HTTP post contentlength error - httpwebrequest

Question

I have a script sending a multi part mime ie a a soap with attachments. I am using C# httpWebRequest class. I am getting an error that says the content length is required yet I am setting the content length dynamically in my code using webrequest's contentLength property. any ideas why this could be? thanx!
this is the code:
public void sendSOAPoverHttpVoda()
{
try
{
string xmlDoc = this.soapXml;
byte[] bytes;
bytes = Encoding.UTF8.GetBytes(xmlDoc);
long contentSize = bytes.Length;
HttpWebRequest req = (HttpWebRequest)WebRequest.Create(conectionUrl);
req.SendChunked = true;
CredentialCache credentialCacheObj = new CredentialCache();
credentialCacheObj.Add(
new Uri(conectionUrl),
"Basic", new NetworkCredential("dddfff", "dddddd"));
credentialCacheObj.Add(new Uri(conectionUrl), "Digest", new NetworkCredential("dddfff", "dddddd"));
req.Credentials = credentialCacheObj;
req.Method = "POST";
req.ProtocolVersion = HttpVersion.Version11;
req.ContentLength = xmlDoc.Length;
req.ContentType = "multipart/related; boundary=\"----=cellsmart_mm7_SOAP\";type=\"text/xml\";Start=\"</cellsmart_mm7_submit>\"";
req.AllowWriteStreamBuffering = true;
req.Timeout = 20000;
req.Headers.Add("SOAPAction", "");
//req.Connection = "";
if (bytes != null)
{
using (Stream outputStream = req.GetRequestStream())
{
outputStream.Write(bytes, 0, xmlDoc.Length);
}
}
using (HttpWebResponse response = (HttpWebResponse)req.GetResponse())
{
Stream responseStream = response.GetResponseStream();
StreamReader reader = new StreamReader(responseStream);
string responseText = reader.ReadToEnd();
Console.WriteLine("Response received from URI : " + responseText);
Console.ReadLine();
}
Console.ReadLine();
}
catch (Exception ex)
{
Console.WriteLine("Error : " + ex.Message + "\n" + ex.StackTrace);
Console.ReadLine();
}
}
The error/exception i get is COntent length required (411)

Answer 1

You can't use both SendChunked=true and ContentLength. The easiest thing to do would be to use a chunked response and omit the ContentLength. You could also retain the ContentLength and omit the SendChunked if you want though.
In case you're not familiar with it, wikipedia has a nice description of chunking.

Answer 2

You declare contentLength as the length of the byte[] that you send ('bytes') and then you use the length of xmlDoc as the content length - which will give a different length than actual. Then you use the same xmlDoc.Length in outputStream.Write.
Why are you not using bytes.Length in both cases? Or contentLength which you've declared but never used, I believe that is your problem, you are sending xmlDoc.Length (Length of a string) for bytes.Length (length of a byte array converted from a string), so when the file is longer than expected by the sent length, the error returns.
Try this:
public void sendSOAPoverHttpVoda()
{
try
{
string xmlDoc = this.soapXml;
byte[] bytes;
bytes = Encoding.UTF8.GetBytes(xmlDoc);
HttpWebRequest req = (HttpWebRequest)WebRequest.Create(conectionUrl);
req.SendChunked = true;
CredentialCache credentialCacheObj = new CredentialCache();
credentialCacheObj.Add(
new Uri(conectionUrl),
"Basic", new NetworkCredential("dddfff", "dddddd"));
credentialCacheObj.Add(new Uri(conectionUrl), "Digest", new NetworkCredential("dddfff", "dddddd"));
req.Credentials = credentialCacheObj;
req.Method = "POST";
req.ProtocolVersion = HttpVersion.Version11;
req.ContentLength = bytes.Length;
req.ContentType = "multipart/related; boundary=\"----=cellsmart_mm7_SOAP\";type=\"text/xml\";Start=\"</cellsmart_mm7_submit>\"";
req.AllowWriteStreamBuffering = true;
req.Timeout = 20000;
req.Headers.Add("SOAPAction", "");
//req.Connection = "";
if (bytes != null)
{
using (Stream outputStream = req.GetRequestStream())
{
outputStream.Write(bytes, 0, bytes.Length);
}
}
using (HttpWebResponse response = (HttpWebResponse)req.GetResponse())
{
Stream responseStream = response.GetResponseStream();
StreamReader reader = new StreamReader(responseStream);
string responseText = reader.ReadToEnd();
Console.WriteLine("Response received from URI : " + responseText);
Console.ReadLine();
}
Console.ReadLine();
}
catch (Exception ex)
{
Console.WriteLine("Error : " + ex.Message + "\n" + ex.StackTrace);
Console.ReadLine();
}
}