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430

answers:

2

For a web application I switched from using ASP.NET Membership to using my own log in system which just does something like this to mark a user as logged in:

Session["UserId"] = User.Id

Is it possible to store the user id in the ASPXAUTH cookie, piggybacking on its encryption, instead of using the standard session?

The goal is for the logged in state to last longer than a session and survive both browser and server restarts.

A: 

The ASPXAUTH cookie separates the authentication token from the session entirely, it's one of the reasons it's used. If your system uses session then it's really at odds with what forms authentication is trying to do.

If everything is in a session then really you don't need the authentication ticket at all, assuming the session is secured.

blowdart
I'm not using forms authentication anymore. I was just wondering if I could maintain the logged-in state in the ASPXAUTH cookie instead of the session.
J. Pablo Fernández
The logged in state is basically controlled by the presence of the cookie. If it's not there it's not logged in. Using a forms auth token instead of a normal cookie doesn't give you much more. Even then if everything is in session as you indicate then surely the session keeps a track of logged in or out?
blowdart
Whether a user is logged in is *not* controlled just by the presence of the cookie, otherwise anyone would just create a cookie and be logged in. The content of the cookie is important. .ASPXAUTH apparently stores the data in the cookie encrypted and lasts for as long as I want. Session stores an id in the cookie and the data in process, it generally lasts 20 minutes and dies if the process dies. I want the ASPXAUTH behavior for my login state data.
J. Pablo Fernández
I didn't say ASPXAUTH cookies did that, I'm say your session based system probably does. It would be cleared if you said why you have a session based login system and what exactly you want to store within a cookie that your session system cannot do for you.
blowdart
Well, yes, I'm currently storing it on the session and I want to store it on ASPXAUTH. That's it.
J. Pablo Fernández
Storing *what*? The forms auth ticket is keyed off a username, for which you could use your userID, but can contain anything you like in the UserData property.
blowdart
+2  A: 

Update: The original answer provided was with a project using MembershipProvider and it's explained in the answer itself. I, the asker, am not using it, so the answer to my problem was slightly different but extracted from this answer. I'm putting my answer at the bottom for anyone that cares and leaving the original verbatim, as it contains a lot of value.


Yes, you can use FormsAuthentication for your own strategy. And while the asp.net db structure does not suit you, you may provide a simple implementation of MembershipProvider to allow use of the Membership infrastructure. These two functionalities are not married so you may decide what fits for you.

Keeping in mind your question and some of the comments, here is a runnable example of how simple it is to leverage the provider model without being married to the default implementations and db schemas.

Using forms auth for your own purposes is simple. You just need to provide authentication and set your own ticket (cookie).

Using custom membership is almost as simple. You can implement as little or as much of the provider as you need to support the asp.net infrastructure features that you would like to employ.

e.g. in the sample below, I show that in the login process you may simply handle an event on the login control to validate credentials and the set the ticket. Done.

But I will also show how leveraging the provider model and implementing a custom membership provider can result in stronger, cleaner code. While we are in the custom membership provider I implement the minimum necessary to support using the Membership subsystem to provide easy access to a user's meta data without the need to write your own infrastructure.

Just drop these files into an empty project.

web.config


<?xml version="1.0"?>
<configuration>
  <system.web>
    <compilation debug="true"/>
    <authorization>
      <deny users="?"/>
    </authorization>
    <authentication mode="Forms"/>
    <!-- 
    optional but recommended. reusing the membership infrastructure via custom provider divorces 
    you from the aspnetdb but retains all of the baked in infrastructure which you do not have to 
    develop or maintain
    -->
    <membership defaultProvider="mine">
      <providers>
        <add name="mine" type="CustomAuthRepurposingFormsAuth.MyMembershipProvider"/>
      </providers>
    </membership>
  </system.web>
</configuration>

Site1.Master


<%@ Master Language="C#" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"&gt;
<html xmlns="http://www.w3.org/1999/xhtml"&gt;
<head runat="server">
    <title></title>
    <asp:ContentPlaceHolder ID="head" runat="server">
    </asp:ContentPlaceHolder>
</head>
<body>
    <form id="form1" runat="server">
    <div>
        <asp:LoginName ID="LoginName1" runat="server" />
        <asp:LoginStatus ID="LoginStatus1" runat="server" />
        <asp:ContentPlaceHolder ID="ContentPlaceHolder1" runat="server">
        </asp:ContentPlaceHolder>
    </div>
    </form>
</body>
</html>

Login.aspx


<%@ Page Title="" Language="C#" MasterPageFile="Site1.Master" %>
<%@ Import Namespace="CustomAuthRepurposingFormsAuth" %>
<script runat="server">

    /*
     * If you don't want to use a custom membership provider to authenticate
     * simply place your logic in the login control's handler and remove the 
     * membership element from config. It would have to take a very very 
     * compelling edge case to motivate me to not use a custom membership provider.
     * 
     */

    //protected void Login1_Authenticate(object sender, AuthenticateEventArgs e)
    //{
    //    // perform mindbendingly complex authentication logic
    //    e.Authenticated = Login1.UserName == Login1.Password;
    //}


    /*
     * set your cookie and you are golden
     */
    void Authenticated(object sender, EventArgs e)
    {
        // this is an arbitrary data slot you can use for ???
        // keep cookie size in mind when using it.
        string userData = "arbitraryData";
        Response.Cookies.Add(TicketHelper.CreateAuthCookie(Login1.UserName, userData, Login1.RememberMeSet /*persistent cookie*/));
    }

</script>

<asp:Content ID="Content1" ContentPlaceHolderID="head" runat="server">
</asp:Content>
<asp:Content ID="Content2" ContentPlaceHolderID="ContentPlaceHolder1" runat="server">
    <asp:Login ID="Login1" runat="server" OnLoggedIn="Authenticated" >
    </asp:Login>
    username==password==authenticated. <br />e.g.: uid: me, pwd:me
</asp:Content>

Default.aspx


<%@ Page Title="" Language="C#" MasterPageFile="Site1.Master" %>

<%@ Import Namespace="System.Security.Principal" %>
<%@ Import Namespace="CustomAuthRepurposingFormsAuth" %>

<script runat="server">
    protected void Page_Load(object sender, EventArgs e)
    {
        /*
         * you get this for free from asp.net
         */

        HttpContext page = HttpContext.Current;

        IIdentity identity = page.User.Identity;
        string username = identity.Name;
        bool authenticate = identity.IsAuthenticated;
        // or use the Request.IsAuthenticated convenience accessor

        /* 
         * you get this really cheap from forms auth
         * 
         * cost: validating credentials and setting your own ticket
         */

        // this page is protected by formsauth so the identity will actually 
        // be a FormsIdentity and you can get at the user data.
        // UserData is an appropriate place to store _small_ amounts of data
        var fIdent = (FormsIdentity)identity;
        string userData = fIdent.Ticket.UserData;


        // so, using only forms auth this is what you have to work with
        LblAuthenticated.Text = page.User.Identity.IsAuthenticated.ToString();
        LblUserId.Text = page.User.Identity.Name;
        LblUserData.Text = userData;

        /* 
         * this is an example of using a custom membership provider and subclassing the 
         * MembershipUser class to take advantage of the established mature infrastructure
         * 
         * this is entirely optional, you can delete the Membership section in web.config 
         * and delete MyMembershipProvider and MyMembershipUser and just use the authentication.
         * 
         */

        // get the custom field
        string myCustomField = ((MyMembershipUser)Membership.GetUser()).MyCustomField;
        LblMembership.Text = myCustomField;
    }        
</script>

<asp:Content ID="Content1" ContentPlaceHolderID="head" runat="server">
</asp:Content>
<asp:Content ID="Content2" ContentPlaceHolderID="ContentPlaceHolder1" runat="server">
    <br />
    Authenticated:<asp:Label ID="LblAuthenticated" runat="server" Text=""></asp:Label><br />
    UserId:<asp:Label ID="LblUserId" runat="server" Text=""></asp:Label><br />
    UserData:<asp:Label ID="LblUserData" runat="server" Text=""></asp:Label><br />
    <br />
    Membership User Custom Field:<asp:Label ID="LblMembership" runat="server" Text=""></asp:Label><br />
</asp:Content>

CustomAuthClasses.cs


using System;
using System.Web;
using System.Web.Security;

namespace CustomAuthRepurposingFormsAuth
{
    public static class TicketHelper
    {
        /// <summary>
        /// 
        /// </summary>
        /// <param name="userName"></param>
        /// <param name="userData">be mindful of the cookie size or you will be chasing ghosts</param>
        /// <param name="persistent"></param>
        /// <returns></returns>
        public static HttpCookie CreateAuthCookie(string userName, string userData, bool persistent)
        {
            DateTime issued = DateTime.Now;
            // formsAuth does not expose timeout!? have to hack around the
            // spoiled parts and keep moving..
            HttpCookie fooCookie = FormsAuthentication.GetAuthCookie("foo", true);
            int formsTimeout = Convert.ToInt32((fooCookie.Expires - DateTime.Now).TotalMinutes);

            DateTime expiration = DateTime.Now.AddMinutes(formsTimeout);
            string cookiePath = FormsAuthentication.FormsCookiePath;

            var ticket = new FormsAuthenticationTicket(0, userName, issued, expiration, true, userData, cookiePath);
            return CreateAuthCookie(ticket, expiration, persistent);
        }

        public static HttpCookie CreateAuthCookie(FormsAuthenticationTicket ticket, DateTime expiration, bool persistent)
        {
            string creamyFilling = FormsAuthentication.Encrypt(ticket);
            var cookie = new HttpCookie(FormsAuthentication.FormsCookieName, creamyFilling)
                             {
                                 Domain = FormsAuthentication.CookieDomain,
                                 Path = FormsAuthentication.FormsCookiePath
                             };
            if (persistent)
            {
                cookie.Expires = expiration;
            }

            return cookie;
        }
    }

    /// <summary>
    /// This is an example of inheriting MembershipUser to
    /// expose arbitrary data that may be associated with your
    /// user implementation.
    /// 
    /// You may repurpose existing fields on the base and add your own.
    /// Just perform a cast on the MembershipUser returned from your
    /// MembershipProvider implementation
    /// </summary>
    public class MyMembershipUser : MembershipUser
    {
        public MyMembershipUser(string providerName, string name, object providerUserKey, string email,
                                string passwordQuestion, string comment, bool isApproved, bool isLockedOut,
                                DateTime creationDate, DateTime lastLoginDate, DateTime lastActivityDate,
                                DateTime lastPasswordChangedDate, DateTime lastLockoutDate)
            : base(
                providerName, name, providerUserKey, email, passwordQuestion, comment, isApproved, isLockedOut,
                creationDate, lastLoginDate, lastActivityDate, lastPasswordChangedDate, lastLockoutDate)
        {
        }

        protected MyMembershipUser()
        {
        }

        // e.g. no desire to use Profile, can just add data
        // say, from a flat record containing all user data
        public string MyCustomField { get; set; }
    }

    /// <summary>
    /// At the most basic level, implementing a MembershipProvider allows you to
    /// reuse established framework code. In this case, we just provide services
    /// for the Login control and user identification via Membership subsystem.
    /// </summary>
    public class MyMembershipProvider : MembershipProvider
    {
        #region Minimum implementation in order to use established authentication and identification infrastructure

        /// <summary>
        /// You can just do this in the login logic if you do not want
        /// leverage framework for membership user access
        /// </summary>
        public override bool ValidateUser(string username, string password)
        {
            return username == password;
        }


        public override MembershipUser GetUser(string username, bool userIsOnline)
        {
            /*
             * Simulate going to the DB to get the data
             */

            // membership user non nullable fields, repurpose or use
            // implied null value e.g DateTime.MinValue;

            var createdDate = new DateTime(2009, 10, 25);
            var lastLogin = new DateTime(2009, 10, 25);
            var lastActivity = new DateTime(2009, 10, 25);
            var lastPasswordChange = new DateTime(2009, 10, 25);
            var lastLockoutDate = new DateTime(2009, 10, 25);

            object providerUserKey = 3948; // e.g. user primary key. 


            /*
             * build your custom user and send it back to asp.net
             */

            // need to use the full constructor to set the username and key
            var user = new MyMembershipUser(Name, username, providerUserKey, null, null, null, true, false, createdDate,
                                            lastLogin,
                                            lastActivity, lastPasswordChange, lastLockoutDate)
                           {
                               MyCustomField = "Hey"
                           };

            return user;
        }

        #endregion

        #region Optional implementations depending on the framework features you would like to leverage.

        public override bool EnablePasswordRetrieval
        {
            get { throw new NotImplementedException(); }
        }

        public override bool EnablePasswordReset
        {
            get { throw new NotImplementedException(); }
        }

        public override bool RequiresQuestionAndAnswer
        {
            get { throw new NotImplementedException(); }
        }

        public override string ApplicationName
        {
            get { throw new NotImplementedException(); }
            set { throw new NotImplementedException(); }
        }

        public override int MaxInvalidPasswordAttempts
        {
            get { throw new NotImplementedException(); }
        }

        public override int PasswordAttemptWindow
        {
            get { throw new NotImplementedException(); }
        }

        public override bool RequiresUniqueEmail
        {
            get { throw new NotImplementedException(); }
        }

        public override MembershipPasswordFormat PasswordFormat
        {
            get { throw new NotImplementedException(); }
        }

        public override int MinRequiredPasswordLength
        {
            get { throw new NotImplementedException(); }
        }

        public override int MinRequiredNonAlphanumericCharacters
        {
            get { throw new NotImplementedException(); }
        }

        public override string PasswordStrengthRegularExpression
        {
            get { throw new NotImplementedException(); }
        }

        public override MembershipUser GetUser(object providerUserKey, bool userIsOnline)
        {
            throw new NotImplementedException();
        }


        public override MembershipUser CreateUser(string username, string password, string email,
                                                  string passwordQuestion, string passwordAnswer, bool isApproved,
                                                  object providerUserKey, out MembershipCreateStatus status)
        {
            throw new NotImplementedException();
        }

        public override bool ChangePasswordQuestionAndAnswer(string username, string password,
                                                             string newPasswordQuestion, string newPasswordAnswer)
        {
            throw new NotImplementedException();
        }

        public override string GetPassword(string username, string answer)
        {
            throw new NotImplementedException();
        }

        public override bool ChangePassword(string username, string oldPassword, string newPassword)
        {
            throw new NotImplementedException();
        }

        public override string ResetPassword(string username, string answer)
        {
            throw new NotImplementedException();
        }

        public override void UpdateUser(MembershipUser user)
        {
            throw new NotImplementedException();
        }

        public override bool UnlockUser(string userName)
        {
            throw new NotImplementedException();
        }


        public override string GetUserNameByEmail(string email)
        {
            throw new NotImplementedException();
        }

        public override bool DeleteUser(string username, bool deleteAllRelatedData)
        {
            throw new NotImplementedException();
        }

        public override MembershipUserCollection GetAllUsers(int pageIndex, int pageSize, out int totalRecords)
        {
            throw new NotImplementedException();
        }

        public override int GetNumberOfUsersOnline()
        {
            throw new NotImplementedException();
        }

        public override MembershipUserCollection FindUsersByName(string usernameToMatch, int pageIndex, int pageSize,
                                                                 out int totalRecords)
        {
            throw new NotImplementedException();
        }

        public override MembershipUserCollection FindUsersByEmail(string emailToMatch, int pageIndex, int pageSize,
                                                                  out int totalRecords)
        {
            throw new NotImplementedException();
        }

        #endregion
    }
}

Solution actually used (in as ASP.NET MVC project using OpenID):

I have an AccountController which I use to log users in and out and these methods are there.

#region Methods to log in a user.
/// <summary>
/// Create the auth cookie in the same way it is created my ASP.NET Membership system, hopefully lasting for more than 20 minutes.
/// 
/// For more information check out http://stackoverflow.com/questions/2122831/is-it-possible-to-use-aspxauth-for-my-own-logging-system
/// </summary>
/// <param name="userId">Id of the user that is logged in</param>
/// <returns>Cookie created to mark the user as authenticated.</returns>
private static HttpCookie CreateAuthCookie(int userId) {
  DateTime issued = DateTime.Now;
  // formsAuth does not expose timeout!? have to hack around the spoiled parts and keep moving..
  HttpCookie fooCookie = FormsAuthentication.GetAuthCookie("foo", true);
  int formsTimeout = Convert.ToInt32((fooCookie.Expires - DateTime.Now).TotalMinutes);

  DateTime expiration = DateTime.Now.AddMinutes(formsTimeout);

  var ticket = new FormsAuthenticationTicket(0, userId.ToString(), issued, expiration, true, "", FormsAuthentication.FormsCookiePath);
  return CreateAuthCookie(ticket, expiration, true);
}

/// <summary>
/// Create an auth cookie with the ticket data.
/// </summary>
/// <param name="ticket">Ticket containing the data to mark a user as authenticated.</param>
/// <param name="expiration">Expriation date for the cookie.</param>
/// <param name="persistent">Whether it's persistent or not.</param>
/// <returns>Cookie created to mark the user as authenticated.</returns>
private static HttpCookie CreateAuthCookie(FormsAuthenticationTicket ticket, DateTime expiration, bool persistent) {
  string encryptedAuthData = FormsAuthentication.Encrypt(ticket);
  var cookie = new HttpCookie(FormsAuthentication.FormsCookieName, encryptedAuthData) {
    Domain = FormsAuthentication.CookieDomain,
    Path = FormsAuthentication.FormsCookiePath
  };
  if (persistent) {
    cookie.Expires = expiration;
  }

  return cookie;
}

/// <summary>
/// Expire the authentication cookie effectively loging out a user.
/// </summary>
private void ExpireAuthCookie() {
  var cookie = new HttpCookie(FormsAuthentication.FormsCookieName);
  cookie.Expires = DateTime.Now.AddDays(-1);
  Response.Cookies.Add(cookie);
}
#endregion
Sky Sanders
How would I do that without using the usual membership setup?
J. Pablo Fernández
@J. Pablo Fernández, Sure, actually you _can_ use the forms authentication subsystem as-is with your own membership implementation. And if you wanted to subvert the membership subsystem is simple. am working on a sample right now.
Sky Sanders
Thanks Sky Sanders, a lot!
J. Pablo Fernández