HttpWebRequest - GetResponse() - WebException ReceiveFailure

Question

I have a WCF service that is running frequent (1000+) outbound connections per minute to external APIs.

My code throws the following exceptions frequently, but not always showing that is is a WebException with the WebException status property being ReceiveFailure

The code that is making the outbound request is the following:

HttpWebRequest request = (HttpWebRequest)WebRequest.Create(paramBuilder.ToString());
request.ServicePoint.ConnectionLeaseTimeout = 0;
request.Method = "GET";
request.Timeout = 33000;    //33 Second Timeout Is By Design
Stream stream = default(Stream);
HttpWebResponse response = default(HttpWebResponse);
try
{

    response = (HttpWebResponse) request.GetResponse();
    stream = response.GetResponseStream();
    reader = new StreamReader(stream,Encoding.UTF8);
    string str = reader.ReadToEnd();
    return str;

}
catch (WebException exception)
{

    //Handle WebException
}
catch (Exception exception)
{
    //Handle Exception
}
finally
{
    if (reader != null)
        reader.Dispose();

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

    if (stream != null)
        stream.Dispose();
}

The exception stack trace shows that the exception is caused from GetResponse().

What could be causing this to happen that I receive an occasional WebException -ReceiveFailure.

I have already reference the MSDN documentation for this status, but that doesn't help me.

Answer 1

Shooting in the dark here...

There is a special condition, while waiting for response: if the system clock is being set automatically by the Windows Time service, or manually, you may experience some unpredictable results.

If you're sending your requests over HTTPS, maybe you're facing a regular timeout that was wrongly thrown as a ReceiveFailure.

Check this article for more information: http://support.microsoft.com/kb/2007873

Answer 2

I have a related problem and I realise a few things while I was searching for a solution.

• WebExceptionStatus enum is not equivalent to http status code that the API you call returned. Instead it is a enum of possible error that may occour during a http call.
• The WebExceptionStatus error code that will be returned when you receive an error (400 to 599) from your API is WebExceptionStatus.ProtocolError aka number 7 as int.
• When you need to get the response body or the real http status code returned from the api, first you need to check if WebException.Status is WebExceptionStatus.ProtocolError . Then you can get the real response from WebExceptionStatus.Response and read its content.
• Sometimes the timeout is handled by the caller (aka your code) so you do not have a response in that case. So you can look if WebException.Status is WebExceptionStatus.Timeout

This is an example:

try
{
    ...
}
catch (WebException webException)
{
    if (webException.Status == WebExceptionStatus.ProtocolError)
    {
        var httpResponse = (HttpWebResponse)webException.Response;
        var responseText = "";
        using (var content = new StreamReader(httpResponse.GetResponseStream()))
        {
            responseText = content.ReadToEnd(); // Get response body as text
        }
        int statusCode = (int)httpResponse.StatusCode; // Get the status code
    }
    else if (webException.Status == WebExceptionStatus.ProtocolError)
    {
       // Timeout handled by your code. You do not have a response here.
    }

    // Handle other webException.Status errors. You do not have a response here.
}