Request doesn't wait for response in .net

Question

I have a windows service which is uploading files to the other website which is processing them. The problem is that with small files it's working fine and it's getting response from there, but with large files (about 6 minute to process) it leaves forever in a waiting mode.

Here is the part of external website post method code:

try
{
  ...
  LogResults();
  return string.Empty;
}
catch (Exception e)
{
  return e.Message;
}

The problem is that I can see logs even for large files, so it means that website always returning value, but for large files my windows service doesn't wait for them.

And here is the code from windows service

var valuesp = new NameValueCollection
{
     { "AccountId", datafeed.AccountId }
};

byte[] resultp = UploadHelper.UploadFiles(url, uploadFiles, valuesp);
response = Encoding.Default.GetString(resultp);

UploadFiles method returns value for small files, but waiting forever for large ones.

Here is complete code of UploadFiles

public static byte[] UploadFiles(string address, IEnumerable<UploadFile> files, NameValueCollection values)
{
    var request = WebRequest.Create(address);
    request.Timeout = System.Threading.Timeout.Infinite; //3600000; // 60 minutes
    request.Method = "POST";
    var boundary = "---------------------------" +
                   DateTime.Now.Ticks.ToString("x", NumberFormatInfo.InvariantInfo);
    request.ContentType = "multipart/form-data; boundary=" + boundary;
    boundary = "--" + boundary;

    using (var requestStream = request.GetRequestStream())
    {
        // Write the values
        if (values != null)
        {
            foreach (string name in values.Keys)
            {
                var buffer = Encoding.ASCII.GetBytes(boundary + Environment.NewLine);
                requestStream.Write(buffer, 0, buffer.Length);
                buffer =
                    Encoding.ASCII.GetBytes(string.Format("Content-Disposition: form-data; name=\"{0}\"{1}{1}", name,
                                                          Environment.NewLine));
                requestStream.Write(buffer, 0, buffer.Length);
                buffer = Encoding.UTF8.GetBytes(values[name] + Environment.NewLine);
                requestStream.Write(buffer, 0, buffer.Length);
            }
        }

        // Write the files
        if (files != null)
        {
            foreach (var file in files)
            {
                var buffer = Encoding.ASCII.GetBytes(boundary + Environment.NewLine);
                requestStream.Write(buffer, 0, buffer.Length);
                buffer =
                    Encoding.UTF8.GetBytes(
                        string.Format("Content-Disposition: form-data; name=\"{0}\"; filename=\"{1}\"{2}", file.Name,
                                      file.Filename, Environment.NewLine));
                requestStream.Write(buffer, 0, buffer.Length);
                buffer =
                    Encoding.ASCII.GetBytes(string.Format("Content-Type: {0}{1}{1}", file.ContentType,
                                                          Environment.NewLine));
                requestStream.Write(buffer, 0, buffer.Length);
                requestStream.Write(file.Stream, 0, file.Stream.Length);
                buffer = Encoding.ASCII.GetBytes(Environment.NewLine);
                requestStream.Write(buffer, 0, buffer.Length);
            }
        }

        var boundaryBuffer = Encoding.ASCII.GetBytes(boundary + "--");
        requestStream.Write(boundaryBuffer, 0, boundaryBuffer.Length);
    }

    using (var response = request.GetResponse())
    using (var responseStream = response.GetResponseStream())
    using (var stream = new MemoryStream())
    {
        responseStream.CopyTo(stream);
        return stream.ToArray();
    }
}

What I'm doing wrong here?

EDIT: Locally it's working even for 7-8 minutes processing. But in live environment doesn't. Can it be related with main app IIS settings? Can it be related with windows service server settings?

EDIT 2: Remote server web.config httpRuntime settings

<httpRuntime enableVersionHeader="false" maxRequestLength="300000" executionTimeout="12000" targetFramework="4.5" />

Answer 1

The problem was with Azure Load Balancer, which has Idle Timeout set to 4 minutes by default. The new post of Windows Azure blog says that this timeout is now configurable to the value between 4-30 minutes

http://azure.microsoft.com/blog/2014/08/14/new-configurable-idle-timeout-for-azure-load-balancer/

However, the problem was solved with sending additional KeepAlive bytes via TCP, which told Load Balancer to not kill requests.

HttpWebRequest request = (HttpWebRequest)WebRequest.Create(address);
...
request.Proxy = null;
request.ServicePoint.SetTcpKeepAlive(true, 30000, 5000); //after 30 seconds, each 5 second

Setting Proxy to null (not using proxy) is mandatory action here, because otherwise proxy will not pass tcp bytes to the server.

Answer 2

Upload your files with a method that comply with RFC1867

See this

And then :

 UploadFile[] files = new UploadFile[]
{
new UploadFile(fileName1),
new UploadFile(fileName2)
};

NameValueCollection form = new NameValueCollection();

form["name1"] = "value1";
form["name2"] = "xyzzy";

string response = UploadHelper.Upload(url, files, form);

That's all folks!

EDIT :

I use the method above to upload files with over 100MB in size, I don't use ASP at all, it works just perfect!

Answer 3

I had a similar issue where upload would work locally but timeout on server. There are 2 things at play here - I'm assuming you're talking about IIS7+. If not, let me know and I'll gladly delete my answer.

So first, there's ASP.NET which looks at this setting (under system.web):

<!-- maxRequestLength is in KB - 10 MB here. This is needed by ASP.NET. Must match with maxAllowedContentLength under system.webserver/security/requestLimits -->
<httpRuntime targetFramework="4.5" maxRequestLength="1048576" />

Then there's IIS:

<system.webServer>
    <security>
        <requestFiltering>
            <!-- maxAllowedContentLength in bytes - 10MB -->
            <requestLimits maxAllowedContentLength="10485760" />
        </requestFiltering>
    </security>
<system.webServer>

You need both of these settings to be present and the limit to match for things to work. Notice that one is in KB and the other one is in bytes.

Answer 4

Maybe it is caused by the IIS upload limit? In IIS7 the standard value is 30MB. See MSDN

EDIT1: Please be aware that if you are uploading multiple files in 1 request the size adds up.

EDIT2: In all MS examples there is always only one Stream.Write(). In MSDN it is stated: After the Stream object has been returned, you can send data with the HttpWebRequest by using the Stream.Write method. My interpretation of this sentence would be that you should call Write() only once. Put all data you want to send into the buffer and call the Write() afterwards.

Answer 5

Have you checked the IIS file size limit on the remote server? It defaults to 30MB, so if the files you are trying to upload are larger than that, it will fail. here's how to change the upload limit (IIS7): http://www.web-site-scripts.com/knowledge-base/article/AA-00696/0/Increasing-maximum-allowed-size-for-uploads-on-IIS7.html

Answer 6

You can achieve this task with AsyncCallback technique.

Whats AsyncCallback?

When the async method finish the processing, AsyncCallback method is automatically called, where post processing stmts can be executed. With this technique there is no need to poll or wait for the async thread to complete.

you can find more details from this link

AsynCallback

Answer 7

you should change this executionTimeout="12000" to executionTimeout="360000" wich means changing execution timeout from 2 minutes to 6 minutes.