在ASP.NET MVC中重定向未经授权的控制器

小编典典

在ASP.NET MVC中重定向未经授权的控制器

我在ASP.NET MVC中有一个控制器，但仅限于管理员角色：

[Authorize(Roles = "Admin")]
public class TestController : Controller
{
   ...

如果没有管理员角色的用户导航到该控制器，则会看到空白屏幕。

我想做的就是将他们重定向到View，上面写着“您必须具有管理员角色才能访问此资源”。

我想到的一种方法是检查IsUserInRole（）上的每个操作方法，如果不起作用，则返回此信息视图。但是，我必须将其放入每个会破坏DRY原理并且很麻烦维护的Action中。

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2020-05-19

共1个答案

小编典典

创建基于AuthorizeAttribute的自定义授权属性，并覆盖OnAuthorization来执行检查操作的方式。通常，如果授权检查失败，则AuthorizeAttribute会将过滤结果设置为HttpUnauthorizedResult。您可以将其设置为（错误视图的）ViewResult。

编辑：我有几个博客文章，将更详细地介绍：

例：

    [AttributeUsage( AttributeTargets.Class | AttributeTargets.Method, Inherited = true, AllowMultiple = false )]
    public class MasterEventAuthorizationAttribute : AuthorizeAttribute
    {
        /// <summary>
        /// The name of the master page or view to use when rendering the view on authorization failure.  Default
        /// is null, indicating to use the master page of the specified view.
        /// </summary>
        public virtual string MasterName { get; set; }

        /// <summary>
        /// The name of the view to render on authorization failure.  Default is "Error".
        /// </summary>
        public virtual string ViewName { get; set; }

        public MasterEventAuthorizationAttribute()
            : base()
        {
            this.ViewName = "Error";
        }

        protected void CacheValidateHandler( HttpContext context, object data, ref HttpValidationStatus validationStatus )
        {
            validationStatus = OnCacheAuthorization( new HttpContextWrapper( context ) );
        }

        public override void OnAuthorization( AuthorizationContext filterContext )
        {
            if (filterContext == null)
            {
                throw new ArgumentNullException( "filterContext" );
            }

            if (AuthorizeCore( filterContext.HttpContext ))
            {
                SetCachePolicy( filterContext );
            }
            else if (!filterContext.HttpContext.User.Identity.IsAuthenticated)
            {
                // auth failed, redirect to login page
                filterContext.Result = new HttpUnauthorizedResult();
            }
            else if (filterContext.HttpContext.User.IsInRole( "SuperUser" ))
            {
                // is authenticated and is in the SuperUser role
                SetCachePolicy( filterContext );
            }
            else
            {
                ViewDataDictionary viewData = new ViewDataDictionary();
                viewData.Add( "Message", "You do not have sufficient privileges for this operation." );
                filterContext.Result = new ViewResult { MasterName = this.MasterName, ViewName = this.ViewName, ViewData = viewData };
            }

        }

        protected void SetCachePolicy( AuthorizationContext filterContext )
        {
            // ** IMPORTANT **
            // Since we're performing authorization at the action level, the authorization code runs
            // after the output caching module. In the worst case this could allow an authorized user
            // to cause the page to be cached, then an unauthorized user would later be served the
            // cached page. We work around this by telling proxies not to cache the sensitive page,
            // then we hook our custom authorization code into the caching mechanism so that we have
            // the final say on whether a page should be served from the cache.
            HttpCachePolicyBase cachePolicy = filterContext.HttpContext.Response.Cache;
            cachePolicy.SetProxyMaxAge( new TimeSpan( 0 ) );
            cachePolicy.AddValidationCallback( CacheValidateHandler, null /* data */);
        }


    }

2020-05-19