Multiple calls to web service fails

Question

I designed the following program to stress test a web service I wrote. The problem is, if I attempt to call the web service more than twice, all subsequent calls fail with the following exception:
spawned number 1
Thread number 1 104
spawned number 2
Thread number 2 104
spawned number 3
System.Net.WebException: The operation has timed out
at System.Net.HttpWebRequest.GetRequestStream(TransportContext& context)
at System.Net.HttpWebRequest.GetRequestStream()
at Slam.Work.WebCall(Int32 i) in c:\Users\AM\Documents\Visual Studio 2013\Proje
cts\Slam\Slam\Program.cs:line 75
Exception thrown for 3
System.ArgumentNullException: Value cannot be null.
Parameter name: destination
at System.IO.Stream.CopyTo(Stream destination)
at Slam.Work.WebCall(Int32 i) in c:\Users\AM\Documents\Visual Studio 2013\Proje
cts\Slam\Slam\Program.cs:line 81
Press any key to continue . . .
Here is the program:
using System;
using System.Text;
using System.Threading;
using System.Net;
using System.IO;
namespace Slam
class Program
static void Main(string[] args)
Work w = new Work();
for (int x = 1; x < 4; x++)
int y = x;
w.WebCall(y);
Thread.Sleep(1000);
public class Work
private string username = "*****";
private string password = "*****";
private string url = "https://192.168.1.23:9092/Api/WebI";
public void WebCall(int i)
Console.WriteLine("spawned number " + i);
try
var credentials = string.Join(":", username, password);
var base64String = Convert.ToBase64String(Encoding.UTF8.GetBytes(credentials));
var request = WebRequest.Create(url);
request.Headers.Add(HttpRequestHeader.Authorization, string.Join(" ", "Basic", base64String));
request.Method = WebRequestMethods.Http.Post;
string fileName = @"c:\work\sample.txt";
System.IO.Stream requestStream = null;
using (var fileStream = File.OpenRead(fileName))
request.ContentLength = fileStream.Length;
ServicePointManager.ServerCertificateValidationCallback = (sender, certificate, chain, sslPolicyErrors) => true;
try
requestStream = request.GetRequestStream();
catch (Exception e)
Console.WriteLine(e);
fileStream.CopyTo(requestStream);
var response = request.GetResponse();
Console.WriteLine("Thread number {0} {1}", i, response.ContentLength);
fileStream.Close();
requestStream.Close();
catch (Exception g)
Console.WriteLine("Exception thrown for " + i);
Console.WriteLine(g);
The program which is failing is the client not the service. Can someone please provide me with some direction as to why this always fails on the third call.

Answer 1

Hi Steven,
According to the second exception, the problem may be that the requestStream of the webservice call is null when the 3rd time the WebRequest send request to the webservice. Please debug the code and verify if it's this case. And it's better to tell us more
about the content of the text file and what the webservice does when you send request to it.
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