C# ContentLength error for Request Stream

I’m trying to get an AWS example (from their website) working, and am getting the following error;

System.Net.ProtocolViolationException: ‘You must write ContentLength
bytes to the request stream before calling [Begin]GetResponse.’

on this line of code;

using (HttpWebResponse response = (HttpWebResponse)request.GetResponse())

in this function;

public static void CheckResponse(HttpWebRequest request)
{
    Console.WriteLine("\n-- CHECK RESPONCE");
    // Get the response and read any body into a string, then display.

    Console.WriteLine(request.ContentLength); //857

    using (HttpWebResponse response = (HttpWebResponse)request.GetResponse())
    {
        if (response.StatusCode == HttpStatusCode.OK)
        {
            Console.WriteLine("\n-- HTTP call succeeded");
            var responseBody = ReadResponseBody(response);
            if (!string.IsNullOrEmpty(responseBody))
            {
                Console.WriteLine("\n-- Response body:");
                Console.WriteLine(responseBody);                        
            }
        }
        else
            Console.WriteLine("\n-- HTTP call failed, status code: {0}", response.StatusCode);
    }
}

request.ContentLength is 857, so am not sure how this error makes any sense. I tried setting the request.ContentLength to 857 but that causes an error.

Below is the function that calls CheckResponse()

public static void InvokeHttpRequest(Uri endpointUri,
                                             string httpMethod,
                                             IDictionary<string, string> headers,
                                             string requestBody)
        {
            try
            {
                var request = ConstructWebRequest(endpointUri, httpMethod, headers);

                if (!string.IsNullOrEmpty(requestBody))
                {
                    var buffer = new byte[8192]; // arbitrary buffer size                        
                    var requestStream = request.GetRequestStream();
                    using (var inputStream = new MemoryStream(Encoding.UTF8.GetBytes(requestBody)))
                    {
                        var bytesRead = 0;
                        while ((bytesRead = inputStream.Read(buffer, 0, buffer.Length)) > 0)
                        {
                            requestStream.Write(buffer, 0, bytesRead);
                        }
                    }
                }
                CheckResponse(request);
            }
            catch (WebException ex)
            {
                Console.WriteLine(ex.ToString());
                using (var response = ex.Response as HttpWebResponse)
                {
                    if (response != null)
                    {
                        var errorMsg = ReadResponseBody(response);
                        Console.WriteLine("\n-- HTTP call failed with exception '{0}', status code '{1}'", errorMsg, response.StatusCode);
                    }
                }
            }
        }

>Solution :

Based on very quick scan of the code – looks like you aren’t flushing the requestStream. Wrap it in using block to ensure it is flushed.

var requestStream = request.GetRequestStream();

should be

using(var requestStream = request.GetRequestStream()) ....

The bytes aren’t necessarily written until the stream is disposed or manually flushed.