Form认证的几点说明

有的页面需要用户认证之后才可以进入，通常都是在Filter的OnActionExecuting方法中我们需要获取当前用户。有两种情况不必登录：1.用户是登录的，也就是认证过的。2.用户上次登录了，但没有退出就关闭了页面，且还Cookie还没有过期。这个时候

Request.IsAuthenticated=true

所以用户不必再登录。

如果用户退出，也就是调用SignOut()

 public void SignOut()
        {
            _cachedUser = null;
            FormsAuthentication.SignOut();
        }

这个时候获取不到认证用户。

Filter就会让用户返回到登录页面。

 var user = WorkContext.CurrentUser;
if (user == null)
 {
    filterContext.Result = new RedirectResult("~/Account/Logon?returnUrl=" + returnUrl);
  }

另外，在Ninject中无法注入HttpContextBase,但可以讲其换成属性。

   public HttpContextBase HttpContext
        {
            get { return new HttpContextWrapper(System.Web.HttpContext.Current); }
        }

而对于Filter可以属性注入。

  [Inject]
  public IAuthenticationService AuthenticationService { get; set; }

LoginValidAttribute 源码：

 public class LoginValidAttribute : ActionFilterAttribute
    {
        /// <summary>
        /// 转到管理员登陆的界面
        /// </summary>
        private bool _isAdmin;

        public LoginValidAttribute(bool isadmin = false)
        {
            _isAdmin = isadmin;
        }

        public override void OnActionExecuting(ActionExecutingContext filterContext)
        {
            var contr = filterContext.RouteData.Values["controller"].ToString();
            var action = filterContext.RouteData.Values["action"].ToString();
            var parmdatas = filterContext.ActionParameters;
            var parms = "?";
            var i = 0;
            var count = parmdatas.Count;
            foreach (var parmdata in parmdatas)
            {
                i++;
                if (i <= count - 1)
                {
                    parms += parmdata.Key + "=" + parmdata.Value + "&";
                }
                else
                {
                    parms += parmdata.Key + "=" + parmdata.Value;

                }
            }
            if (count == 0) parms = "";
            var returnUrl = string.Format("~/{0}/{1}{2}", contr, action, parms);
            returnUrl = UrlHelper.GenerateContentUrl(returnUrl, filterContext.HttpContext);

            var user = WorkContext.CurrentUser;
            if (user == null)
            {
                filterContext.Result = new RedirectResult("~/Account/Logon?returnUrl=" + returnUrl);
            }

            // 如果已经登录 但不是角色，就需要跳转到只是页面 提示是管理员才能登录

        }

        [Inject]
        public IWorkContext WorkContext { get; set; }

    }

WebWorkContext：

  public class WebWorkContext : IWorkContext
    {
        #region Const

        #endregion

          #region Fields

        private readonly IUserService _userService;
        private User _cachedUser;

        #endregion

        public WebWorkContext( IUserService userService )
        {
            _userService = userService;
        }

        #region Utilities

        protected virtual HttpCookie GetUserCookie()
        {
            if (HttpContext == null || HttpContext.Request == null)
                return null;

            return HttpContext.Request.Cookies[PortalConfig.UserCookieName];
        }

        protected virtual void SetUserCookie(Guid customerGuid)
        {
            if (HttpContext != null && HttpContext.Response != null)
            {
                var cookie = new HttpCookie(PortalConfig.UserCookieName);
                cookie.HttpOnly = true;
                cookie.Value = customerGuid.ToString();
                if (customerGuid == Guid.Empty)
                {
                    cookie.Expires = DateTime.Now.AddMonths(-1);
                }
                else
                {
                    int cookieExpires = 24 * 30; //TODO make configurable
                    cookie.Expires = DateTime.Now.AddHours(cookieExpires);
                }

                HttpContext.Response.Cookies.Remove(PortalConfig.UserCookieName);
                HttpContext.Response.Cookies.Add(cookie);
            }
        }

        #endregion

        public virtual User CurrentUser
        {
            get
            {

                User customer = AuthenticationService.GetAuthenticatedCustomer(); ;

                //load guest customer
                if (customer == null || customer.Deleted || !customer.Active)
                {
                    var customerCookie = GetUserCookie();
                    if (customerCookie != null && !String.IsNullOrEmpty(customerCookie.Value))
                    {
                        Guid customerGuid;
                        if (Guid.TryParse(customerCookie.Value, out customerGuid))
                        {
                            var customerByCookie = _userService.GetUserByGuid(customerGuid);
                            if (customerByCookie != null &&IsCurrentUser)
                                //this customer (from cookie) should not be registered
                                //!customerByCookie.IsRegistered())
                                customer = customerByCookie;
                        }
                    }
                }

                //validation
                if (customer!=null&&!customer.Deleted && customer.Active)
                {
                    SetUserCookie(customer.UserGuid);
                }

                return customer;
                ;
            }
            set
            {
                SetUserCookie(value.UserGuid);
                _cachedUser = value;
            }
        }

        public User OriginalUserIfImpersonated { get; private set; }
        public bool IsAdmin { get; set; }
        public bool IsCurrentUser {
            get { return AuthenticationService.IsCurrentUser; }
        }

        public HttpContextBase HttpContext
        {
            get { return new HttpContextWrapper(System.Web.HttpContext.Current); }
        }

        [Inject]
        public IAuthenticationService AuthenticationService { get; set; }
    }

FormsAuthenticationService：

 public class FormsAuthenticationService : IAuthenticationService
    {
        private readonly IUserService _userService;
        private readonly TimeSpan _expirationTimeSpan;

        private User _cachedUser;

        public FormsAuthenticationService(IUserService userService)
        {
            _userService = userService;
            _expirationTimeSpan = FormsAuthentication.Timeout;
        }

        public void SignIn(User user, bool createPersistentCookie)
        {
            var now = DateTime.UtcNow.ToLocalTime();
            var ticket = new FormsAuthenticationTicket(1, user.Username, now, now.Add(_expirationTimeSpan),
                createPersistentCookie, user.Username, FormsAuthentication.FormsCookiePath);
            var encryptedTicket = FormsAuthentication.Encrypt(ticket);
            var cookie = new HttpCookie(FormsAuthentication.FormsCookieName, encryptedTicket) {HttpOnly = true};
            if (ticket.IsPersistent)
            {
                cookie.Expires = ticket.Expiration;
            }
            cookie.Secure = FormsAuthentication.RequireSSL;
            cookie.Path = FormsAuthentication.FormsCookiePath;
            if (FormsAuthentication.CookieDomain != null)
            {
                cookie.Domain = FormsAuthentication.CookieDomain;
            }
            HttpContext.Response.Cookies.Add(cookie);
            //nop源码中没有这一句，务必保证webconfig中的认证是form的。
           // FormsAuthentication.SetAuthCookie(user.Username, createPersistentCookie);
            _cachedUser = user;
        }

        public void SignOut()
        {
            _cachedUser = null;
            FormsAuthentication.SignOut();
        }

        public User GetAuthenticatedCustomer()
        {
            if (_cachedUser != null) return _cachedUser;
            if (HttpContext == null || HttpContext.Request == null || !HttpContext.Request.IsAuthenticated ||
                !(HttpContext.User.Identity is FormsIdentity))
            {
                return null;
            }
            var formsIdentity = (FormsIdentity)HttpContext.User.Identity;
            var user = GetAuthenticatedUserFromTicket(formsIdentity.Ticket);
            if (user != null && user.Active && !user.Deleted )//&& user.IsRegistered()
                _cachedUser = user;
            return _cachedUser;
        }

        public bool IsCurrentUser
        {
            get { return GetAuthenticatedCustomer() != null; }
        }

        public virtual User GetAuthenticatedUserFromTicket(FormsAuthenticationTicket ticket)
        {
            if (ticket == null)
                throw new ArgumentNullException("ticket");

            var usernameOrEmail = ticket.Name;

            if (String.IsNullOrWhiteSpace(usernameOrEmail))
                return null;

            var user = _userService.GetUserByUsername(usernameOrEmail);

            return user;
        }

        public HttpContextBase HttpContext
        {
            get { return new HttpContextWrapper(System.Web.HttpContext.Current); }
        }
    }