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。

我在静态类中添加了 JWT 认证服务作为扩展方法：

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 方法中使用如下：

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

对于从appsettings.json 到Model 的绑定数据，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.cs

   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. 直接传递JwtOptions 的另一个选项。

   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. 更改扩展方法。

   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，如果您需要在解决方案中的其他位置设置 JwtKeys，只需在集合上注册该类并在需要的地方注入它

services.AddSingleton(jwtKeys);

Answer 3

您可以像这样在 Startup 类中将选项添加到 DI 容器：

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

}

public void ConfigureService(IServiceCollection services)
{
    services.AddOptions();
    services.Configure<JwtOptions>(Configuration.GetSection("Jwt"));
}

现在您可以在配置阶段或扩展方法中使用此选项：

public void Configure(IApplicationBuilder app)
{
    var options = app.ApplicationServices.GetService<IOptions<JwtOptions>();
    // write your own code
}