考： 
//https://www.paypal.com/IntegrationCenter/ic_ipn-pdt-variable-reference.htm
$item_name = $_POST['item_name']; 
$item_number = $_POST['item_number']; 
$payment_status = $_POST['payment_status']; 
$payment_amount = $_POST['mc_gross']; 
$payment_currency = $_POST['mc_currency']; 
$txn_id = $_POST['txn_id']; 
$receiver_email = $_POST['receiver_email']; 
$payer_email = $_POST['payer_email']; 
//… 
//判断回复 POST 是否创建成功 
if (!$fp) { 
//HTTP 错误 
}else { 
//将回复 POST 信息写入 SOCKET 端口 
fputs ($fp, $header .$req); 
//开始接受 PayPal 对回复 POST 信息的认证信息 
while (!feof($fp)) { 
$res = fgets ($fp, 1024); 
//已经通过认证 
if (strcmp ($res, "VERIFIED") == 0) { 

@$fp = fopen("aaa.txt","w");
  if(!$fp){
  echo "system error";
  exit();
  }else {
  fwrite($fp,"完成");
  fclose($fp);
  }

//检查付款状态 
//检查 txn_id 是否已经处理过 
//检查 receiver_email 是否是您的 PayPal 账户中的 EMAIL 地址 
//检查付款金额和货币单位是否正确 
//处理这次付款，包括写数据库 
}else if (strcmp ($res, "INVALID") == 0) { 
//未通过认证，有可能是编码错误或非法的 POST 
@$fp = fopen("bbb.txt","w");
  if(!$fp){
  echo "system error";
  exit();
  }else {
  fwrite($fp,"有错");
  fclose($fp);
  }


} 
} 
fclose ($fp); 
} 
?>

[解决办法]

PHP code

//session_start();$req = 'cmd=_notify-validate';foreach ($_POST as $key => $value) {$value = urlencode(stripslashes($value));$req .= "&$key=$value";}$url='https://www.paypal.com/cgi-bin/webscr';    $curl_result=$curl_err='';    $ch = curl_init();    curl_setopt($ch, CURLOPT_URL,$url);    curl_setopt($ch, CURLOPT_RETURNTRANSFER,1);    curl_setopt($ch, CURLOPT_POST, 1);    curl_setopt($ch, CURLOPT_POSTFIELDS, $req);    curl_setopt($ch, CURLOPT_HTTPHEADER, array("Content-Type: application/x-www-form-urlencoded", "Content-Length: " . strlen($req)));    curl_setopt($ch, CURLOPT_HEADER , 0);       curl_setopt($ch, CURLOPT_VERBOSE, 1);    curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, FALSE);    curl_setopt($ch, CURLOPT_TIMEOUT, 3000);    $curl_result = @curl_exec($ch);    $curl_err = curl_error($ch);    curl_close($ch);$mc_gross = $_POST['mc_gross'];