Question

I have tried everything and I can not figure out why this error happens.

Background:
I have an IPad application, written in MonoTouch and I have a thread that runs in the background, and every 15 seconds I sync data with the server. This works the first few iterations of the thread, but eventually I get the following stack trace.

An exception occured: System.Net.WebException: Error getting response stream (ReadDone4): ServerProtocolViolation ---> System.FormatException: Input string was not in the correct format
  at System.UInt32.Parse (System.String s) [0x00010] in /Developer/MonoTouch/Source/mono/mcs/class/corlib/System/UInt32.cs:405 
  at System.Net.WebConnection.GetResponse (System.Byte[] buffer, Int32 max) [0x000ba] in /Developer/MonoTouch/Source/mono/mcs/class/System/System.Net/WebConnection.cs:565 
  at System.Net.WebConnection.ReadDone (IAsyncResult result) [0x00095] in /Developer/MonoTouch/Source/mono/mcs/class/System/System.Net/WebConnection.cs:446 
  --- End of inner exception stack trace ---
  at System.Net.HttpWebRequest.EndGetResponse (IAsyncResult asyncResult) [0x0005e] in /Developer/MonoTouch/Source/mono/mcs/class/System/System.Net/HttpWebRequest.cs:819 
  at System.Net.HttpWebRequest.GetResponse () [0x0000e] in /Developer/MonoTouch/Source/mono/mcs/class/System/System.Net/HttpWebRequest.cs:827 
  at SyncService.REST.RestClient.Execute[IEnumerable`1] (SyncService.REST.RestRequest request) [0x00079] in /Users/Chris/Compass/SyncService/REST/RestClient.cs:42 

I am talking to an IIS webserver with default configuration.
Here is the method I am calling:

public RestResponse<T> Execute<T>(RestRequest request){
    var restResponse = new RestResponse<T>();
    var serializer = new JavaScriptSerializer();
    var urlPath = _baseUrl + "/" + request.Resource;
    var httpRequest = (HttpWebRequest)HttpWebRequest.Create(new Uri(urlPath));

    httpRequest.Headers = request.Headers;
    Authenticator.Authenticate(httpRequest);

    httpRequest.Method = request.Method.ToString();
    if (request.Method == Method.POST)
        SetPostData(httpRequest, request);

    HttpWebResponse httpResponse = null;
    try{
        httpResponse = (HttpWebResponse) httpRequest.GetResponse();
        var reader = new StreamReader(httpResponse.GetResponseStream());
        var responseString = reader.ReadToEnd();
        reader.Close();
        restResponse.StatusCode = httpResponse.StatusCode;
        restResponse.Headers = httpResponse.Headers;
        restResponse.Data = serializer.Deserialize<T>(responseString);
        restResponse.ResponseStatus = ResponseStatus.Completed;
    } 
    catch(WebException e){

        restResponse.ResponseStatus = ResponseStatus.Error;
        restResponse.ErrorMessage = e.Message;
        restResponse.ErrorException = e;
        var webResponse = (HttpWebResponse) e.Response;
        if (webResponse != null){
            restResponse.StatusCode = webResponse.StatusCode;
            restResponse.Headers = webResponse.Headers;
        }
        if (restResponse.StatusCode != HttpStatusCode.NotModified)
            Console.WriteLine("An exception occured: " + e + "\r\n");
    }catch (Exception ex) {
        restResponse.ResponseStatus = ResponseStatus.Error;
        restResponse.ErrorMessage = ex.Message;
        restResponse.ErrorException = ex;
    }

    if (httpResponse != null) 
        httpResponse.Close();

    return restResponse;
}

Please help. I don’t know what to do. Google shows nothing.

I am able to make 22 successful requests before the error shows up.

EDIT
I have narrowed it down to being a server issue. This is asp.net MVC and the exception only happens when I send a 304 to the client. See Server Code:

private void ServeHttpStatusCode() {
    Response.StatusCode = 304;
    Response.Status = "304 Not Modified";
    Response.StatusDescription = "The resource you are requesting has not been modified";
    Response.ContentType = "application/json";
    Response.Write("{\"Error\":\"The resource you are requesting has not been modified\"}");
    Response.End();
    Response.Close();
}

Answer 1

• Is there a proxy between the client
  and the server?
• Does it always fail after 22 requests?
  The exception indicates that some UInt32 can’t be parsed.
• Do you get exceptions on the server side?