clear cookie container in WebRequest - cookies

Question

I'm using the WebRequest object to post data to a login page, then post data to a seperate page on the same site. I am instantiating a CookieContainer and assigning it to the WebRequest object so that the cookies are handled. The problem is that I do not want to retain the cookie after I post data to the other page. How can I delete that cookie?
private CookieContainer cookie_m;
protected CookieContainer CookieContainer
{
get
{
if (cookie_m == null)
{
cookie_m = new CookieContainer();
}
return cookie_m;
}
set
{
cookie_m = value;
}
}
protected virtual void SetData(WebRequest request, string sData)
{
if (!String.IsNullOrEmpty(sData))
{
byte[] binPostData = System.Text.Encoding.ASCII.GetBytes(sData);
request.ContentLength = binPostData.Length;
System.IO.Stream sRequest = request.GetRequestStream();
try
{
sRequest.Write(binPostData, 0, binPostData.Length);
}
finally
{
sRequest.Close();
}
}
}
private HttpWebRequest GetNewRequest(string sUrl)
{
HttpWebRequest request = (HttpWebRequest)WebRequest.Create(sUrl);
request.CookieContainer = this.CookieContainer;
request.Method = "POST";
request.ContentType = "application/x-www-form-urlencoded";
return request;
}
public override void Submit()
{
//Login
HttpWebRequest request = GetNewRequest("http://mytest/login.asp");
base.SetData(request, "action=validate_login&login=test&password=test");
WebResponse response = request.GetResponse();
System.IO.StreamReader sr = new System.IO.StreamReader(response.GetResponseStream());
string sResponse = sr.ReadToEnd();
//Entry screen
request = GetNewRequest("http://mytest/CustCreate.asp");
base.SetData(request, "Site=xyz&Cust=test");
response = request.GetResponse();
sr = new System.IO.StreamReader(response.GetResponseStream());
sResponse = sr.ReadToEnd();
//Sutmit
request = request = GetNewRequest("http://mytest/CustCreate.asp");
base.SetData(request, "Site=xyz&mydatahere&B1=Submit");
response = request.GetResponse();
sr = new System.IO.StreamReader(response.GetResponseStream());
sResponse = sr.ReadToEnd();
//How to delete cookies that have been saved?
}

Answer 1

To delete a cookie, you need to set the expiration date on it to a date in the past. This tells the browser it's expired and the browser will delete it.
Here's an example from msdn on how to do this in C# (not sure which language you're using).
if (Request.Cookies["UserSettings"] != null)
{
HttpCookie myCookie = new HttpCookie("UserSettings");
myCookie.Expires = DateTime.Now.AddDays(-1d);
Response.Cookies.Add(myCookie);
}