如何在ConfigureServices方法中获取IOptions或将IOptions传递给扩展方法？

Question

我正在开发ASP .NET Core Web API 2.1应用程序。

我将JWT身份验证服务添加为静态类中的扩展方法：

 public static class AuthenticationMiddleware
    {
        public static IServiceCollection AddJwtAuthentication(this IServiceCollection services, string issuer, string key)
        {
            services.AddAuthentication(JwtBearerDefaults.AuthenticationScheme)
                .AddJwtBearer(options =>
                {
                    options.TokenValidationParameters = new TokenValidationParameters
                    {
                        // validate the server that created that token
                        ValidateIssuer = true,
                        // ensure that the recipient of the token is authorized to receive it
                        ValidateAudience = true,
                        // check that the token is not expired and that the signing key of the issuer is valid
                        ValidateLifetime = true,
                        // verify that the key used to sign the incoming token is part of a list of trusted keys
                        ValidateIssuerSigningKey = true,
                        ValidIssuer = issuer,
                        ValidAudience = issuer,
                        IssuerSigningKey = new SymmetricSecurityKey(Encoding.UTF8.GetBytes(key))
                    };
                });

            return services;
        }
    }

我在Startup类的ConfigureServices方法中使用的是这样的：

public void ConfigureServices(IServiceCollection services)
        {
            // adding some services here

            services.AddJwtAuthentication(Configuration["Jwt:Issuer"], Configuration["Jwt:Key"]);

            services.AddMvc().SetCompatibilityVersion(CompatibilityVersion.Version_2_1);           
        }

现在，我需要使用IOptions模式从appsettings.json获取JWT身份验证数据

如何在ConfigureServices方法中获取IOptions以将颁发者和密钥传递给扩展方法？或者如何将IOptions传递给扩展方法？

Answer 1

appsettings.json要将数据从绑定到Model，您可以按照以下步骤操作：

1. Appsettings.json内容

   {
   "Logging": {
    "IncludeScopes": false,
    "LogLevel": {
       "Default": "Warning"
          }
    },      
    "JWT": {
         "Issuer": "I",
         "Key": "K"
       }
    }
   

2. JWT选项

   public class JwtOptions
   {
       public string Issuer { get; set; }
       public string Key { get; set; }
    }
   

3. 启动文件

   public void ConfigureServices(IServiceCollection services)
   {
       services.Configure<JwtOptions>(Configuration.GetSection("JWT"));
       var serviceProvider = services.BuildServiceProvider();
       var opt = serviceProvider.GetRequiredService<IOptions<JwtOptions>>().Value;
       services.AddJwtAuthentication(opt.Issuer, opt.Key);
       services.AddMvc();
   }
   

4. JwtOptions直接传递的另一种选择。

   public void ConfigureServices(IServiceCollection services)
   {
       services.Configure<JwtOptions>(Configuration.GetSection("JWT"));
       var serviceProvider = services.BuildServiceProvider();
       var opt = serviceProvider.GetRequiredService<IOptions<JwtOptions>>().Value;
       services.AddJwtAuthentication(opt);
   
       services.AddMvc();
   }
   

5. 更改扩展方式。

   public static IServiceCollection AddJwtAuthentication(this IServiceCollection services, JwtOptions opt)
   

Answer 2

另一种选择是将配置绑定到具有Bind()扩展名的类。（IMO 这是一个比 IOptions 更干净的解决方案）

public class JwtKeys
{
    public string Issuer { get; set; }
    public string Key { get; set; }
}

public void ConfigureServices(IServiceCollection services)
{
    var jwtKeys = new JwtKeys();
    Configuration.GetSection("JWT").Bind(JwtKeys);

    services.AddJwtAuthentication(jwtKeys);
}

public static IServiceCollection AddJwtAuthentication(this IServiceCollection services, JwtKeys jwtKeys)
{....}

然后，如果您需要解决方案中其他地方的 JwtKeys 设置，只需在集合上注册该类并在需要的地方注入它

services.AddSingleton(jwtKeys);