Not so tasty cookies

As a general rule I'll avoid web cookies, they've got a bad wrap, and are too often used and abused.

But for storing long life information on a client there's not really anything better.

So recently I was putting them into a site which would check when you first hit it if the cookie exists, if it didn't then create it. Having not used cookies for a while I'd lost touch with how they operate, especially in the ASP.NET collection.

Since HttpCookieCollection is a named collection you'd think that you could just got:

HttpCookie myCookie = Response.Cookies["myCookie"];

Well you can... sort of, I'll get to the sort of shortly, but some background.
Every time I did this I ended up with a cookie, regardless of whether one already existed or not. If it didn't exist then it'd have an expiry equal to DateTime.MinDate. Fine, what ever, I can detect that, so I had a handler to check that condition as well as a null return in myCookie.

Then I have the following lines:

HttpCookie myRealCookie = new HttpCookie("myCookie");
myRealCookie.Value = "something";
myRealCookie.Expiry = DateTime.Now.AddDays(1);

Response.Cookies.Add(myRealCookie);

But when I hit the control that is to use the cookie I get back the first "dud" cookie. WTF?
So I look at the HttpCookieCollection, low-and-behold I have 2 cookies named "myCookie". And when I try and get one out I always get the dud cookie.
WTF!

So I fire up Reflector and look squarly at what happens and this is what I found:

			public HttpCookie this[string name]{    
			

				get    {        
			

					return this.Get(name);    
			

				}
			

			}public HttpCookie Get(string name){    
			

				HttpCookie cookie = (HttpCookie) base.BaseGet(name);    
			

				if ((cookie == null) && (this._response != null))    {        
			

					cookie = new HttpCookie(name);        
			

					this.AddCookie(cookie, true);        
			

					this._response.OnCookieAdd(cookie);    
			

				}    
			

				return cookie;
			

			}