现代的方法是AuthenticationHandlers

在startup.cs中添加

services.AddAuthentication("BasicAuthentication").AddScheme<AuthenticationSchemeOptions, BasicAuthenticationHandler>("BasicAuthentication", null);

public class BasicAuthenticationHandler : AuthenticationHandler<AuthenticationSchemeOptions>
    {
        private readonly IUserService _userService;

        public BasicAuthenticationHandler(
            IOptionsMonitor<AuthenticationSchemeOptions> options,
            ILoggerFactory logger,
            UrlEncoder encoder,
            ISystemClock clock,
            IUserService userService)
            : base(options, logger, encoder, clock)
        {
            _userService = userService;
        }

        protected override async Task<AuthenticateResult> HandleAuthenticateAsync()
        {
            if (!Request.Headers.ContainsKey("Authorization"))
                return AuthenticateResult.Fail("Missing Authorization Header");

            User user = null;
            try
            {
                var authHeader = AuthenticationHeaderValue.Parse(Request.Headers["Authorization"]);
                var credentialBytes = Convert.FromBase64String(authHeader.Parameter);
                var credentials = Encoding.UTF8.GetString(credentialBytes).Split(new[] { ':' }, 2);
                var username = credentials[0];
                var password = credentials[1];
                user = await _userService.Authenticate(username, password);
            }
            catch
            {
                return AuthenticateResult.Fail("Invalid Authorization Header");
            }

            if (user == null)
                return AuthenticateResult.Fail("Invalid User-name or Password");

            var claims = new[] {
                new Claim(ClaimTypes.NameIdentifier, user.Id.ToString()),
                new Claim(ClaimTypes.Name, user.Username),
            };
            var identity = new ClaimsIdentity(claims, Scheme.Name);
            var principal = new ClaimsPrincipal(identity);
            var ticket = new AuthenticationTicket(principal, Scheme.Name);

            return AuthenticateResult.Success(ticket);
        }
    }

IUserService是一个你有用户名和密码的服务。 基本上它返回一个用户类，您可以使用它来映射您的声明。

var claims = new[] {
                new Claim(ClaimTypes.NameIdentifier, user.Id.ToString()),
                new Claim(ClaimTypes.Name, user.Username),
            }; 

然后你可以查询这些索赔和她的任何数据你映射，有相当多，看看ClaimTypes类

您可以在扩展方法中使用它来获取任何映射

public int? GetUserId()
{
   if (context.User.Identity.IsAuthenticated)
    {
       var id=context.User.FindFirst(ClaimTypes.NameIdentifier);
       if (!(id is null) && int.TryParse(id.Value, out var userId))
            return userId;
     }
      return new Nullable<int>();
 }

我认为这种新方法比这里展示的旧方法更好，两种方法都有效

public class BasicAuthenticationAttribute : AuthorizationFilterAttribute
{
    public override void OnAuthorization(HttpActionContext actionContext)
    {
        if (actionContext.Request.Headers.Authorization != null)
        {
            var authToken = actionContext.Request.Headers.Authorization.Parameter;
            // decoding authToken we get decode value in 'Username:Password' format
            var decodeauthToken = System.Text.Encoding.UTF8.GetString(Convert.FromBase64String(authToken));
            // spliting decodeauthToken using ':'
            var arrUserNameandPassword = decodeauthToken.Split(':');
            // at 0th postion of array we get username and at 1st we get password
            if (IsAuthorizedUser(arrUserNameandPassword[0], arrUserNameandPassword[1]))
            {
                // setting current principle
                Thread.CurrentPrincipal = new GenericPrincipal(new GenericIdentity(arrUserNameandPassword[0]), null);
            }
            else
            {
                actionContext.Response = actionContext.Request.CreateResponse(HttpStatusCode.Unauthorized);
            }
        }
        else
        {
            actionContext.Response = actionContext.Request.CreateResponse(HttpStatusCode.Unauthorized);
        }
    }

    public static bool IsAuthorizedUser(string Username, string Password)
    {
        // In this method we can handle our database logic here...
        return Username.Equals("test") && Password == "test";
    }
}

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();
    }
}

您可以创建自己的AuthorizationHandler，它将在控制器和动作上找到自定义属性，并将它们传递给handlerrequirementasync方法。

public abstract class AttributeAuthorizationHandler<TRequirement, TAttribute> : AuthorizationHandler<TRequirement> where TRequirement : IAuthorizationRequirement where TAttribute : Attribute
{
    protected override Task HandleRequirementAsync(AuthorizationHandlerContext context, TRequirement requirement)
    {
        var attributes = new List<TAttribute>();

        var action = (context.Resource as AuthorizationFilterContext)?.ActionDescriptor as ControllerActionDescriptor;
        if (action != null)
        {
            attributes.AddRange(GetAttributes(action.ControllerTypeInfo.UnderlyingSystemType));
            attributes.AddRange(GetAttributes(action.MethodInfo));
        }

        return HandleRequirementAsync(context, requirement, attributes);
    }

    protected abstract Task HandleRequirementAsync(AuthorizationHandlerContext context, TRequirement requirement, IEnumerable<TAttribute> attributes);

    private static IEnumerable<TAttribute> GetAttributes(MemberInfo memberInfo)
    {
        return memberInfo.GetCustomAttributes(typeof(TAttribute), false).Cast<TAttribute>();
    }
}

然后你可以在你的控制器或动作上使用它的任何自定义属性。例如，添加权限要求。只需创建您的自定义属性。

[AttributeUsage(AttributeTargets.Class | AttributeTargets.Method, AllowMultiple = true)]
public class PermissionAttribute : AuthorizeAttribute
{
    public string Name { get; }

    public PermissionAttribute(string name) : base("Permission")
    {
        Name = name;
    }
}

然后创建一个需求，添加到您的策略

public class PermissionAuthorizationRequirement : IAuthorizationRequirement
{
    //Add any custom requirement properties if you have them
}

然后为您的自定义属性创建AuthorizationHandler，继承我们之前创建的AttributeAuthorizationHandler。它将被传递一个IEnumerable，用于handlerrequirementsasync方法中的所有自定义属性，这些属性是由控制器和动作积累而来的。

public class PermissionAuthorizationHandler : AttributeAuthorizationHandler<PermissionAuthorizationRequirement, PermissionAttribute>
{
    protected override async Task HandleRequirementAsync(AuthorizationHandlerContext context, PermissionAuthorizationRequirement requirement, IEnumerable<PermissionAttribute> attributes)
    {
        foreach (var permissionAttribute in attributes)
        {
            if (!await AuthorizeAsync(context.User, permissionAttribute.Name))
            {
                return;
            }
        }

        context.Succeed(requirement);
    }

    private Task<bool> AuthorizeAsync(ClaimsPrincipal user, string permission)
    {
        //Implement your custom user permission logic here
    }
}

最后，在Startup.cs ConfigureServices方法中，将您的自定义AuthorizationHandler添加到服务中，并添加您的Policy。

        services.AddSingleton<IAuthorizationHandler, PermissionAuthorizationHandler>();

        services.AddAuthorization(options =>
        {
            options.AddPolicy("Permission", policyBuilder =>
            {
                policyBuilder.Requirements.Add(new PermissionAuthorizationRequirement());
            });
        });

现在你可以简单地用你的自定义属性装饰你的控制器和动作。

[Permission("AccessCustomers")]
public class CustomersController
{
    [Permission("AddCustomer")]
    IActionResult AddCustomer([FromBody] Customer customer)
    {
        //Add customer
    }
}

我是asp.net安全人员。首先，让我道歉，除了音乐存储样本或单元测试之外，这些都还没有被记录下来，而且还在公开的api方面进行改进。详细的文档在这里。

我们不希望您编写自定义授权属性。如果你需要这样做，我们做错了什么。相反，您应该编写授权需求。

授权作用于身份。身份通过认证创建。

You say in comments you want to check a session ID in a header. Your session ID would be the basis for identity. If you wanted to use the Authorize attribute you'd write an authentication middleware to take that header and turn it into an authenticated ClaimsPrincipal. You would then check that inside an authorization requirement. Authorization requirements can be as complicated as you like, for example here's one that takes a date of birth claim on the current identity and will authorize if the user is over 18;

public class Over18Requirement : AuthorizationHandler<Over18Requirement>, IAuthorizationRequirement
{
  public override void Handle(AuthorizationHandlerContext context, Over18Requirement requirement)
  {
    if (!context.User.HasClaim(c => c.Type == ClaimTypes.DateOfBirth))
    {
      context.Fail();
      return;
    }

    var dobVal = context.User.FindFirst(c => c.Type == ClaimTypes.DateOfBirth).Value;
    var dateOfBirth = Convert.ToDateTime(dobVal);
    int age = DateTime.Today.Year - dateOfBirth.Year;
    if (dateOfBirth > DateTime.Today.AddYears(-age))
    {
      age--;
    }

    if (age >= 18)
    {
      context.Succeed(requirement);
    }
    else
    {
      context.Fail();
    }
  }
}

然后在ConfigureServices()函数中将其连接起来

services.AddAuthorization(options =>
{
    options.AddPolicy("Over18", 
        policy => policy.Requirements.Add(new Authorization.Over18Requirement()));
});

最后，将它应用到控制器或动作方法

[Authorize(Policy = "Over18")]

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。

如果有人只是想在授权阶段使用当前的安全实践验证一个承载令牌，

将此添加到Startup/ConfigureServices中

    services.AddSingleton<IAuthorizationHandler, BearerAuthorizationHandler>();
    services.AddAuthentication(JwtBearerDefaults.AuthenticationScheme).AddJwtBearer();

    services.AddAuthorization(options => options.AddPolicy("Bearer",
        policy => policy.AddRequirements(new BearerRequirement())
        )
    );

在你的代码库中，

public class BearerRequirement : IAuthorizationRequirement
{
    public async Task<bool> IsTokenValid(SomeValidationContext context, string token)
    {
        // here you can check if the token received is valid 
        return true;
    }
}

public class BearerAuthorizationHandler : AuthorizationHandler<BearerRequirement> 
{

    public BearerAuthorizationHandler(SomeValidationContext thatYouCanInject)
    {
       ...
    }

    protected override async Task HandleRequirementAsync(AuthorizationHandlerContext context, BearerRequirement requirement)
    {
        var authFilterCtx = (Microsoft.AspNetCore.Mvc.Filters.AuthorizationFilterContext)context.Resource;
        string authHeader = authFilterCtx.HttpContext.Request.Headers["Authorization"];
        if (authHeader != null && authHeader.Contains("Bearer"))
        {
            var token = authHeader.Replace("Bearer ", string.Empty);
            if (await requirement.IsTokenValid(thatYouCanInject, token))
            {
                context.Succeed(requirement);
            }
        }
    }
}

如果代码没有到达context.Succeed(…)，那么无论如何都会失败(401)。

然后在你的控制器中你可以使用

 [Authorize(Policy = "Bearer", AuthenticationSchemes = JwtBearerDefaults.AuthenticationScheme)]