什么? !

我决定再补充一个简单的答案。B/c我发现大多数答案都有点过度设计。也因为我需要一种授予授权的方法，而不仅仅是否认它。这里的大多数答案都提供了一种“加强”安全性的方法，但我想“放松”它。例如:“如果配置了某些应用程序设置，则允许匿名用户访问”。

public class MyAuthAttribute : Attribute, IAuthorizationFilter
{
    public void OnAuthorization(AuthorizationFilterContext context)
    {
        //check access 
        if (CheckPermissions())
        {
            //all good, add optional code if you want. Or don't
        }
        else
        {
            //DENIED!
            //return "ChallengeResult" to redirect to login page (for example)
            context.Result = new ChallengeResult(CookieAuthenticationDefaults.AuthenticationScheme);
        }
    }
}

就是这样。不需要混淆“策略”，“声明”，“处理程序”和其他[哔]

用法:

// GET api/Get/5
[MyAuth]
public ActionResult<string> Get(int id)
{
    return "blahblah";
}

ASP。Net Core团队将使用这里完整记录的新策略设计。新方法背后的基本思想是使用新的[Authorize]属性来指定一个“策略”(例如[Authorize(policy = "YouNeedToBe18ToDoThis")]，其中策略在应用程序的Startup.cs中注册，以执行一些代码块(即确保用户在年龄为18岁或以上时有年龄声明)。

The policy design is a great addition to the framework and the ASP.Net Security Core team should be commended for its introduction. That said, it isn't well-suited for all cases. The shortcoming of this approach is that it fails to provide a convenient solution for the most common need of simply asserting that a given controller or action requires a given claim type. In the case where an application may have hundreds of discrete permissions governing CRUD operations on individual REST resources ("CanCreateOrder", "CanReadOrder", "CanUpdateOrder", "CanDeleteOrder", etc.), the new approach either requires repetitive one-to-one mappings between a policy name and a claim name (e.g. options.AddPolicy("CanUpdateOrder", policy => policy.RequireClaim(MyClaimTypes.Permission, "CanUpdateOrder));), or writing some code to perform these registrations at run time (e.g. read all claim types from a database and perform the aforementioned call in a loop). The problem with this approach for the majority of cases is that it's unnecessary overhead.

而ASP。Net Core Security团队建议永远不要创建自己的解决方案，在某些情况下，这可能是最谨慎的选择。

下面是一个实现，它使用IAuthorizationFilter提供了一种简单的方式来表达给定控制器或动作的索赔要求:

public class ClaimRequirementAttribute : TypeFilterAttribute
{
    public ClaimRequirementAttribute(string claimType, string claimValue) : base(typeof(ClaimRequirementFilter))
    {
        Arguments = new object[] {new Claim(claimType, claimValue) };
    }
}

public class ClaimRequirementFilter : IAuthorizationFilter
{
    readonly Claim _claim;

    public ClaimRequirementFilter(Claim claim)
    {
        _claim = claim;
    }

    public void OnAuthorization(AuthorizationFilterContext context)
    {
        var hasClaim = context.HttpContext.User.Claims.Any(c => c.Type == _claim.Type && c.Value == _claim.Value);
        if (!hasClaim)
        {
            context.Result = new ForbidResult();
        }
    }
}


[Route("api/resource")]
public class MyController : Controller
{
    [ClaimRequirement(MyClaimTypes.Permission, "CanReadResource")]
    [HttpGet]
    public IActionResult GetResource()
    {
        return Ok();
    }
}

当前制作自定义AuthorizeAttribute的方法是什么

对于纯授权场景(例如仅限制特定用户访问)，建议使用新的授权块:https://github.com/aspnet/MusicStore/blob/1c0aeb08bb1ebd846726232226279bbe001782e1/samples/MusicStore/Startup.cs#L84-L92

public class Startup
{
    public void ConfigureServices(IServiceCollection services)
    {
        services.Configure<AuthorizationOptions>(options =>
        {
            options.AddPolicy("ManageStore", policy => policy.RequireClaim("Action", "ManageStore"));
        });
    }
}

public class StoreController : Controller
{
    [Authorize(Policy = "ManageStore"), HttpGet]
    public async Task<IActionResult> Manage() { ... }
}

对于身份验证，最好在中间件级别进行处理。

你到底想达到什么目的?

为了在我们的应用程序中进行授权。我们必须根据在授权属性中传递的参数调用服务。

例如，如果我们想检查登录的医生是否可以查看病人的预约，我们将传递“View_Appointment”到自定义授权属性，并在DB服务中检查该权利，并根据结果进行审查。下面是这个场景的代码:

    public class PatientAuthorizeAttribute : TypeFilterAttribute
    {
    public PatientAuthorizeAttribute(params PatientAccessRights[] right) : base(typeof(AuthFilter)) //PatientAccessRights is an enum
    {
        Arguments = new object[] { right };
    }

    private class AuthFilter : IActionFilter
    {
        PatientAccessRights[] right;

        IAuthService authService;

        public AuthFilter(IAuthService authService, PatientAccessRights[] right)
        {
            this.right = right;
            this.authService = authService;
        }

        public void OnActionExecuted(ActionExecutedContext context)
        {
        }

        public void OnActionExecuting(ActionExecutingContext context)
        {
            var allparameters = context.ActionArguments.Values;
            if (allparameters.Count() == 1)
            {
                var param = allparameters.First();
                if (typeof(IPatientRequest).IsAssignableFrom(param.GetType()))
                {
                    IPatientRequest patientRequestInfo = (IPatientRequest)param;
                    PatientAccessRequest userAccessRequest = new PatientAccessRequest();
                    userAccessRequest.Rights = right;
                    userAccessRequest.MemberID = patientRequestInfo.PatientID;
                    var result = authService.CheckUserPatientAccess(userAccessRequest).Result; //this calls DB service to check from DB
                    if (result.Status == ReturnType.Failure)
                    {
                        //TODO: return apirepsonse
                        context.Result = new StatusCodeResult((int)System.Net.HttpStatusCode.Forbidden);
                    }
                }
                else
                {
                    throw new AppSystemException("PatientAuthorizeAttribute not supported");
                }
            }
            else
            {
                throw new AppSystemException("PatientAuthorizeAttribute not supported");
            }
        }
    }
}

在API操作中，我们像这样使用它:

    [PatientAuthorize(PatientAccessRights.PATIENT_VIEW_APPOINTMENTS)] //this is enum, we can pass multiple
    [HttpPost]
    public SomeReturnType ViewAppointments()
    {

    }

基于Derek Greer伟大的答案，我用枚举来做。

下面是我的代码示例:

public enum PermissionItem
{
    User,
    Product,
    Contact,
    Review,
    Client
}

public enum PermissionAction
{
    Read,
    Create,
}


public class AuthorizeAttribute : TypeFilterAttribute
{
    public AuthorizeAttribute(PermissionItem item, PermissionAction action)
    : base(typeof(AuthorizeActionFilter))
    {
        Arguments = new object[] { item, action };
    }
}

public class AuthorizeActionFilter : IAuthorizationFilter
{
    private readonly PermissionItem _item;
    private readonly PermissionAction _action;
    public AuthorizeActionFilter(PermissionItem item, PermissionAction action)
    {
        _item = item;
        _action = action;
    }
    public void OnAuthorization(AuthorizationFilterContext context)
    {
        bool isAuthorized = MumboJumboFunction(context.HttpContext.User, _item, _action); // :)

        if (!isAuthorized)
        {
            context.Result = new ForbidResult();
        }
    }
}

public class UserController : BaseController
{
    private readonly DbContext _context;

    public UserController( DbContext context) :
        base()
    {
        _logger = logger;
    }

    [Authorize(PermissionItem.User, PermissionAction.Read)]
    public async Task<IActionResult> Index()
    {
        return View(await _context.User.ToListAsync());
    }
}

在写这篇文章时，我相信这可以用asp.net core 2及以上的iclaimstrtransform接口来完成。我刚刚实现了一个概念的证明，可以分享到这里。

public class PrivilegesToClaimsTransformer : IClaimsTransformation
{
    private readonly IPrivilegeProvider privilegeProvider;
    public const string DidItClaim = "http://foo.bar/privileges/resolved";

    public PrivilegesToClaimsTransformer(IPrivilegeProvider privilegeProvider)
    {
        this.privilegeProvider = privilegeProvider;
    }

    public async Task<ClaimsPrincipal> TransformAsync(ClaimsPrincipal principal)
    {
        if (principal.Identity is ClaimsIdentity claimer)
        {
            if (claimer.HasClaim(DidItClaim, bool.TrueString))
            {
                return principal;
            }

            var privileges = await this.privilegeProvider.GetPrivileges( ... );
            claimer.AddClaim(new Claim(DidItClaim, bool.TrueString));

            foreach (var privilegeAsRole in privileges)
            {
                claimer.AddClaim(new Claim(ClaimTypes.Role /*"http://schemas.microsoft.com/ws/2008/06/identity/claims/role" */, privilegeAsRole));
            }
        }

        return principal;
    }
}

要在你的控制器中使用它，只需在你的方法中添加适当的[授权(角色="whatever")]。

[HttpGet]
[Route("poc")]
[Authorize(Roles = "plugh,blast")]
public JsonResult PocAuthorization()
{
    var result = Json(new
    {
        when = DateTime.UtcNow,
    });

    result.StatusCode = (int)HttpStatusCode.OK;

    return result;
}

在我们的例子中，每个请求都包含一个JWT的授权标头。这是原型，我相信下周我们会在我们的生产系统中做一些非常接近的东西。

未来的选民，在投票时，请考虑投票日期。到今天为止，这在我的机器上还能用。您可能需要在实现上进行更多的错误处理和日志记录。