Reuse Connection with HttpWebRequest in C#

Question

I need to make a POST request using .Net.

I can authenticate by GET, and so I’m trying to make a POST request on the same connection to keep my authentication.

The problem is I get a 401 Not Authenticated exception, which implies the connection hasn’t been reused.

HttpWebRequest request = (HttpWebRequest)WebRequest.Create("my-server");
request.Credentials = new NetworkCredential("user", "password");

request.GetResponse().Close();  // Works fine

// Now the request I want to make...

request = (HttpWebRequest)WebRequest.Create("my-server");
request.Credentials = new NetworkCredential("user", "password");

request.Method = "post";

string postData = "param1=1&param2=2";
byte[] data = new ASCIIEncoding().GetBytes(postData);
request.ContentLength = data.Length;
request.ContentType = "application/x-www-form-urlencoded";

using (Stream stream = request.GetRequestStream())
{
    stream.Write(data, 0, data.Length);
    stream.Close();
    request.GetResponse().Close();      // This line gets a 401 Not Authorized error.
}

EDIT: There has been some suggestions that I need to transfer cookies. The following doesn’t work either:

HttpWebRequest request = (HttpWebRequest)WebRequest.Create("my-server");
request.Credentials = new NetworkCredential("user", "password");

var response = (HttpWebResponse)request.GetResponse();

var cookieContainer = new CookieContainer();
foreach (Cookie cookie in response.Cookies)
{
    cookieContainer.Add(cookie);
}

response.Close();

// Now the request I want to make...

request = (HttpWebRequest)WebRequest.Create("my-server");
request.Credentials = new NetworkCredential("user", "password");
request.CookieContainer = cookieContainer;

request.Method = "post";

string postData = "param1=1&param2=2";
byte[] data = new ASCIIEncoding().GetBytes(postData);
request.ContentLength = data.Length;
request.ContentType = "application/x-www-form-urlencoded";

using (Stream stream = request.GetRequestStream())
{
    stream.Write(data, 0, data.Length);
    request.GetResponse().Close();      // This line gets a 401 Not Authorized error.
}

Solution 1

The reason you don't stay logged in is because you don't give the HttpWebRequest a CookieContainer to keep the session id in.

See the following to StackOverflow Q&A's for your possible solution:

C# keep session id over httpwebrequest

Multiple WebRequest in same session

I hope this helped.

Solution 2

Any idea how the authentication is managed on the other end? IE. If it sets a cookie, then you need to make sure you account for that, see this page, and specifically this note:

Note

For security reasons, cookies are disabled by default. If you want to use cookies, use the CookieContainer property to enable cookies.