Question

Where in my C# code do I need to put the code for setting cookies? Firefox shows three cookies when I’m logged in to the system.

Login page

system.local/interface/Login.php

POST /interface/Login.php HTTP/1.1
Host: system.local
User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:14.0) Gecko/20100101 Firefox/14.0.1
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Language: de-de,de;q=0.8,en-us;q=0.5,en;q=0.3
Accept-Encoding: gzip, deflate
Connection: keep-alive
Referer: http://system.local/interface/Login.php
Cookie: language=en_US.UTF-8; StationID=06ae3ed4d72a33dd951572df84a13725
Content-Type: application/x-www-form-urlencoded
Content-Length: 71
user_name=user&password=password123456&language=en&action%3Asubmit=Submit

GET response from index.php when logged in

http://system.local/interface/index.php

GET /interface/index.php HTTP/1.1
Host: system.local
User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:14.0) Gecko/20100101 Firefox/14.0.1
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Language: de-de,de;q=0.8,en-us;q=0.5,en;q=0.3
Accept-Encoding: gzip, deflate
Connection: keep-alive
Referer: system.local/interface/Login.php  
Cookie: language=en_US.UTF-8; StationID=06ae3ed4d72a33dd951572df84a13725; SessionID=3783a8fea972fb99779f7dd3078ed53c

Where to put the cookie(s) in this code?

string url;
string cookieHeader;
string formparam;
HttpWebRequest request;
HttpWebResponse response;
byte[] bytes;

url = "http://system.local/interface/Login.php";
formparam = string.Format("user_name=" + textBox1.Text + "&password=" + textBox2.Text + "&language=en&action%3Asubmit=Submit");
request = (HttpWebRequest)HttpWebRequest.Create(url);
var cookies = new CookieContainer();
request.ContentType = "Content-Type: application/x-www-form-urlencoded";
request.Method = "POST";
bytes = Encoding.ASCII.GetBytes(formparam);
request.ContentLength = bytes.Length;
request.KeepAlive = true;

using (Stream os = request.GetRequestStream())
{
    os.Write(bytes, 0, bytes.Length);
}

response = (HttpWebResponse)request.GetResponse();
cookieHeader = response.Headers["Set-Cookie"];


request = (HttpWebRequest)WebRequest.Create("http://system.local/interface/Login.php");
request.CookieContainer = new CookieContainer();
request.CookieContainer.Add(response.Cookies);
request.Headers.Add("Cookie", cookieHeader);

response = (HttpWebResponse)request.GetResponse();
using (StreamReader reader = new StreamReader(response.GetResponseStream()))
{
    //richTextBox1.Text = reader.ReadToEnd().Trim();
}

Answer 1

Set the CookieContainer field on every request, and it should automatically add the cookies from the header. Use the same CookieContainer instance every time and it will maintain its state across multiple requests. You don’t need to mess with Cookie or set-cookie header values, because the CookieContainer handles that automatically if it’s assigned to the request cookie container.

var cookies = new CookieContainer();

request.CookieContainer = cookies;
...
response = (HttpWebResponse)request.GetResponse();
// no need to manually read Cookie header, CookieContainer handles that.

request = ...
request.CookieContainer = cookies;
// no need to manually set/populate CookieContainer, just use the same instance.
...
response = (HttpWebResponse)request.GetResponse();
// etc