内容简介:使用
ASP.NET Core MVC
提供了基于角色( Role
)、声明( Chaim
) 和策略 ( Policy
) 等的授权方式。在实际应用中,可能采用部门( Department
, 本文采用用户组 Group
)、职位 ( 可继续沿用 Role
)、权限( Permission
)的方式进行授权。要达到这个目的,仅仅通过自定义 IAuthorizationPolicyProvider
是不行的。本文通过自定义 IApplicationModelProvide
进行扩展。
二、PermissionAuthorizeAttribute : IPermissionAuthorizeData
AuthorizeAttribute
类实现了 IAuthorizeData
接口:
namespace Microsoft.AspNetCore.Authorization { /// <summary> /// Defines the set of data required to apply authorization rules to a resource. /// </summary> public interface IAuthorizeData { /// <summary> /// Gets or sets the policy name that determines access to the resource. /// </summary> string Policy { get; set; } /// <summary> /// Gets or sets a comma delimited list of roles that are allowed to access the resource. /// </summary> string Roles { get; set; } /// <summary> /// Gets or sets a comma delimited list of schemes from which user information is constructed. /// </summary> string AuthenticationSchemes { get; set; } } }
使用 AuthorizeAttribute
不外乎如下几种形式:
[Authorize] [Authorize("SomePolicy")] [Authorize(Roles = "角色1,角色2")] [Authorize(AuthenticationSchemes = JwtBearerDefaults.AuthenticationScheme)]
当然,参数还可以组合起来。另外, Roles
和 AuthenticationSchemes
的值以半角逗号分隔,是 Or
的关系;多个 Authorize
是 And
的关系; Policy
、 Roles
和 AuthenticationSchemes
如果同时使用,也是 And
的关系。
如果要扩展 AuthorizeAttribute
,先扩展 IAuthorizeData
增加新的属性:
public interface IPermissionAuthorizeData : IAuthorizeData { string Groups { get; set; } string Permissions { get; set; } }
然后定义 AuthorizeAttribute:
[AttributeUsage(AttributeTargets.Class | AttributeTargets.Method, AllowMultiple = true, Inherited = true)] public class PermissionAuthorizeAttribute : Attribute, IPermissionAuthorizeData { public string Policy { get; set; } public string Roles { get; set; } public string AuthenticationSchemes { get; set; } public string Groups { get; set; } public string Permissions { get; set; } }
现在,在 Controller
或 Action
上就可以这样使用了:
[PermissionAuthorize(Roles = "经理,副经理")] // 经理或副经理 [PermissionAuthorize(Groups = "研发部,生产部", Roles = "经理"] // 研发部经理或生成部经理。Groups 和 Roles 是 `And` 的关系。 [PermissionAuthorize(Groups = "研发部,生产部", Roles = "经理", Permissions = "请假审批"] // 研发部经理或生产部经理,并且有请假审批的权限。Groups 、Roles 和 Permissions 是 `And` 的关系。
数据已经准备好,下一步就是怎么提取出来。通过扩展 AuthorizationApplicationModelProvider
来实现。
三、PermissionAuthorizationApplicationModelProvider : IApplicationModelProvider
AuthorizationApplicationModelProvider
类的作用是构造 AuthorizeFilter
对象放入 ControllerModel
或 ActionModel
的 Filters
属性中。具体过程是先提取 Controller
和 Action
实现了 IAuthorizeData
接口的 Attribute
,如果使用的是默认的 DefaultAuthorizationPolicyProvider
,则会先创建一个 AuthorizationPolicy
对象作为 AuthorizeFilter
构造函数的参数。
创建 AuthorizationPolicy
对象是由 AuthorizationPolicy
的静态方法 public static async Task<AuthorizationPolicy> CombineAsync(IAuthorizationPolicyProvider policyProvider, IEnumerable<IAuthorizeData> authorizeData)
来完成的。该静态方法会解析 IAuthorizeData
的数据,但不懂解析 IPermissionAuthorizeData
。
因为 AuthorizationApplicationModelProvider
类对 AuthorizationPolicy.CombineAsync
静态方法有依赖,这里不得不做一个类似的 PermissionAuthorizationApplicationModelProvider
类,在本类实现 CombineAsync
方法。暂且不论该方法放在本类是否合适的问题。
public static AuthorizeFilter GetFilter(IAuthorizationPolicyProvider policyProvider, IEnumerable<IAuthorizeData> authData) { // The default policy provider will make the same policy for given input, so make it only once. // This will always execute synchronously. if (policyProvider.GetType() == typeof(DefaultAuthorizationPolicyProvider)) { var policy = CombineAsync(policyProvider, authData).GetAwaiter().GetResult(); return new AuthorizeFilter(policy); } else { return new AuthorizeFilter(policyProvider, authData); } } private static async Task<AuthorizationPolicy> CombineAsync(IAuthorizationPolicyProvider policyProvider, IEnumerable<IAuthorizeData> authorizeData) { if (policyProvider == null) { throw new ArgumentNullException(nameof(policyProvider)); } if (authorizeData == null) { throw new ArgumentNullException(nameof(authorizeData)); } var policyBuilder = new AuthorizationPolicyBuilder(); var any = false; foreach (var authorizeDatum in authorizeData) { any = true; var useDefaultPolicy = true; if (!string.IsNullOrWhiteSpace(authorizeDatum.Policy)) { var policy = await policyProvider.GetPolicyAsync(authorizeDatum.Policy); if (policy == null) { //throw new InvalidOperationException(Resources.FormatException_AuthorizationPolicyNotFound(authorizeDatum.Policy)); throw new InvalidOperationException(nameof(authorizeDatum.Policy)); } policyBuilder.Combine(policy); useDefaultPolicy = false; } var rolesSplit = authorizeDatum.Roles?.Split(','); if (rolesSplit != null && rolesSplit.Any()) { var trimmedRolesSplit = rolesSplit.Where(r => !string.IsNullOrWhiteSpace(r)).Select(r => r.Trim()); policyBuilder.RequireRole(trimmedRolesSplit); useDefaultPolicy = false; } if(authorizeDatum is IPermissionAuthorizeData permissionAuthorizeDatum ) { var groupsSplit = permissionAuthorizeDatum.Groups?.Split(','); if (groupsSplit != null && groupsSplit.Any()) { var trimmedGroupsSplit = groupsSplit.Where(r => !string.IsNullOrWhiteSpace(r)).Select(r => r.Trim()); policyBuilder.RequireClaim("Group", trimmedGroupsSplit); // TODO: 注意硬编码 useDefaultPolicy = false; } var permissionsSplit = permissionAuthorizeDatum.Permissions?.Split(','); if (permissionsSplit != null && permissionsSplit.Any()) { var trimmedPermissionsSplit = permissionsSplit.Where(r => !string.IsNullOrWhiteSpace(r)).Select(r => r.Trim()); policyBuilder.RequireClaim("Permission", trimmedPermissionsSplit);// TODO: 注意硬编码 useDefaultPolicy = false; } } var authTypesSplit = authorizeDatum.AuthenticationSchemes?.Split(','); if (authTypesSplit != null && authTypesSplit.Any()) { foreach (var authType in authTypesSplit) { if (!string.IsNullOrWhiteSpace(authType)) { policyBuilder.AuthenticationSchemes.Add(authType.Trim()); } } } if (useDefaultPolicy) { policyBuilder.Combine(await policyProvider.GetDefaultPolicyAsync()); } } return any ? policyBuilder.Build() : null; }
if(authorizeDatum is IPermissionAuthorizeData permissionAuthorizeDatum )
为扩展部分。
四、Startup
注册 PermissionAuthorizationApplicationModelProvider
服务,需要在 AddMvc
之后替换掉 AuthorizationApplicationModelProvider
服务。
services.AddMvc(); services.Replace(ServiceDescriptor.Transient<IApplicationModelProvider,PermissionAuthorizationApplicationModelProvider>());
五、Jwt 示例
[Route("api/[controller]")] [ApiController] public class ValuesController : ControllerBase { private readonly JwtSecurityTokenHandler _tokenHandler = new JwtSecurityTokenHandler(); [HttpGet] [Route("SignIn")] public async Task<ActionResult<string>> SignIn() { var user = new ClaimsPrincipal(new ClaimsIdentity(new[] { // 备注:Claim Type: Group 和 Permission 这里使用的是硬编码,应该定义为类似于 ClaimTypes.Role 的常量;另外,下列模拟数据不一定合逻辑。 new Claim(ClaimTypes.Name, "Bob"), new Claim(ClaimTypes.Role, "经理"), // 注意:不能使用逗号分隔来达到多个角色的目的,下同。 new Claim(ClaimTypes.Role, "副经理"), new Claim("Group", "研发部"), new Claim("Group", "生产部"), new Claim("Permission", "请假审批"), new Claim("Permission", "权限1"), new Claim("Permission", "权限2"), }, JwtBearerDefaults.AuthenticationScheme)); var token = new JwtSecurityToken( "SignalRAuthenticationSample", "SignalRAuthenticationSample", user.Claims, expires: DateTime.UtcNow.AddDays(30), signingCredentials: SignatureHelper.GenerateSigningCredentials("1234567890123456")); return _tokenHandler.WriteToken(token); } [HttpGet] [Route("Test")] [PermissionAuthorize(Groups = "研发部,生产部", Roles = "经理", Permissions = "请假审批"] // 研发部经理或生成部经理,并且有请假审批的权限。Groups 、Roles 和 Permission 是 `And` 的关系。 public async Task<ActionResult<IEnumerable<string>>> Test() { var user = HttpContext.User; return new string[] { "value1", "value2" }; } }
六、问题
AuthorizeFilter
类显示实现了 IFilterFactory
接口的 CreateInstance
方法:
IFilterMetadata IFilterFactory.CreateInstance(IServiceProvider serviceProvider) { if (Policy != null || PolicyProvider != null) { // The filter is fully constructed. Use the current instance to authorize. return this; } Debug.Assert(AuthorizeData != null); var policyProvider = serviceProvider.GetRequiredService<IAuthorizationPolicyProvider>(); return AuthorizationApplicationModelProvider.GetFilter(policyProvider, AuthorizeData); }
竟然对 AuthorizationApplicationModelProvider.GetFilter
静态方法产生了依赖。庆幸的是,如果通过 AuthorizeFilter(IAuthorizationPolicyProvider policyProvider, IEnumerable<IAuthorizeData> authorizeData)
或 AuthorizeFilter(AuthorizationPolicy policy)
创建 AuthorizeFilter
对象不会产生什么不良影响。
七、下一步
[PermissionAuthorize(Groups = "研发部,生产部", Roles = "经理", Permissions = "请假审批"]
这种形式还是不够灵活,哪怕用多个 Attribute
, And
和 Or
的逻辑组合不一定能满足需求。可以在 IPermissionAuthorizeData
新增一个 Rule
属性,实现类似的效果:
[PermissionAuthorize(Rule = "(Groups:研发部,生产部)&&(Roles:请假审批||Permissions:超级权限)"]
通过 Rule
计算复杂的授权。
八、如何通过自定义 IAuthorizationPolicyProvider 实现?
另一种方式是自定义 IAuthorizationPolicyProvider
,不过还需要自定义 AuthorizeFilter
。因为当不是使用 DefaultAuthorizationPolicyProvider
而是自定义 IAuthorizationPolicyProvider
时, AuthorizationApplicationModelProvider
(或前文定义的 PermissionAuthorizationApplicationModelProvider
)会使用 AuthorizeFilter(IAuthorizationPolicyProvider policyProvider, IEnumerable<IAuthorizeData> authorizeData)
创建 AuthorizeFilter
对象,而不是 AuthorizeFilter(AuthorizationPolicy policy)
。这会造成 AuthorizeFilter
对象在 OnAuthorizationAsync
时会间接调用 AuthorizationPolicy.CombineAsync
静态方法。
这可以说是一个设计上的缺陷,不应该让 AuthorizationPolicy.CombineAsync
静态方法存在,哪怕提供个 IAuthorizationPolicyCombiner
也好。另外,上文提到的 AuthorizationApplicationModelProvider.GetFilter
静态方法同样不是一种好的设计。等微软想通吧。
以上就是本文的全部内容,希望本文的内容对大家的学习或者工作能带来一定的帮助,也希望大家多多支持 码农网
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