AuthorizeAttribute是asp.net MVC的几大过滤器之一，俗称认证和授权过滤器，也就是判断登录与否，授权与否。当为某一个Controller或Action附加该特性时，没有登录或授权的账户是不能访问这些Controller或Action的。
在进入一个附加了Authorize特性的Controller或Action之前，首先执行的是AuthorizeAttribute类的OnAuthorization(AuthorizationContext filterContext)方法，接着OnAuthorization方法会去调用其他的诸如AuthorizeCore方法。
在将AuthorizeAttribute类反编译之后得到如下代码，一看就清晰明了：
using System; using System.Collections.Generic; using System.Linq; using System.Security.Principal; using System.Web.Mvc.Properties; namespace System.Web.Mvc { /// <summary>Specifies that access to a controller or action method is restricted to users who meet the authorization requirement.</summary> [AttributeUsage(AttributeTargets.Class | AttributeTargets.Method, Inherited = true, AllowMultiple = true)] public class AuthorizeAttribute : FilterAttribute, IAuthorizationFilter { private static readonly char[] _splitParameter = new char[] { ',' }; private readonly object _typeId = new object(); private string _roles; private string[] _rolesSplit = new string[0]; private string _users; private string[] _usersSplit = new string[0]; /// <summary>Gets or sets the user roles that are authorized to access the controller or action method.</summary> /// <returns>The user roles that are authorized to access the controller or action method.</returns> public string Roles { get { return this._roles ?? string.Empty; } set { this._roles = value; this._rolesSplit = AuthorizeAttribute.SplitString(value); } } /// <summary>Gets the unique identifier for this attribute.</summary> /// <returns>The unique identifier for this attribute.</returns> public override object TypeId { get { return this._typeId; } } /// <summary>Gets or sets the users that are authorized to access the controller or action method.</summary> /// <returns>The users that are authorized to access the controller or action method.</returns> public string Users { get { return this._users ?? string.Empty; } set { this._users = value; this._usersSplit = AuthorizeAttribute.SplitString(value); } } /// <summary>When overridden, provides an entry point for custom authorization checks.</summary> /// <returns>true if the user is authorized; otherwise, false.</returns> /// <param name="httpContext">The HTTP context, which encapsulates all HTTP-specific information about an individual HTTP request.</param> /// <exception cref="T:System.ArgumentNullException">The <paramref name="httpContext" /> parameter is null.</exception> protected virtual bool AuthorizeCore(HttpContextBase httpContext) { if (httpContext == null) { throw new ArgumentNullException("httpContext"); } IPrincipal user = httpContext.User; return user.Identity.IsAuthenticated && (this._usersSplit.Length <= 0 || this._usersSplit.Contains(user.Identity.Name, StringComparer.OrdinalIgnoreCase)) && (this._rolesSplit.Length <= 0 || this._rolesSplit.Any(new Func<string, bool>(user.IsInRole))); } private void CacheValidateHandler(HttpContext context, object data, ref HttpValidationStatus validationStatus) { validationStatus = this.OnCacheAuthorization(new HttpContextWrapper(context)); } /// <summary>Called when a process requests authorization.</summary> /// <param name="filterContext">The filter context, which encapsulates information for using <see cref="T:System.Web.Mvc.AuthorizeAttribute" />.</param> /// <exception cref="T:System.ArgumentNullException">The <paramref name="filterContext" /> parameter is null.</exception> public virtual void OnAuthorization(AuthorizationContext filterContext) { if (filterContext == null) { throw new ArgumentNullException("filterContext"); } if (OutputCacheAttribute.IsChildActionCacheActive(filterContext)) { throw new InvalidOperationException(MvcResources.AuthorizeAttribute_CannotUseWithinChildActionCache); } bool flag = filterContext.ActionDescriptor.IsDefined(typeof(AllowAnonymousAttribute), true) || filterContext.ActionDescriptor.ControllerDescriptor.IsDefined(typeof(AllowAnonymousAttribute), true); if (flag) { return; } if (this.AuthorizeCore(filterContext.HttpContext)) { HttpCachePolicyBase cache = filterContext.HttpContext.Response.Cache; cache.SetProxyMaxAge(new TimeSpan(0L)); cache.AddValidationCallback(new HttpCacheValidateHandler(this.CacheValidateHandler), null); return; } this.HandleUnauthorizedRequest(filterContext); } /// <summary>Processes HTTP requests that fail authorization.</summary> /// <param name="filterContext">Encapsulates the information for using <see cref="T:System.Web.Mvc.AuthorizeAttribute" />. The <paramref name="filterContext" /> object contains the controller, HTTP context, request context, action result, and route data.</param> protected virtual void HandleUnauthorizedRequest(AuthorizationContext filterContext) { filterContext.Result = new HttpUnauthorizedResult(); } /// <summary>Called when the caching module requests authorization.</summary> /// <returns>A reference to the validation status.</returns> /// <param name="httpContext">The HTTP context, which encapsulates all HTTP-specific information about an individual HTTP request.</param> /// <exception cref="T:System.ArgumentNullException">The <paramref name="httpContext" /> parameter is null.</exception> protected virtual HttpValidationStatus OnCacheAuthorization(HttpContextBase httpContext) { if (httpContext == null) { throw new ArgumentNullException("httpContext"); } if (!this.AuthorizeCore(httpContext)) { return HttpValidationStatus.IgnoreThisRequest; } return HttpValidationStatus.Valid; } internal static string[] SplitString(string original) { if (string.IsNullOrEmpty(original)) { return new string[0]; } IEnumerable<string> source = from piece in original.Split(AuthorizeAttribute._splitParameter) let trimmed = piece.Trim() where !string.IsNullOrEmpty(trimmed) select trimmed; return source.ToArray<string>(); } } }
通过以上描述，我们可以在自己的MVC程序中使用AuthorizeAttribute类或者其派生的子类来达到用户认证和授权的目的。
一、新建一个MVC项目
新建一个MVC项目，选择不用身份验证。
二、添加Model
为了达到演示目的，添加了一个简单的StudentViewModel，用来显示业务数据：
public class StudentViewModel { public int ID { get; set; } public string Name { get; set; } public string Tel { get; set; } }
添加一个UserViewModel，用来进行登录和角色授权：
public class UserViewModel { [DisplayName("用户名")] public string UserName { get; set; } [DisplayName("密 码")] public string Pwd { get; set; } public Role Role { get; set; } } public enum Role { Admin=1, Normal=2, System=3 }
OK，本篇讲述就不去访问数据库了，直接用业务数据。然后我们再新建一个Data类，存放业务数据：
public class Data { public static List<StudentViewModel> students = new List<StudentViewModel> { new StudentViewModel { ID=1, Name="张三", Tel="15808038502" }, new StudentViewModel { ID=2, Name="李四", Tel="15708032302" }, new StudentViewModel { ID=3, Name="王五", Tel="15562438502" }, new StudentViewModel { ID=4, Name="赵六", Tel="15064534502" }, new StudentViewModel { ID=5, Name="孙琦", Tel="15185465402" } }; public static List<UserViewModel> users = new List<UserViewModel> { new UserViewModel { UserName="admin", Pwd="1", Role=Role.Admin }, new UserViewModel { UserName="normal", Pwd="1", Role=Role.Normal}, new UserViewModel { UserName="system", Pwd="1", Role=Role.System} }; }
三、创建Controller控制器和视图
1、新建StudentController
Index视图是显示全部的Student数据，FindOne是显示一条Student数据。：
public class StudentController : Controller { public ActionResult Index() { return View(Data.Data.students); } public ActionResult FindOne(int? id) { return View("Index", Data.Data.students.Where(s => s.ID == id)); } }
现在没有对Student控制器做任何的身份和授权访问限制。接下来我们创建一个登陆用的控制器。
2、新建AccountController
public class AccountController : Controller { //用于获取登录页面 [HttpGet] public ActionResult Login() { return View(); } //用于登录验证 [HttpPost] public ActionResult Login(LoginViewModel login) { if (ModelState.IsValid) { UserViewModel clogin = Data.Data.users.Where(u => u.UserName == login.UserName && u.Pwd == login.Pwd).FirstOrDefault(); if (clogin != null) { //FormsAuthentication.SetAuthCookie有两个参数 //第一个参数：设置当前登录用户的标识，可以自定义 //第二个参数： //true:设置永久的。可以在web.config中设置过期时间，喏，下面的timeout就是过期时间，以分钟为单位。如下所示： // < system.web > // < authentication mode = "Forms" > // < forms loginUrl = "~/Account/Login" timeout = "2" /> // </ authentication > // </ system.web > //false：设置当前会话时间为有效时间，浏览器或页面已关闭就需要重新登录。 FormsAuthentication.SetAuthCookie(clogin.UserName, false); return RedirectToAction("FindOne", "Student", new { id = 1 }); } } return View(); } //用于注销登录 [Authorize] [NoCache] public ActionResult LoginOut() { FormsAuthentication.SignOut(); return RedirectToAction("Login", "Account"); } //用于显示无权限消息 public ActionResult NoPemission() { return View(); } }
登陆页面如下：
@model MVCDemo2.ViewModels.UserViewModel @{ Layout = null; } <!DOCTYPE html> <html> <head> <meta name="viewport" content="width=device-width" /> <title>Login</title> <link href="~/Content/w3.css" rel="stylesheet" /> <style> html, body { margin: 0; padding: 0; } .main { 400px; height: 300px; position: absolute; left: 0; top: 0; right: 0; bottom: 0; margin: auto; } </style> </head> <body> <div class="main"> <h3 class="w3-teal w3-center w3-margin-0" style="100%;">权限管理系统</h3> @using (Html.BeginForm("Login", "Account", FormMethod.Post, new { @class = "w3-container w3-card-4 w3-light-grey", style = "100%;" })) { <table class="w3-table"> <tr> <td style="20%; vertical-align:middle;text-align:right;">@Html.LabelFor(x => x.UserName)</td> <td style="80%;">@Html.TextBoxFor(x => x.UserName, new { @class = "w3-input w3-border", placeholder = "用户名" })</td> </tr> <tr class="w3-padding"> <td style="vertical-align:middle;text-align:right;">@Html.LabelFor(x => x.Pwd)</td> <td>@Html.PasswordFor(x => x.Pwd, new { @class = "w3-input w3-border", placeholder = "密 码" })</td> </tr> <tr style="display:none;"> <td><input type="text" id="returnUrl" name="returnUrl" value="@Url.Encode(Request.Url.ToString())"/></td> </tr> <tr> <td></td> <td style="text-align:left;"> <div style="30%;"><button type="submit" class="w3-btn-block w3-teal">登录</button></div> </td> </tr> </table> } </div> @*<script> function login() { } </script>*@ </body> </html>
无权限提示页面如下，也就是NoPemission：
@{ Layout = null; } <!DOCTYPE html> <html> <head> <meta name="viewport" content="width=device-width" /> <title>NoPemission</title> </head> <body> <div> 您无权限操作该页面！ </div> </body> </html>
四、创建MyAuthorizeAttribute权限验证类
创建MyAuthorizeAttribute类的目的是需要做身份验证和权限验证所用，通过继承AuthorizeAttribute类来达到目的：
public class MyAuthorizeAttribute : AuthorizeAttribute { //设置是否拥有某些权限的状态码 private int _status = 0; protected override bool AuthorizeCore(HttpContextBase httpContext) {
//切记：一定要在设置_status的方法的第一行初始化该字段，否则会出现问题。因为针对同一Action来说，上一次访问后完成后，下一次不同权限的账户又来访问，如果不初始化该_status字段，那么该_status字段值还是上一次的旧值。
//估计绑定的Action的Controller实例还存在，没有被回收，等到下一次调用该Controller时，就是会激活该Controller实例
_status=0; //判断当前登录的用户 是否已经登录过且身份认证被通过 if (httpContext.User.Identity.IsAuthenticated) { //判断当前的Roles字段是否是空，是空的，则说明该控制器或Action不需要角色权限控制 if (string.IsNullOrWhiteSpace(Roles)) return true; //通过半角逗号去获取一个权限数组 string[] roles = Roles.Split(new string[] { "," }, StringSplitOptions.RemoveEmptyEntries); if (roles.Length <= 0) return true; //找到当前登录的用户 //httpContext.User.Identity.Name就是我们在Login验证登录时候设置的clogin.UserName。设置代码为FormsAuthentication.SetAuthCookie(clogin.UserName, false); UserViewModel user = Data.Data.users.Where(u => u.UserName == httpContext.User.Identity.Name).SingleOrDefault(); //判断当前登录用户是否拥有访问该控制器或Action的权限，如果有，则返回true，可以访问；如果没有，则返回false，需要在OnAuthorization方法中设置该滤过器的Result。 if (roles.Contains(((int)user.Role).ToString())) return true; else { //无角色权限 通过设置_status，可以在OnAuthorization方法中做出相应的判断，并设置相应的filterContext.Result _status = 10; //授权失败 return false; } } //没有登录，则返回false，表明身份认证未通过，程序直接会跳转到登录页面，登录页面可在web.config中设置 // < system.web > // < authentication mode = "Forms" > // < forms loginUrl = "~/Account/Login" timeout = "2" /> // </ authentication > // </ system.web > else return false; } public override void OnAuthorization(AuthorizationContext filterContext) { //执行父类的OnAuthorization方法 base.OnAuthorization(filterContext); //如果当前的_status有状态变化，则返回相应的ActionResult。当前返回的是无权限查看的提示界面。 if (_status == 10) filterContext.Result = new RedirectToRouteResult(new System.Web.Routing.RouteValueDictionary(new { //需要跳转的Controller controller = "Account", //需要跳转的Action action = "NoPemission", //返回的字段说明 returnUrl = filterContext.HttpContext.Request.Url, returnMessage = "您无权限查看！" })); } }
接着将MyAuthorizeAttribute特性类附加到StudentController的Action中，代码如下：
public class StudentController : Controller { //只要登录成功，即可访问 [MyAuthorize] public ActionResult Index() { return View(Data.Data.students); } //需要登录成功，且该用户角色为 1:Admin 3:System 的才可访问 [MyAuthorize(Roles = "1,3")] public ActionResult FindOne(int? id) { return View("Index", Data.Data.students.Where(s => s.ID == id)); } }
五、测试结果
首先我们将该站点的默认页面设置为StudentIndex，设置方法如下：
public class RouteConfig { public static void RegisterRoutes(RouteCollection routes) { routes.IgnoreRoute("{resource}.axd/{*pathInfo}"); routes.MapRoute( name: "Default", url: "{controller}/{action}/{id}", defaults: new { controller = "Student", action = "Index", id = UrlParameter.Optional } ); } }
接着运行程序：
因为站点启动的时候，默认访问的是Student控制器的Index行为方法，但我们在该Index行为方法附加了一个需要授权的特性MyAuthorize。因此，在没有登录之前去访问Index行为方法的话，就会跳转到我们在web.config配置文件中设置的登录地址。因此，第一次出现在我们眼前的是一个登录界面：
当我们输入正确的用户名和密码，并点击“登录”按钮后，就能进入Student控制器的Index行为方法了。如下图所示：
因为我们是用admin账号登录的，该账户的权限是Admin，因此我们也可以访问Student的FindOne行为方法。如下图所示：
接下来让我们点击“退出”，注销权限为Admin的admin账户，改用权限为Normal的normal账户试一下，看能否访问被权限控制的Student的FindOne行为方法。
输入账户名为normal，密码为1的账户信息，并点击“登录”按钮：
因为我们在Account的登录验证方法Login行为方法中标注登录验证成功后，就会跳转到Student的FindOne行为方法，因此只要账户名和密码输入正确就能验证是否能成功访问FindOne。请看如下结果：
果然，因为我们在FindOne方法中标注了只有1(Admin)和3(System)权限才能访问该方法，而Normal不在这些访问权限之内。
由此可见，我们可以通过继承AuthorizeAttribute类轻松地来达到身份验证和授权的目的，如果不在权限之内，就是不让你操作。