How can I manually create a authentication cookie instead of the default method?

Question

Using FormsAuthentication we write code like this:

 if (IsValidUser())  {       FormsAuthentication.SetAuthCookie(userName, createPersistentCookie);       FormsAuthentication.RedirectFromLoginPage(userName, createPersistentCookie);   } 

1. How can I manually create a authentication cookie instead of writing FormsAuthentication.SetAuthCookie(userName, createPersistentCookie)?

2. How can I store a redirect URL from the login page in a string variable instead of writing FormsAuthentication.RedirectFromLoginPage(userName, createPersistentCookie)?

Answer 1

Here you go. ASP.NET takes care of this for you when you use the higher level methods built into FormsAuthentication, but at the low level this is required to create an authentication cookie.

if (Membership.ValidateUser(username, password)) {     // sometimes used to persist user roles   string userData = string.Join("|",GetCustomUserRoles());    FormsAuthenticationTicket ticket = new FormsAuthenticationTicket(     1,                                     // ticket version     username,                              // authenticated username     DateTime.Now,                          // issueDate     DateTime.Now.AddMinutes(30),           // expiryDate     isPersistent,                          // true to persist across browser sessions     userData,                              // can be used to store additional user data     FormsAuthentication.FormsCookiePath);  // the path for the cookie    // Encrypt the ticket using the machine key   string encryptedTicket = FormsAuthentication.Encrypt(ticket);    // Add the cookie to the request to save it   HttpCookie cookie = new HttpCookie(FormsAuthentication.FormsCookieName, encryptedTicket);   cookie.HttpOnly = true;    Response.Cookies.Add(cookie);    // Your redirect logic   Response.Redirect(FormsAuthentication.GetRedirectUrl(username, isPersistent)); } 

I'm not sure why you would want to do something custom here. If you want to change the implementation of where user data is stored and how users authenticate then it's best practice to create a custom MembershipProvider. Rolling your own solution and messing with the authentication cookie means a high probability of introducing security holes in your software.

I don't understand your part 2. You only need to call FormsAuthentication.GetRedirectUrl if you want to return users to the page they were trying to access when they got bounced to login. If not do whatever you want here, redirect to a url stored in the configuration if you want.

To read the FormsAuthentication cookie, normally you would hook the AuthenticateRequest event in a HttpModule or the Global.asax and set up the user IPrinciple context.

protected void Application_AuthenticateRequest(Object sender, EventArgs e) {     HttpCookie authCookie = Request.Cookies[FormsAuthentication.FormsCookieName];     if(authCookie != null)     {         //Extract the forms authentication cookie         FormsAuthenticationTicket authTicket = FormsAuthentication.Decrypt(authCookie.Value);          // If caching roles in userData field then extract         string[] roles = authTicket.UserData.Split(new char[]{'|'});          // Create the IIdentity instance         IIdentity id = new FormsIdentity( authTicket );          // Create the IPrinciple instance         IPrincipal principal = new GenericPrincipal(id, roles);          // Set the context user          Context.User = principal;     } }