如何使用一个服务来配置另一个服务？

Question

我正在我的应用程序中使用 JwtBearer 配置 AuthenticationService 。

我将 JWT 配置抽象为服务，以便在整个应用程序中使用它。这就是我的代码。

builder.Services.AddSingleton<JWTService>();

builder.Services.AddAuthorization(options =>
{   
    options.AddPolicy("UserPolicy", p => p.RequireAuthenticatedUser().RequireClaim("Profession"));
});
builder.Services.AddAuthentication(x =>
{
    x.DefaultAuthenticateScheme = JwtBearerDefaults.AuthenticationScheme;
    x.DefaultChallengeScheme = JwtBearerDefaults.AuthenticationScheme;
}).AddJwtBearer(options =>
{
    options.TokenValidationParameters = ...;
});

public class JWTService
{
    private IConfiguration _configuration;

    public JWTService(IConfiguration configuration)
    {
        _configuration = configuration;
    }

    public TokenValidationParameters Config()
    {
        return new TokenValidationParameters()
        {
            ValidateActor = true,
            ValidateAudience = true,
            ValidateLifetime = true,
            ValidateIssuerSigningKey = true,
            ClockSkew = TimeSpan.Zero,
            ValidAudience = _configuration["JwtBearerTokenSettings:Audience"],
            ValidIssuer = _configuration["JwtBearerTokenSettings:Issuer"],
            IssuerSigningKey = new SymmetricSecurityKey(Encoding.UTF8.GetBytes(_configuration["JwtBearerTokenSettings:SecretKey"]))
        };
    }
}

那么，如何通过 Config 方法让 JWTService 将其用作 AddJwtBearer 的参数？ 我设法使用 builder.Services.BuildServiceProvider().GetServices 来做到这一点，但我读到不建议这样做。 还有别的办法吗？

Answer 1

您应该能够添加一个委托，该委托将在服务解析时被调用，然后还可以拥有您需要的其他服务，例如提供给它的

IConfiguration

，以便您可以在使用选项之前动态配置选项：

builder.Services.AddAuthorization(options =>
{
    options.AddPolicy("UserPolicy", p => p.RequireAuthenticatedUser().RequireClaim("Profession"));
});
builder.Services.AddAuthentication(x =>
{
    x.DefaultAuthenticateScheme = JwtBearerDefaults.AuthenticationScheme;
    x.DefaultChallengeScheme = JwtBearerDefaults.AuthenticationScheme;
}).AddJwtBearer();

builder.Services
    .AddOptions<JwtBearerOptions>(JwtBearerDefaults.AuthenticationScheme)
    .Configure<IConfiguration>((options, configuration) =>
    {
        options.TokenValidationParameters = new TokenValidationParameters()
        {
            ValidateActor = true,
            ValidateAudience = true,
            ValidateLifetime = true,
            ValidateIssuerSigningKey = true,
            ClockSkew = TimeSpan.Zero,
            ValidAudience = configuration["JwtBearerTokenSettings:Audience"],
            ValidIssuer = configuration["JwtBearerTokenSettings:Issuer"],
            IssuerSigningKey = new SymmetricSecurityKey(Encoding.UTF8.GetBytes(configuration["JwtBearerTokenSettings:SecretKey"])),
        };
    });