MVC 3 PayPal IPN響應始終無效

Question

我正在使用該文章與PayPal一起玩（http://www.codeproject.com/Articles/42894/Introduction-to-PayPal-for-C-ASP-NET-developers）。

後，貝寶（沙盒）支付完成後，我回到我的瀏覽與查詢字符串：

tx=9S599242S3646572T&st=Completed&amt=9.00&cc=AUD&cm=Registration+started%3a+2012-03-10+18%3a33%3a27&item_number= 

使用代碼

authToken = WebConfigurationManager.AppSettings["PDTToken"]; 

txToken = Request.QueryString.Get("tx"); 

query = string.Format("cmd=_notify-synch&tx={0}&at={1}", 
         txToken, authToken); 

string url = WebConfigurationManager.AppSettings["PayPalSubmitUrl"]; 
HttpWebRequest req = (HttpWebRequest)WebRequest.Create(url); 

req.Method = "POST"; 
req.ContentType = "application/x-www-form-urlencoded"; 
req.ContentLength = query.Length; 

StreamWriter stOut = new StreamWriter(req.GetRequestStream(), 
         System.Text.Encoding.ASCII); 
stOut.Write(query); 
stOut.Close(); 

StreamReader stIn = new StreamReader(req.GetResponse().GetResponseStream()); 
strResponse = stIn.ReadToEnd(); 
stIn.Close(); 

PayPal的響應與類似的東西：

SUCCESS 
first_name=Firstname 
last_name=Lastname 
payment_status=Completed 
payer_email=firstname%40lastname.com 
payment_gross=50.00 
mc_currency=USD 
custom=Custom+value+you+passed+with+your+HTML+form 
etc. 

好，但（可能基於該ersponse）我想驗證事務s Ø我用下面的代碼（那篇文章所）

string postUrl = ConfigurationManager.AppSettings["PayPalSubmitUrl"]; 
    HttpWebRequest req = (HttpWebRequest)WebRequest.Create(postUrl); 

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

    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(); 

但HttpContext.Current.Request.ContentLength是0，所以我總是得到INVALID響應。難道我做錯了什麼 ？

Answer 1

嘗試以下操作：

1. 檢查您的張貼回PayPal的網址是否正確

2. 更換

   byte[] param = Request.BinaryRead(HttpContext.Current.Request.ContentLength); 
   

   與

   byte[] param = HttpContext.Current.Request.BinaryRead(HttpContext.Current.Request.ContentLength);