How do you remove HttpOnly cookies? - c#

If my application places HttpOnly cookies on a client and then needs to remove them how can you remove them completely?

You can cause the cookie to expire when the user visits your website, for example:
HttpCookie expiredCookie = new HttpCookie(cookieName);
expiredCookie.Expires = DateTime.UtcNow.AddDays(-1);
Response.Cookies.Add(expiredCookie);
You'll have to do this for every cookie you want to be removed.

You can't reach out and delete cookies. You can take all the cookies, wipe out the data and make them expired though.

Related

How do I set cookie expiration to session in C#

I am creating a website, and I'm not sure how to use sessions with cookies.
When sessions timeout, I want to show the username and time of the user; for e.g., username stored in cookies and session. When sessions timeout the username must be retrived from the cookies.
Lets put things in perspective first.
A session is the session a user is experiencing when he is using the website.
How it works is basically a user starts a session with the web server, the web server then gives it a key of the session and sets a timeout for the session which are stored as a cookie.
Since this process is automatic and you can only configure it in web.config (unless you are asp.net core vNext, which I doubt) with sessionState https://msdn.microsoft.com/en-us/library/h6bb9cz9%28v=vs.80%29.aspx
A normal HttpCookie on another hand is something you set on your Response object and can give it a specific expiration date like this:
HttpCookie myCookie = new HttpCookie("MyTestCookie");
DateTime now = DateTime.Now;
// Set the cookie value.
myCookie.Value = now.ToString();
// Set the cookie expiration date.
myCookie.Expires = now.AddMinutes(1);
// Add the cookie.
Response.Cookies.Add(myCookie);
Which suits your needs more likely.
If you want more information about sessions expiration I'd also suggest you check out http://www.hanselman.com/blog/TroubleshootingExpiredASPNETSessionStateAndYourOptions.aspx

How do I manually delete a cookie in asp.net MVC 4

I need to delete authentication cookie manually (Instead of using FormsAuthentication.SignOut whcih for some reasons does not work). I tried
System.Web.HttpContext.Request.Cookies.Remove(cookieName); // for example .ASPXAUTH
System.Web.HttpContext.Response.Cookies.Remove(cookieName); // for example .ASPXAUTH
FormsAuthentication.SignOut(); // I don't know why this one does not work
Neither of those command work. In fact Response cookies are empty and request cookie contains the cookie I want to delete when the following commands are executed it no longer contains the cookie I deleted but in browser the cookie still exists and I am able to do things that authorized users can even after signing out.
Try:
if (Request.Cookies["MyCookie"] != null)
{
var c = new HttpCookie("MyCookie")
{
Expires = DateTime.Now.AddDays(-1)
};
Response.Cookies.Add(c);
}
More information on MSDN.
c.Expires = DateTime.Now.AddDays(-1);
This does not clear cookies instantly.
Use this: c.Expires = DateTime.Now.AddSeconds(1);
This will clear cookies instantly.

Cookies don't persist after refresh

I am using c# and mvc. I am trying to write a cookie to the user browser. But after a refresh of the browser the cookie disappears.
This is my code for writing the cookie:
movieCookie = new HttpCookie(cookieName);
movieCookie.Value = "test;
movieCookie.Expires = DateTime.Now.AddDays(30);
//add the cookie
HttpContext.Current.Response.Cookies.Add(movieCookie);
and the one for reading the cookie:
//check if such cookie exist
HttpCookie movieCookie = null;
if (HttpContext.Current.Request.Cookies.AllKeys.Contains(cookieName))
movieCookie = HttpContext.Current.Request.Cookies[cookieName];
Another thing to add is that when I searched "AllKeys" like so:
HttpContext.Current.Request.Cookies.AllKeys
it shows an empty string array, for some reason.
any ideas?
Some possibly silly questions
Check your web-servers time and date, are they set correctly, if they are (in your case) 2 years out it will expire cookies immediately.
Check that cookieName is the same
Check that after setting the cookie to the response your not redirecting before the cookie is set. For a cookie to be set you need to set headers and push them out.
I solved it. It appears that in MVC the "return view" after the cookie creation, cause the cookie not to be saved.

How to remove all expired cookie from CookieCollection?

How to remove all expired cookie from a CookieCollection ?
Try this.
var cookies = Request.Cookies;
foreach (HttpCookie cookie in cookies)
{
if (cookie.Expires < DateTime.Now)
{
Request.Cookies.Remove(cookie.Name);
}
}
Please note the excerpt from MSDN,
Calling the Remove method of the Cookies collection removes the cookie
from the collection on the server side, so the cookie will not be sent
to the client. However, the method does not remove the cookie from the
client if it already exists there.
You cannot directly delete a cookie on a user's computer. However, you can direct the user's browser to delete the cookie by setting the cookie's expiration date to a past date. The next time a user makes a request to a page within the domain or path that set the cookie, the browser will determine that the cookie has expired and remove it.
if (Request.Cookies["UserSettings"] != null)
{
HttpCookie myCookie = new HttpCookie("UserSettings");
myCookie.Expires = DateTime.Now.AddDays(-1);//add -1 days
Response.Cookies.Add(myCookie);
}
The way you remove a cookie is to change it expire date to some thing that has already passed.. but a expired cookie should never be sent from the browser in the first case...

Cookie is not getting deleted in IE 8

I'm trying to delete a cookie but somehow it is not getting deleted in IE 8
This is the code i'm using
HttpCookie userCookie = Request.Cookies[cookieName];
if (userCookie != null)
{
userCookie.Expires = DateTime.Now.AddDays(-1);
if (!string.IsNullOrEmpty(cookieDomain))
userCookie.Domain = cookieDomain;
Response.Cookies.Add(userCookie);
}
It is working fine in firfox and chrome .
Suppose the name of the cookie is testcookie. We created this cookie from xyz.com and we set the domain of the cookie as ".xyz.com". Now we are deleting or expiring this cookie from subdomain.xyz.com. We are deleting the cookie with the code we have mentioned above.
Check your cookies. You may have two cookies called "testcookie" or whatever. This has happened to me before and caused a lot of pain. You can check quickly by typing javascript:alert(document.cookie) into the address bar.
If you have got duplicate cookies delete all your cookies and start testing again. I.e. setting your testcookie, then on another request try expiring it again how you were before.

Categories