Sharing ASP.NET cookies across sub-domains

Question

I have two sites, both on the same domain, but with different sub-domains.
site1.mydomain.com site2.mydomain.com

Once I\'m authenticated on each, I look at the c

Answer 1

I've created a HttpContext extension method that will write a sub domain safe cookie.

Blog post and discussion

public static class HttpContextBaseExtenstions
{
    public static void SetSubdomainSafeCookie(this HttpContextBase context, string name, string value)
    {
        var domain = String.Empty;

        if (context.Request.IsLocal)
        {
            var domainSegments = context.Request.Url.Host.Split('.');
            domain = "." + String.Join(".", domainSegments.Skip(1));
        }
        else
        {
            domain = context.Request.Url.Host;
        }

        var cookie = new HttpCookie(name, value)
        {
            Domain = domain
        };

        context.Response.SetCookie(cookie);
    }
}

// usage
public class MyController : Controller
{
    public ActionResult Index()
    {
        this.Context.SetSubdomainSafeCookie("id", Guid.NewGuid().ToString());
        return View();
    }
}