Intro#

最近对我们的服务进行了改造，原本内部服务在内部可以匿名调用，现在增加了限制，通过 identity server 来管理 api 和 client，网关和需要访问api的客户端或api服务相互调用通过 client_credencial 的方式来调用，这样一来我们可以清晰知道哪些 api 服务会被哪些 api/client 所调用，而且安全性来说更好。
为了保持后端服务的代码更好的兼容性，希望能够实现相同的代码通过在 Startup 里不同的配置实现不同的 Authorization 逻辑，原来我们的服务的 Authorize 都是以 Authorize("policyName") 的形式来写的，这样一来我们只需要修改这个 Policy 的授权配置就可以了。对于 AllowAnonymous 就希望可以通过一种类似的方式来实现，通过自定义一个 Policy 来实现自己的逻辑

实现方式#

将 action 上的 AllowAnonymous 替换为 Authorize("policyName")，在没有设置 Authorize的 controller 上增加 Authorize("policyName")

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public class AllowAnonymousPolicyTransformer : IApplicationModelConvention {     private readonly string _policyName;      public AllowAnonymousPolicyTransformer() : this("anonymous")     {     }      public AllowAnonymousPolicyTransformer(string policyName) => _policyName = policyName;      public void Apply(ApplicationModel application)     {         foreach (var controllerModel in application.Controllers)         {             if (controllerModel.Filters.Any(_ => _.GetType() == typeof(AuthorizeFilter)))             {                 foreach (var actionModel in controllerModel.Actions)                 {                     if (actionModel.Filters.Any(_ => _.GetType() == typeof(AllowAnonymousFilter)))                     {                         var allowAnonymousFilter = actionModel.Filters.First(_ => _.GetType() == typeof(AllowAnonymousFilter));                         actionModel.Filters.Remove(allowAnonymousFilter);                         actionModel.Filters.Add(new AuthorizeFilter(_policyName));                     }                 }             }             else             {                 if (controllerModel.Filters.Any(_ => _.GetType() == typeof(AllowAnonymousFilter)))                 {                     var allowAnonymousFilter = controllerModel.Filters.First(_ => _.GetType() == typeof(AllowAnonymousFilter));                     controllerModel.Filters.Remove(allowAnonymousFilter);                 }                 controllerModel.Filters.Add(new AuthorizeFilter(_policyName));             }         }     } }  public static class MvcBuilderExtensions {     public static IMvcBuilder AddAnonymousPolicyTransformer(this IMvcBuilder builder)     {         builder.Services.Configure<MvcOptions>(options =>         {             options.Conventions.Insert(0, new AllowAnonymousPolicyTransformer());         });         return builder;     }      public static IMvcBuilder AddAnonymousPolicyTransformer(this IMvcBuilder builder, string policyName)     {         builder.Services.Configure<MvcOptions>(options =>         {             options.Conventions.Insert(0, new AllowAnonymousPolicyTransformer(policyName));         });         return builder;     } }

controller 中的代码：

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