How to create persistent cookies in asp.net?

Question

Hi,

I am creating cookies with following lines:

HttpCookie userid = new HttpCookie("userid", objUser.id.ToString());
userid.Expires.AddYears(1);
Response.Cookies.Add(userid);

Now How to make it persistent?

Because if I visit the same page again after closing the browser, I'm unable to get it back.

Answer 1

You need to add this as the last line...

HttpContext.Current.Response.Cookies.Add(userid);

When you need to read the value of the cookie, you'd use a method similar to this:

    string cookieUserID= String.Empty;

    try
    {
        if (HttpContext.Current.Request.Cookies["userid"] != null)
        {
            cookieUserID = HttpContext.Current.Request.Cookies["userid"];
        }
    }
    catch (Exception ex)
    {
       //handle error
    }

    return cookieUserID;

Answer 2

Here's how you can do that.

Writing the persistent cookie.

//create a cookie
HttpCookie myCookie = new HttpCookie("myCookie");

//Add key-values in the cookie
myCookie.Values.Add("userid", objUser.id.ToString());

//set cookie expiry date-time. Made it to last for next 12 hours.
myCookie.Expires = DateTime.Now.AddHours(12);

//Most important, write the cookie to client.
Response.Cookies.Add(myCookie);

Reading the persistent cookie.

//Assuming user comes back after several hours. several < 12.
//Read the cookie from Request.
HttpCookie myCookie = Request.Cookies["myCookie"];
if (myCookie == null)
{
    //No cookie found or cookie expired.
    //Handle the situation here, Redirect the user or simply return;
}

//ok - cookie is found.
//Gracefully check if the cookie has the key-value as expected.
if (!string.IsNullOrEmpty(myCookie.Values["userid"]))
{
    string userId = myCookie.Values["userid"].ToString();
    //Yes userId is found. Mission accomplished.
}

Answer 3

FWIW be very careful with storing something like a userid in a cookie unencrypted. Doing this makes your site very prone to cookie poisoning where users can easily impersonate another user. If you are considering something like this I would highly recommend using the forms authentication cookie directly.

bool persist = true;

var cookie = FormsAuthentication.GetAuthCookie(loginUser.ContactId, persist);

cookie.Expires = DateTime.Now.AddMonths(3);

var ticket = FormsAuthentication.Decrypt(cookie.Value);

var userData = "store any string values you want inside the ticket
                 extra than user id that will be encrypted"

var newTicket = new FormsAuthenticationTicket(ticket.Version, ticket.Name,
     ticket.IssueDate, ticket.Expiration, ticket.IsPersistent, userData);

cookie.Value = FormsAuthentication.Encrypt(newTicket);

Response.Cookies.Add(cookie);

Then you can read this at any time from an ASP.NET page by doing

string userId = null;
if(this.Context.User.Identity.IsAuthenticated)
    userid = this.Context.User.Identity.Name;