c# - MVC 自定义身份验证、授权和角色实现

Question

请耐心等待我提供问题的详细信息...

我有一个 MVC 站点，使用 FormsAuthentication 和自定义服务类进行身份验证、授权、角色/成员身份等。

身份验证

一共有三种登录方式:(1)邮箱+别名，(2)OpenID，(3)用户名+密码 em>。这三个都为用户提供了一个身份验证 cookie 并启动了一个 session 。前两个供访问者使用(仅限 session )，第三个供具有数据库帐户的作者/管理员使用。

public class BaseFormsAuthenticationService : IAuthenticationService
{
    // Disperse auth cookie and store user session info.
    public virtual void SignIn(UserBase user, bool persistentCookie)
    {
        var vmUser = new UserSessionInfoViewModel { Email = user.Email, Name = user.Name, Url = user.Url, Gravatar = user.Gravatar };

        if(user.GetType() == typeof(User)) {
            // roles go into view model as string not enum, see Roles enum below.
            var rolesInt = ((User)user).Roles;
            var rolesEnum = (Roles)rolesInt;
            var rolesString = rolesEnum.ToString();
            var rolesStringList = rolesString.Split(',').Select(role => role.Trim()).ToList();
            vmUser.Roles = rolesStringList;
        }

        // i was serializing the user data and stuffing it in the auth cookie
        // but I'm simply going to use the Session[] items collection now, so 
        // just ignore this variable and its inclusion in the cookie below.
        var userData = "";

        var ticket = new FormsAuthenticationTicket(1, user.Email, DateTime.UtcNow, DateTime.UtcNow.AddMinutes(30), false, userData, FormsAuthentication.FormsCookiePath);
        var encryptedTicket = FormsAuthentication.Encrypt(ticket);
        var authCookie = new HttpCookie(FormsAuthentication.FormsCookieName, encryptedTicket) { HttpOnly = true };
        HttpContext.Current.Response.Cookies.Add(authCookie);
        HttpContext.Current.Session["user"] = vmUser;
    }
}

角色

权限的简单标志枚举:

[Flags]
public enum Roles
{
    Guest = 0,
    Editor = 1,
    Author = 2,
    Administrator = 4
}

帮助枚举标志枚举的枚举扩展(哇!)。

public static class EnumExtensions
{
    private static void IsEnumWithFlags<T>()
    {
        if (!typeof(T).IsEnum)
            throw new ArgumentException(string.Format("Type '{0}' is not an enum", typeof (T).FullName));
        if (!Attribute.IsDefined(typeof(T), typeof(FlagsAttribute)))
            throw new ArgumentException(string.Format("Type '{0}' doesn't have the 'Flags' attribute", typeof(T).FullName));
    }

    public static IEnumerable<T> GetFlags<T>(this T value) where T : struct
    {
        IsEnumWithFlags<T>();
        return from flag in Enum.GetValues(typeof(T)).Cast<T>() let lValue = Convert.ToInt64(value) let lFlag = Convert.ToInt64(flag) where (lValue & lFlag) != 0 select flag;
    }
}

授权

服务提供了检查经过身份验证的用户角色的方法。

public class AuthorizationService : IAuthorizationService
{
    // Convert role strings into a Roles enum flags using the additive "|" (OR) operand.
    public Roles AggregateRoles(IEnumerable<string> roles)
    {
        return roles.Aggregate(Roles.Guest, (current, role) => current | (Roles)Enum.Parse(typeof(Roles), role));
    }

    // Checks if a user's roles contains Administrator role.
    public bool IsAdministrator(Roles userRoles)
    {
        return userRoles.HasFlag(Roles.Administrator);
    }

    // Checks if user has ANY of the allowed role flags.
    public bool IsUserInAnyRoles(Roles userRoles, Roles allowedRoles)
    {
        var flags = allowedRoles.GetFlags();
        return flags.Any(flag => userRoles.HasFlag(flag));
    }

    // Checks if user has ALL required role flags.
    public bool IsUserInAllRoles(Roles userRoles, Roles requiredRoles)
    {
        return ((userRoles & requiredRoles) == requiredRoles);
    }

    // Validate authorization
    public bool IsAuthorized(UserSessionInfoViewModel user, Roles roles)
    {
        // convert comma delimited roles to enum flags, and check privileges.
        var userRoles = AggregateRoles(user.Roles);
        return IsAdministrator(userRoles) || IsUserInAnyRoles(userRoles, roles);
    }
}

我选择通过属性在我的 Controller 中使用它:

public class AuthorizationFilter : IAuthorizationFilter
{
    private readonly IAuthorizationService _authorizationService;
    private readonly Roles _authorizedRoles;

    /// <summary>
    /// Constructor
    /// </summary>
    /// <remarks>The AuthorizedRolesAttribute is used on actions and designates the 
    /// required roles. Using dependency injection we inject the service, as well 
    /// as the attribute's constructor argument (Roles).</remarks>
    public AuthorizationFilter(IAuthorizationService authorizationService, Roles authorizedRoles)
    {
        _authorizationService = authorizationService;
        _authorizedRoles = authorizedRoles;
    }

    /// <summary>
    /// Uses injected authorization service to determine if the session user 
    /// has necessary role privileges.
    /// </summary>
    /// <remarks>As authorization code runs at the action level, after the 
    /// caching module, our authorization code is hooked into the caching 
    /// mechanics, to ensure unauthorized users are not served up a 
    /// prior-authorized page. 
    /// Note: Special thanks to TheCloudlessSky on StackOverflow.
    /// </remarks>
    public void OnAuthorization(AuthorizationContext filterContext)
    {
        // User must be authenticated and Session not be null
        if (!filterContext.HttpContext.User.Identity.IsAuthenticated || filterContext.HttpContext.Session == null)
            HandleUnauthorizedRequest(filterContext);
        else {
            // if authorized, handle cache validation
            if (_authorizationService.IsAuthorized((UserSessionInfoViewModel)filterContext.HttpContext.Session["user"], _authorizedRoles)) {
                var cache = filterContext.HttpContext.Response.Cache;
                cache.SetProxyMaxAge(new TimeSpan(0));
                cache.AddValidationCallback((HttpContext context, object o, ref HttpValidationStatus status) => AuthorizeCache(context), null);
            }
            else
                HandleUnauthorizedRequest(filterContext);             
        }
    }

我用这个属性装饰我的 Controller 中的操作，就像微软的 [Authorize] 一样，没有参数意味着让任何经过身份验证的人进入(对我来说它是 Enum = 0，不需要角色)。

关于背景信息的总结(呸)...写出所有这些我回答了我的第一个问题。在这一点上，我很好奇我的设置是否合适:

1. 我是否需要手动获取身份验证 cookie 并填充 HttpContext 的 FormsIdentity 主体，还是应该自动完成？

2. 在属性/过滤器 OnAuthorization() 中检查身份验证有任何问题吗？

3. 使用 Session[] 存储我的 View 模型与在 auth cookie 中序列化它有什么权衡？

4. 这个解决方案是否足够好地遵循“关注点分离”的理念？ (奖金，因为它是更面向意见的问题)

Answer 1

交叉发布自 my CodeReview answer :

我会尝试回答您的问题并提供一些建议:

1. 如果您在 web.config 中配置了 FormsAuthentication，它会自动为您提取 cookie，因此您不必手动填充 FormsIdentity。这在任何情况下都非常容易测试。

2. 您可能希望覆盖 AuthorizeCore 和 OnAuthorization 以获得有效的授权属性。 AuthorizeCore 方法返回一个 bool 值，用于确定用户是否有权访问给定资源。 OnAuthorization 不返回，一般用于根据身份验证状态触发其他事情。

3. 我认为 session 与 cookie 的问题在很大程度上是偏好问题，但出于一些原因我建议继续使用 session 。最大的原因是 cookie 随每个请求一起传输，虽然现在您可能只有一点点数据，但随着时间的推移谁知道您会在其中填充什么。添加加密开销，它可能会变得足够大以减慢请求速度。将它存储在 session 中还会将数据的所有权掌握在您手中(相对于将其放在客户手中并依靠您来解密和使用它)。我会提出的一个建议是将该 session 访问包装在静态 UserContext 类中，类似于 HttpContext，这样您就可以像 UserContext.Current 这样的调用。用户数据。请参阅下面的示例代码。

4. 我真的不能说这是否是一个很好的关注点分离，但对我来说它看起来是一个很好的解决方案。它与我见过的其他 MVC 身份验证方法没有什么不同。事实上，我在我的应用中使用了非常相似的东西。

最后一个问题 -- 为什么要手动构建和设置 FormsAuthentication cookie 而不是使用 FormsAuthentication.SetAuthCookie？只是好奇。

静态上下文类的示例代码

public class UserContext
{
    private UserContext()
    {
    }

    public static UserContext Current
    {
        get
        {
            if (HttpContext.Current == null || HttpContext.Current.Session == null)
                return null;

            if (HttpContext.Current.Session["UserContext"] == null)
                BuildUserContext();

            return (UserContext)HttpContext.Current.Session["UserContext"];
        }
    }

    private static void BuildUserContext()
    {
        BuildUserContext(HttpContext.Current.User);
    }

    private static void BuildUserContext(IPrincipal user)
    {
        if (!user.Identity.IsAuthenticated) return;

        // For my application, I use DI to get a service to retrieve my domain
        // user by the IPrincipal
        var personService = DependencyResolver.Current.GetService<IUserBaseService>();
        var person = personService.FindBy(user);

        if (person == null) return;

        var uc = new UserContext { IsAuthenticated = true };

        // Here is where you would populate the user data (in my case a SiteUser object)
        var siteUser = new SiteUser();
        // This is a call to ValueInjecter, but you could map the properties however
        // you wanted. You might even be able to put your object in there if it's a POCO
        siteUser.InjectFrom<FlatLoopValueInjection>(person);

        // Next, stick the user data into the context
        uc.SiteUser = siteUser;

        // Finally, save it into your session
        HttpContext.Current.Session["UserContext"] = uc;
    }


    #region Class members
    public bool IsAuthenticated { get; internal set; }
    public SiteUser SiteUser { get; internal set; }

    // I have this method to allow me to pull my domain object from the context.
    // I can't store the domain object itself because I'm using NHibernate and
    // its proxy setup breaks this sort of thing
    public UserBase GetDomainUser()
    {
        var svc = DependencyResolver.Current.GetService<IUserBaseService>();
        return svc.FindBy(ActiveSiteUser.Id);
    }

    // I have these for some user-switching operations I support
    public void Refresh()
    {
        BuildUserContext();
    }

    public void Flush()
    {
        HttpContext.Current.Session["UserContext"] = null;
    }
    #endregion
}

过去，我将属性直接放在 UserContext 类上以访问我需要的用户数据，但由于我已将其用于其他更复杂的项目，所以我决定将其移至SiteUser 类:

public class SiteUser
{
    public int Id { get; set; }
    public string FirstName { get; set; }
    public string LastName { get; set; }
    public string FullName
    {
        get { return FirstName + " " + LastName; }
    }
    public string AvatarUrl { get; set; }

    public int TimezoneUtcOffset { get; set; }

    // Any other data I need...
}