接受的答案(https://stackoverflow.com/a/41348219/4974715)实际上是不可维护的或不合适的，因为“CanReadResource”被用作索赔(但本质上应该是现实中的政策，IMO)。答案的方法在它被使用的方式上是不正确的，因为如果一个动作方法需要许多不同的声明设置，那么有了这个答案，你就必须重复写一些像……

[ClaimRequirement(MyClaimTypes.Permission, "CanReadResource")] 
[ClaimRequirement(MyClaimTypes.AnotherPermision, "AnotherClaimVaue")]
//and etc. on a single action.

所以，想象一下这需要多少编码。理想情况下，“CanReadResource”应该是一种策略，它使用许多声明来确定用户是否可以读取资源。

我所做的是将策略创建为枚举，然后循环遍历并设置需求，就像这样……

services.AddAuthorization(authorizationOptions =>
        {
            foreach (var policyString in Enum.GetNames(typeof(Enumerations.Security.Policy)))
            {
                authorizationOptions.AddPolicy(
                    policyString,
                    authorizationPolicyBuilder => authorizationPolicyBuilder.Requirements.Add(new DefaultAuthorizationRequirement((Enumerations.Security.Policy)Enum.Parse(typeof(Enumerations.Security.Policy), policyWrtString), DateTime.UtcNow)));

      /* Note that thisn does not stop you from 
          configuring policies directly against a username, claims, roles, etc. You can do the usual.
     */
            }
        }); 

DefaultAuthorizationRequirement类看起来像…

public class DefaultAuthorizationRequirement : IAuthorizationRequirement
{
    public Enumerations.Security.Policy Policy {get; set;} //This is a mere enumeration whose code is not shown.
    public DateTime DateTimeOfSetup {get; set;} //Just in case you have to know when the app started up. And you may want to log out a user if their profile was modified after this date-time, etc.
}

public class DefaultAuthorizationHandler : AuthorizationHandler<DefaultAuthorizationRequirement>
{
    private IAServiceToUse _aServiceToUse;

    public DefaultAuthorizationHandler(
        IAServiceToUse aServiceToUse
        )
    {
        _aServiceToUse = aServiceToUse;
    }

    protected async override Task HandleRequirementAsync(AuthorizationHandlerContext context, DefaultAuthorizationRequirement requirement)
    {
        /*Here, you can quickly check a data source or Web API or etc. 
           to know the latest date-time of the user's profile modification...
        */
        if (_aServiceToUse.GetDateTimeOfLatestUserProfileModication > requirement.DateTimeOfSetup)
        {
            context.Fail(); /*Because any modifications to user information, 
            e.g. if the user used another browser or if by Admin modification, 
            the claims of the user in this session cannot be guaranteed to be reliable.
            */
            return;
        }

        bool shouldSucceed = false; //This should first be false, because context.Succeed(...) has to only be called if the requirement specifically succeeds.

        bool shouldFail = false; /*This should first be false, because context.Fail() 
        doesn't have to be called if there's no security breach.
        */

        // You can do anything.
        await doAnythingAsync();

       /*You can get the user's claims... 
          ALSO, note that if you have a way to priorly map users or users with certain claims 
          to particular policies, add those policies as claims of the user for the sake of ease. 
          BUT policies that require dynamic code (e.g. checking for age range) would have to be 
          coded in the switch-case below to determine stuff.
       */

        var claims = context.User.Claims;

        // You can, of course, get the policy that was hit...
        var policy = requirement.Policy

        //You can use a switch case to determine what policy to deal with here...
        switch (policy)
        {
            case Enumerations.Security.Policy.CanReadResource:
                 /*Do stuff with the claims and change the 
                     value of shouldSucceed and/or shouldFail.
                */
                 break;
            case Enumerations.Security.Policy.AnotherPolicy:
                 /*Do stuff with the claims and change the 
                    value of shouldSucceed and/or shouldFail.
                 */
                 break;
                // Other policies too.

            default:
                 throw new NotImplementedException();
        }

        /* Note that the following conditions are 
            so because failure and success in a requirement handler 
            are not mutually exclusive. They demand certainty.
        */

        if (shouldFail)
        {
            context.Fail(); /*Check the docs on this method to 
            see its implications.
            */
        }                

        if (shouldSucceed)
        {
            context.Succeed(requirement); 
        } 
     }
}

Note that the code above can also enable pre-mapping of a user to a policy in your data store. So, when composing claims for the user, you basically retrieve the policies that had been pre-mapped to the user directly or indirectly (e.g. because the user has a certain claim value and that claim value had been identified and mapped to a policy, such that it provides automatic mapping for users who have that claim value too), and enlist the policies as claims, such that in the authorization handler, you can simply check if the user's claims contain requirement.Policy as a Value of a Claim item in their claims. That is for a static way of satisfying a policy requirement, e.g. "First name" requirement is quite static in nature. So, for the example above (which I had forgotten to give example on Authorize attribute in my earlier updates to this answer), using the policy with Authorize attribute is like as follows, where ViewRecord is an enum member:

[Authorize(Policy = nameof(Enumerations.Security.Policy.ViewRecord))] 

动态需求可以是关于检查年龄范围等，使用这种需求的策略不能预先映射到用户。

一个动态策略索赔检查的例子(例如，检查用户是否超过18岁)已经在@blowdart (https://stackoverflow.com/a/31465227/4974715)给出的答案中。

PS:这是我用手机打出来的。请原谅任何拼写错误和缺乏格式。

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";
}

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()
    {

    }

这里很多人已经说过了，但是有了策略处理程序，你就可以在。net框架中使用旧方法实现的功能而言，你可以走得更远。

我在SO网站上快速写了一个答案:https://stackoverflow.com/a/61963465/7081176 对我来说，在制作了一些类后，它完美地工作了:

EditUserRequirement:

public class EditUserRequirement : IAuthorizationRequirement
{
    public EditUserRequirement()
    {
    }
}

一个抽象处理程序，使我的生活更容易:

public abstract class AbstractRequirementHandler<T> : IAuthorizationHandler
    where T : IAuthorizationRequirement
{
    public async Task HandleAsync(AuthorizationHandlerContext context)
    {
        var pendingRequirements = context.PendingRequirements.ToList();
        foreach (var requirement in pendingRequirements)
        {
            if (requirement is T typedRequirement)
            {
                await HandleRequirementAsync(context, typedRequirement);
            }
        }
    }

    protected abstract Task HandleRequirementAsync(AuthorizationHandlerContext context, T requirement);
}

抽象处理程序的实现:

public class EditUserRequirementHandler : AbstractRequirementHandler<EditUserRequirement>
{
    protected override Task HandleRequirementAsync(AuthorizationHandlerContext context, EditUserRequirement requirement)
    {
        // If the user is owner of the resource, allow it.
        if (IsOwner(context.User, g))
        {
            context.Succeed(requirement);
        }

        return Task.CompletedTask;
    }

    private static bool IsOwner(ClaimsPrincipal user, Guid userIdentifier)
    {
        return user.GetUserIdentifier() == userIdentifier;
    }
}

注册我的处理程序和需求: 服务。AddSingleton < IAuthorizationHandler, EditUserRequirementHandler > ();

        services.AddAuthorization(options =>
        {
            options.AddPolicy(Policies.Policies.EditUser, policy =>
            {
                policy.Requirements.Add(new EditUserRequirement());
            });
        });

然后使用我在Blazor的策略:

<AuthorizeView Policy="@Policies.EditUser" Resource="@id">
    <NotAuthorized>
        <Unauthorized />
    </NotAuthorized>
    <Authorized Context="Auth">
        ...
    </Authorized>
</AuthorizeView>

我希望这对面临这个问题的人有用。

下面的代码适合我在。net Core 5中使用

[AttributeUsage(AttributeTargets.Class | AttributeTargets.Method)]
public class AccessAuthorizationAttribute : AuthorizeAttribute, IAuthorizationFilter
{
    public string Module { get; set; } //Permission string to get from controller

    public AccessAuthorizationAttribute(string module)
    {
        Module = module;
    }
    public void OnAuthorization(AuthorizationFilterContext context)
    {
        //Validate if any permissions are passed when using attribute at controller or action level

        if (string.IsNullOrEmpty(Module))
        {
            //Validation cannot take place without any permissions so returning unauthorized
            context.Result = new UnauthorizedResult();
            return;
        }
       
        if (hasAccess)
        {
            return;
        }

        context.Result = new UnauthorizedResult();
        return;
    }
}

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?