Paypal IPN 无效返回，不知道为什么

Question

这是我的设置，我会尽量保持代码简短。这是一个 ASP.NET MVC4 应用程序

我在这里设置信息：

    @Html.Hidden("cmd", Model.PayPal.Cmd)
@Html.Hidden("business", Model.PayPal.Business)
@Html.Hidden("return", Model.PayPal.Return)
@Html.Hidden("cancel_return", Model.PayPal.CancelUrl)
@Html.Hidden("notify_url", Model.PayPal.NotifyUrl)
@Html.Hidden("currency_code", Model.PayPal.CurrencyCode)
@Html.Hidden("item_name", Model.PayPal.PlanName)
@Html.Hidden("item_number", Model.Id)

@Html.Hidden("src", Model.PayPal.AutoRecurring)
@Html.Hidden("a3", Model.PayPal.Price)
@Html.Hidden("p3", Model.PayPal.Interval)
@Html.Hidden("t3", Model.PayPal.IntervalType)
@Html.Hidden("txn_type", "subscr_signup")
<input type="image" name="submit"
    src="https://www.paypalobjects.com/en_US/i/btn/btn_subscribe_LG.gif"
    alt="PayPal - The safer, easier way to pay online">
<img alt="" border="0" width="1" height="1"
    src="https://www.paypalobjects.com/en_US/i/scr/pixel.gif">

我在控制器中设置变量：

PayPal paypal = new PayPal();
        bool useSanbox = true;

        if (useSanbox)// for test
            paypal.ActionUrl = "https://www.sandbox.paypal.com/cgi-bin/webscr";
        else//real
            paypal.ActionUrl = "https://www.paypal.com/cgi-bin/webscr";

        paypal.Cmd = "_xclick-subscriptions";
        paypal.Business = "david_1355300634_biz@domain.com";
        paypal.CancelUrl = "http://localhost:25914/home/";
        paypal.Return = "http://localhost:25914/home/ipn";
        paypal.NotifyUrl ="http://localhost:25914/home/ipn";
        paypal.AutoRecurring = "1";
        paypal.Price = ctx.SubscriptionPlans.First(x => x.Name == signInModel.SubscritionPlan).Price.ToString();
        paypal.Interval = "1";
        paypal.IntervalType = "M";
        paypal.CurrencyCode = "USD";
        paypal.PlanName = signInModel.SubscritionPlan;
        paypal.Amount = ctx.SubscriptionPlans.First(x => x.Name == signInModel.SubscritionPlan).Price.ToString();

然后我有这个 IPN 控制器操作：

//Answer from PayPal
    public ActionResult IPN()
    {
        var signInModel = Session["SignUp"] as SignUp;
        //Post back to either sandbox or live
        string strSandbox = "https://www.sandbox.paypal.com/cgi-bin/webscr";
        //string strLive = "https://www.paypal.com/cgi-bin/webscr";
        HttpWebRequest req = (HttpWebRequest)WebRequest.Create(strSandbox);

        //Set values for the request back
        req.Method = "POST";
        req.ContentType = "application/x-www-form-urlencoded";
        byte[] param = Request.BinaryRead(this.Request.ContentLength);
        string strRequest = Encoding.ASCII.GetString(param);
        strRequest += "&cmd=_notify-validate";
        req.ContentLength = strRequest.Length;

        //Send the request to PayPal and get the response
        StreamWriter streamOut = new StreamWriter(req.GetRequestStream(), System.Text.Encoding.ASCII);
        streamOut.Write(strRequest);
        streamOut.Close();
        StreamReader streamIn = new StreamReader(req.GetResponse().GetResponseStream());
        string strResponse = streamIn.ReadToEnd();
        streamIn.Close();

        if (strResponse == "VERIFIED")
        {
            //any param from form
            var text = Request.Form["custom"];
            ctx.SignIns.Add(signInModel);
            ctx.SaveChanges();
            //check the payment_status is Completed
            //check that txn_id has not been previously processed
            //check that receiver_email is your Primary PayPal email
            //check that payment_amount/payment_currency are correct
            //process payment
            return View("RegistrationConfirmation", signInModel);
        }
        else if (strResponse == "INVALID")
        {
            //log for manual investigation
            return View("SignUp", signInModel);
        }
        else
        {
            //log response/ipn data for manual investigation
        }
        //change view
        return View("SignUp", signInModel);
    }

让我失望的是我很好地被路由到了贝宝沙箱，我用一个测试用户登录，确认支付金额，然后点击返回网站。返回会命中我的 IPN 操作，但我得到的响应是“无效”。我在这里错过了一个变量还是什么？我对 api 比较陌生。

Answer 1

另外一个，cmd=_notify-validate 应该是需要发送的第一个参数值。

根据官方文档

"验证您的响应是否包含完全相同的 IPN 变量和值 顺序，以 cmd=_notify-validate 开头。”

Answer 2

您正在尝试在本地进行测试，好吧，paypal 不知道本地主机。您必须上传代码并使用实时 url 对其进行测试