Https POST from Php to C#

Question

I have to make a post to a third party https url to get data procesed and sent back. And all I have as an example is this:

$signature= foo_string;
$data_to_post = json_dictionary;
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, $base_url);
curl_setopt($ch, CURLOPT_USERPWD, "$user:$password");
curl_setopt($ch, CURLOPT_HTTPAUTH, CURLAUTH_ANY);
curl_setopt($ch, CURLOPT_HEADER, 1);
curl_setopt($ch, CURLOPT_HTTPHEADER,array('Content-Type: application/json'));
curl_setopt($ch, CURLOPT_HTTPHEADER,array("JSON-Signature: $signature"));
curl_setopt($ch, CURLOPT_POST, 1);
curl_setopt($ch, CURLOPT_POSTFIELDS, $data_to_post);
curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
$data = curl_exec($ch);
curl_close($ch);

As we work with ASP .NET C# 2.0, I have to port this, but I get always a not autenticated error.

Here is what I'm doing:

HttpWebRequest q = (HttpWebRequest)WebRequest.Create(Host + ":" + Port);
                ServicePointManager.ServerCertificateValidationCallback = new System.Net.Security.RemoteCertificateValidationCallback(new interhanse().AcceptAllCertifications);                

                q.Method = "POST";
                q.Headers.Add("JSON-Signature:" + GetSignature(data));
                q.ContentType = "application/json";

                q.UseDefaultCredentials = false;
                q.Credentials = new NetworkCredential(user,pwd, Host);

                byte[] buffer = UTF8Encoding.UTF8.GetBytes(data);

                q.ContentLength = data.Length;                

                Stream oStream = q.GetRequestStream();
                StreamWriter oWriter = new StreamWriter(oStream);
                oWriter.Write(buffer);
                oWriter.Close();


                HttpWebResponse reps = q.GetResponse() as HttpWebResponse;

I've read all SO questions I can find about this, but I don't get any improvements. Thanks in advance!

Answer 1

Well, one thing you're doing wrong is assuming that the length in bytes is the same as the length in characters. You should use buffer.Length for the content length. You're also calling StreamWriter.Write with a byte array. You shouldn't do that - you should just use the stream, as you've already done the encoding:

byte[] buffer = Encoding.UTF8.GetBytes(data);

q.ContentLength = buffer.Length;
using (Stream stream = q.GetRequestStream())
{
    stream.Write(buffer, 0, buffer.Length);
}

Now, that won't solve the authentication issue. You may find that just setting PreAuthenticate solves that though:

q.PreAuthenticate = true;

If that doesn't work, I suggest you run WireShark and look at the differences between the request through Curl and the request from .NET.