Reputation: 31

'System.Net.ProtocolViolationException' {"You must write ContentLength bytes to the request stream before calling [Begin]GetResponse."}

The following exception is occurring in the public string HttpCall(string NvpRequest) method:

'System.Net.ProtocolViolationException' {"You must write ContentLength bytes to the request stream before calling [Begin]GetResponse."}

It occurs on this line of code

//Retrieve the Response returned from the NVP API call to PayPal.
HttpWebResponse objResponse = (HttpWebResponse)objRequest.GetResponse();

Here is the code:

using System;
using System.Collections;
using System.Collections.Specialized;
using System.IO;
using System.Net;
using System.Text;
using System.Data;
using System.Configuration;
using System.Web;
using WingtipToys;
using WingtipToys.Models;
using System.Collections.Generic;
using System.Linq;

public class NVPAPICaller
{
  //Flag that determines the PayPal environment (live or sandbox)
  private const bool bSandbox = true;
private const string CVV2 = "CVV2";

// Live strings.
private string pEndPointURL = "https://api-3t.paypal.com/nvp";
private string host = "www.paypal.com";

// Sandbox strings.
private string pEndPointURL_SB = "https://api-3t.sandbox.paypal.com/nvp";
private string host_SB = "www.sandbox.paypal.com";

private const string SIGNATURE = "SIGNATURE";
private const string PWD = "PWD";
private const string ACCT = "ACCT";

//Replace <Your API Username> with your API Username
//Replace <Your API Password> with your API Password
//Replace <Your Signature> with your Signature
//
// 4/28/2016 Updated by Mike to test the Paypal API 
// Commented out these three (3) lines below and add new credentials
//
//public string APIUsername = "<Your API Username>";
//private string APIPassword = "<Your API Password>";
//private string APISignature = "<Your Signature>";

public string APIUsername = "[email protected]";
private string APIPassword = "Testing123!";
private string APISignature = "MySignature";

private string Subject = "";
private string BNCode = "PP-ECWizard";


//HttpWebRequest Timeout specified in milliseconds 
private const int Timeout = 15000;
private static readonly string[] SECURED_NVPS = new string[] { ACCT, CVV2, SIGNATURE, PWD };

public void SetCredentials(string Userid, string Pwd, string Signature)
{
    APIUsername = Userid;
    APIPassword = Pwd;
    APISignature = Signature;
}

public bool ShortcutExpressCheckout(string amt, ref string token, ref string retMsg)
{
    if (bSandbox)
    {
      pEndPointURL = pEndPointURL_SB;
      host = host_SB;
    }

    string returnURL = "https://localhost:44300/Checkout/CheckoutReview.aspx";
    string cancelURL = "https://localhost:44300/Checkout/CheckoutCancel.aspx";

    NVPCodec encoder = new NVPCodec();
    encoder["METHOD"] = "SetExpressCheckout";
    encoder["RETURNURL"] = returnURL;
    encoder["CANCELURL"] = cancelURL;
    encoder["BRANDNAME"] = "MyBrandNameDuringTesting";
    encoder["PAYMENTREQUEST_0_AMT"] = amt;
    encoder["PAYMENTREQUEST_0_ITEMAMT"] = amt;
    encoder["PAYMENTREQUEST_0_PAYMENTACTION"] = "Sale";
    encoder["PAYMENTREQUEST_0_CURRENCYCODE"] = "USD";

    // Get the Shopping Cart Products
    using (WingtipToys.Logic.ShoppingCartActions myCartOrders = new WingtipToys.Logic.ShoppingCartActions())
    {
      List<CartItem> myOrderList = myCartOrders.GetCartItems();

      for (int i = 0; i < myOrderList.Count; i++)
      {
        encoder["L_PAYMENTREQUEST_0_NAME" + i] = myOrderList[i].Product.ProductName.ToString();
        encoder["L_PAYMENTREQUEST_0_AMT" + i] = myOrderList[i].Product.UnitPrice.ToString();
        encoder["L_PAYMENTREQUEST_0_QTY" + i] = myOrderList[i].Quantity.ToString();
      }
    }

    string pStrrequestforNvp = encoder.Encode();
    string pStresponsenvp = HttpCall(pStrrequestforNvp);

    NVPCodec decoder = new NVPCodec();
    decoder.Decode(pStresponsenvp);

    string strAck = decoder["ACK"].ToLower();
    if (strAck != null && (strAck == "success" || strAck == "successwithwarning"))
    {
      token = decoder["TOKEN"];
      string ECURL = "https://" + host + "/cgi-bin/webscr?cmd=_express-checkout" + "&token=" + token;
      retMsg = ECURL;
      return true;
    }
    else
    {
      retMsg = "ErrorCode=" + decoder["L_ERRORCODE0"] + "&" +
      "Desc=" + decoder["L_SHORTMESSAGE0"] + "&" +
      "Desc2=" + decoder["L_LONGMESSAGE0"];
      return false;
    }
  }

public bool GetCheckoutDetails(string token, ref string PayerID, ref NVPCodec decoder, ref string retMsg)
{
    if (bSandbox)
    {
      pEndPointURL = pEndPointURL_SB;
    }

    NVPCodec encoder = new NVPCodec();
    encoder["METHOD"] = "GetExpressCheckoutDetails";
    encoder["TOKEN"] = token;

    string pStrrequestforNvp = encoder.Encode();
    string pStresponsenvp = HttpCall(pStrrequestforNvp);

    decoder = new NVPCodec();
    decoder.Decode(pStresponsenvp);

    string strAck = decoder["ACK"].ToLower();
    if (strAck != null && (strAck == "success" || strAck == "successwithwarning"))
    {
      PayerID = decoder["PAYERID"];
      return true;
    }
    else
    {
      retMsg = "ErrorCode=" + decoder["L_ERRORCODE0"] + "&" +
      "Desc=" + decoder["L_SHORTMESSAGE0"] + "&" +
      "Desc2=" + decoder["L_LONGMESSAGE0"];

      return false;
    }
  }

public bool DoCheckoutPayment(string finalPaymentAmount, string token, string PayerID, ref NVPCodec decoder, ref string retMsg)
{
    if (bSandbox)
    {
      pEndPointURL = pEndPointURL_SB;
    }

    NVPCodec encoder = new NVPCodec();
    encoder["METHOD"] = "DoExpressCheckoutPayment";
    encoder["TOKEN"] = token;
    encoder["PAYERID"] = PayerID;
    encoder["PAYMENTREQUEST_0_AMT"] = finalPaymentAmount;
    encoder["PAYMENTREQUEST_0_CURRENCYCODE"] = "USD";
    encoder["PAYMENTREQUEST_0_PAYMENTACTION"] = "Sale";

    string pStrrequestforNvp = encoder.Encode();
    string pStresponsenvp = HttpCall(pStrrequestforNvp);

    decoder = new NVPCodec();
    decoder.Decode(pStresponsenvp);

    string strAck = decoder["ACK"].ToLower();
    if (strAck != null && (strAck == "success" || strAck == "successwithwarning"))
    {
      return true;
    }
    else
    {
      retMsg = "ErrorCode=" + decoder["L_ERRORCODE0"] + "&" +
      "Desc=" + decoder["L_SHORTMESSAGE0"] + "&" +
      "Desc2=" + decoder["L_LONGMESSAGE0"];

      return false;
    }
  }

public string HttpCall(string NvpRequest)
{
    string url = pEndPointURL;

    string strPost = NvpRequest + "&" + buildCredentialsNVPString();
    strPost = strPost + "&BUTTONSOURCE=" + HttpUtility.UrlEncode(BNCode);

    HttpWebRequest objRequest = (HttpWebRequest)WebRequest.Create(url);
    objRequest.Timeout = Timeout;
    objRequest.Method = "POST";
    objRequest.ContentLength = strPost.Length;

    try
    {
      using (StreamWriter myWriter = new StreamWriter(objRequest.GetRequestStream()))
      {
        myWriter.Write(strPost);
      }
    }
    catch (Exception e)
    {
      // Log the exception.
      WingtipToys.Logic.ExceptionUtility.LogException(e, "HttpCall in PayPalFunction.cs");
    }

    //Retrieve the Response returned from the NVP API call to PayPal.
    HttpWebResponse objResponse = (HttpWebResponse)objRequest.GetResponse();
    string result;
    using (StreamReader sr = new StreamReader(objResponse.GetResponseStream()))
    {
      result = sr.ReadToEnd();
    }
    return result;
  }

private string buildCredentialsNVPString()
  {
    NVPCodec codec = new NVPCodec();

    if (!IsEmpty(APIUsername))
      codec["USER"] = APIUsername;

    if (!IsEmpty(APIPassword))
      codec[PWD] = APIPassword;

    if (!IsEmpty(APISignature))
      codec[SIGNATURE] = APISignature;

    if (!IsEmpty(Subject))
      codec["SUBJECT"] = Subject;

    codec["VERSION"] = "88.0";

    return codec.Encode();
  }

public static bool IsEmpty(string s)
  {
    return s == null || s.Trim() == string.Empty;
  }
}

public sealed class NVPCodec : NameValueCollection
{
  private const string AMPERSAND = "&";
  private const string EQUALS = "=";
  private static readonly char[] AMPERSAND_CHAR_ARRAY = AMPERSAND.ToCharArray();
  private static readonly char[] EQUALS_CHAR_ARRAY = EQUALS.ToCharArray();

  public string Encode()
  {
    StringBuilder sb = new StringBuilder();
    bool firstPair = true;
    foreach (string kv in AllKeys)
    {
      string name = HttpUtility.UrlEncode(kv);
      string value = HttpUtility.UrlEncode(this[kv]);
      if (!firstPair)
      {
        sb.Append(AMPERSAND);
      }
      sb.Append(name).Append(EQUALS).Append(value);
      firstPair = false;
    }
    return sb.ToString();
  }

  public void Decode(string nvpstring)
  {
    Clear();
    foreach (string nvp in nvpstring.Split(AMPERSAND_CHAR_ARRAY))
    {
      string[] tokens = nvp.Split(EQUALS_CHAR_ARRAY);
      if (tokens.Length >= 2)
      {
        string name = HttpUtility.UrlDecode(tokens[0]);
        string value = HttpUtility.UrlDecode(tokens[1]);
        Add(name, value);
      }
    }
  }

  public void Add(string name, string value, int index)
  {
    this.Add(GetArrayName(index, name), value);
  }

  public void Remove(string arrayName, int index)
  {
    this.Remove(GetArrayName(index, arrayName));
  }

  public string this[string name, int index]
  {
    get
    {
      return this[GetArrayName(index, name)];
    }
    set
    {
      this[GetArrayName(index, name)] = value;
    }
  }

  private static string GetArrayName(int index, string name)
  {
    if (index < 0)
    {
      throw new ArgumentOutOfRangeException("index", "index cannot be negative : " + index);
    }
    return name + index;
  }

Upvotes: 3

Answers (4)

Arvind Chourasiya

Reputation: 17382

Keeping this code in config file solved my issue

<system.webServer>
    <security>
        <requestFiltering>
            <requestLimits maxAllowedContentLength="104857600" />
        </requestFiltering>
    </security>
</system.webServer>

Upvotes: 0

Sherwin V.

Reputation: 21

I know this is old.. But this is how I did it:

Delete this code or just comment this line

objRequest.ContentLength = byteStr.Length;

And add this code:

ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12;

before creating the objRequest:

HttpWebRequest objRequest = (HttpWebRequest)WebRequest.Create(url);

Paypal Stops supporting SSL3 and tsl as of June 2017

Upvotes: 2

Mike Gledhill

Reputation: 29151

I have a C# helper class, which calls a JSON "POST" web service and returns the response. It gets called many times every day and has always worked fine, until yesterday, when suddenly that error started appearing:

You must write ContentLength bytes to the request stream before calling [Begin]GetResponse.

It's weird, because my code was already setting the ContentLength value, so I couldn't understand why, out of the blue, this error would start happening.

We found our that the Business Objects 4 server which we were calling was reporting strange errors. Restarting this server made this strange error go away.

So, it actually had nothing to do with the ContentLength value at all.

So, if you hit this error and your code does look okay, I'd recommand that you check (or better yet, restart) the server whose web services you're calling.

It might save you a few hours of desperate head-scratching...

Upvotes: 0

Gusman

Reputation: 15151

strPost.Length (the quantity of chars on the string) can be completelly different of the number of bytes used to store the string because the encoding.

To ensure correct sizes first get the binary array for the string and use that as size and write it to the stream:

public string HttpCall(string NvpRequest)
{
    string url = pEndPointURL;

    string strPost = NvpRequest + "&" + buildCredentialsNVPString();
    strPost = strPost + "&BUTTONSOURCE=" + HttpUtility.UrlEncode(BNCode);
    var byteStr = Encoding.UTF8.GetBytes(strPost);

    HttpWebRequest objRequest = (HttpWebRequest)WebRequest.Create(url);
    objRequest.Timeout = Timeout;
    objRequest.Method = "POST";
    objRequest.ContentLength = byteStr.Length;

    try
    {
       using(var str = objRequest.GetRequestStream())
           str.Write(byteStr, 0, byteStr.Length);
    }
    catch (Exception e)
    {
  // Log the exception.
      WingtipToys.Logic.ExceptionUtility.LogException(e, "HttpCall in PayPalFunction.cs");
    }

//Retrieve the Response returned from the NVP API call to PayPal.
    HttpWebResponse objResponse = (HttpWebResponse)objRequest.GetResponse();
    string result;
    using (StreamReader sr = new StreamReader(objResponse.GetResponseStream()))
    {
      result = sr.ReadToEnd();
    }

    return result;
}

Upvotes: 2

&#39;System.Net.ProtocolViolationException&#39; {&quot;You must write ContentLength bytes to the request stream before calling [Begin]GetResponse.&quot;}

Answers (4)

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