依赖注入 - 没有给出对应于所需参数的参数

Question

我在 inte.net 上找到了几个 JWT 身份验证的示例代码实现，但我很难让这些代码一起工作（因为我从各种来源获得了这些代码）。

我正在尝试将 JWT 身份验证添加到 Visual Studio 中生成的 WeatherForecast API 项目（Web API）。 以下是我对默认项目所做的更改：

1. 创建一个 JWT 服务 class：创建一个新的 class 来处理创建和验证 JWT。 这个 class 应该有方法来创建 JWT 给定一组声明，并验证 JWT 并返回其中包含的声明。

public class JwtService
{
    private readonly SymmetricSecurityKey _signingKey;

    public JwtService(string secretKey)
    {
        _signingKey = new SymmetricSecurityKey(Encoding.UTF8.GetBytes(secretKey));
    }

    public string CreateToken(ClaimsIdentity claims)
    {
        var jwt = new JwtSecurityToken(
            issuer: "app",
            audience: "app",
            claims: claims.Claims,
            notBefore: DateTime.Now,
            expires: DateTime.Now.AddDays(7),
            signingCredentials: new SigningCredentials(_signingKey, SecurityAlgorithms.HmacSha256)
        );

        return new JwtSecurityTokenHandler().WriteToken(jwt);
    }

    public ClaimsPrincipal GetPrincipalFromToken(string token)
    {
        var tokenValidationParameters = new TokenValidationParameters
        {
            ValidateIssuer = true,
            ValidIssuer = "app",
            ValidateAudience = true,
            ValidAudience = "app",
            ValidateLifetime = true,
            IssuerSigningKey = _signingKey
        };

        var handler = new JwtSecurityTokenHandler();

        try
        {
            var principal = handler.ValidateToken(token, tokenValidationParameters, out var validatedToken);
            return principal;
        }
        catch (SecurityTokenValidationException)
        {
            return null;
        }
    }
}

2. 创建一个 JWT 身份验证服务 class：创建一个新的 class，它将处理用户身份验证并返回 JWT。这个 class 应该有一个方法来验证给定用户名和密码的用户，如果身份验证是 JWT，则返回 JWT。

public class JwtAuthenticationService
{
    private readonly JwtService _jwtService;

    public JwtAuthenticationService(JwtService jwtService)
    {
        _jwtService = jwtService;
    }

    public string Authenticate(string username, string password)
    {
        // authenticate user
        var authenticated = username == "test" && password == "test";

        if (!authenticated)
            return null;

        // create claims
        var claims = new ClaimsIdentity(new[]
        {
                new Claim(ClaimTypes.Name, username),
                new Claim(ClaimTypes.Role, "User")
            });

        // create token
        return _jwtService.CreateToken(claims);
    }
}

3. 创建一个 JWT 授权过滤器：创建一个新的 class，它将处理检查请求是否包含有效的 JWT，如果包含，则将 JWT 中包含的声明添加到当前用户的声明中。

public class JwtAuthorizationFilter : AuthorizationFilterAttribute
{
    private readonly JwtService _jwtService;

    public JwtAuthorizationFilter(JwtService jwtService)
    {
        _jwtService = jwtService;
    }

    public void OnAuthorization(AuthorizationFilterContext context)
    {
        // check if the request contains an Authorization header
        var authHeader = context.HttpContext.Request.Headers["Authorization"].FirstOrDefault();

        if (authHeader == null || !authHeader.StartsWith("Bearer "))
        {
            context.Result = new UnauthorizedResult();
            return;
        }

        // get the token from the header
        var token = authHeader.Substring("Bearer ".Length).Trim();
        // validate the token and get the claims
        var claimsPrincipal = _jwtService.GetPrincipalFromToken(token);

        if (claimsPrincipal == null)
        {
            context.Result = new UnauthorizedResult();
            return;
        }

        // set the current user's claims
        var identity = (ClaimsIdentity)claimsPrincipal.Identity;
        var claims = identity.Claims.ToList();
        var genericIdentity = new GenericIdentity(identity.Name);

        genericIdentity.AddClaims(claims);

        var genericPrincipal = new GenericPrincipal(genericIdentity, new string[] { identity.RoleClaimType });

        context.HttpContext.User = genericPrincipal;
    }
}

4. 将过滤器添加到 WeatherForecastController：使用 [JwtAuthorizationFilter] 属性将过滤器应用于 WeatherForecastController class。

[ApiController]
[Route("api/[controller]")]
[JwtAuthorizationFilter]
public class WeatherForecastController : ControllerBase
{
    private readonly IWeatherForecastService _weatherForecastService;
    
    public WeatherForecastController(IWeatherForecastService weatherForecastService)
    {
        _weatherForecastService = weatherForecastService;
    }
    
    [HttpGet]
    public IEnumerable<WeatherForecast> Get()
    {
        // check if the user is authorized
        if (!User.IsInRole("User"))
        {
            throw new UnauthorizedAccessException();
        }

        // return the weather forecast data
        return _weatherForecastService.GetWeatherForecasts();
    }
}

5.将JWT服务和认证服务添加到Dependency Injection容器中：在Startup.cs class中，将JwtService和JwtAuthenticationService类添加到Dependency Injection容器中，这样它们就可以作为依赖注入到其他类中。**

services.AddSingleton<JwtService>(new JwtService("your_secret_key"));
services.AddSingleton<JwtAuthenticationService>();

6. 将 JWT 过滤器添加到依赖注入容器：在Startup.cs class 中，将JwtAuthorizationFilter添加到依赖注入容器，以便它可以作为过滤器应用于控制器。**

services.AddSingleton<JwtAuthorizationFilter>();

这是更改后的最终Startup.cs ：

public class Startup
{
    public Startup(IConfiguration configuration)
    {
        Configuration = configuration;
    }

    public IConfiguration Configuration { get; }

    // This method gets called by the runtime. Use this method to add services to the container.
    public void ConfigureServices(IServiceCollection services)
    {
        services.AddSingleton<JwtService>(new JwtService("your_secret_key"));
        services.AddSingleton<JwtAuthenticationService>();
        services.AddSingleton<JwtAuthorizationFilter>();
        services.AddControllers();
        services.AddSwaggerGen(c =>
        {
            c.SwaggerDoc("v1", new OpenApiInfo { Title = "WeatherForecast", Version = "v1" });
        });
    }

    // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
    public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
    {
        if (env.IsDevelopment())
        {
            app.UseDeveloperExceptionPage();
            app.UseSwagger();
            app.UseSwaggerUI(c => c.SwaggerEndpoint("/swagger/v1/swagger.json", "WeatherForecast v1"));
        }

        app.UseHttpsRedirection();

        app.UseRouting();

        app.UseAuthorization();

        app.UseEndpoints(endpoints =>
        {
            endpoints.MapControllers();
        });
    }
}

错误：

There is no argument given that corresponds to the required parameter 'jwtService' of 'JwtAuthorizationFilter.JwtAuthorizationFilter(JwtService)'

错误出现在我在WeatherForecastController class 上添加[JwtAuthorizationFilter]属性的那一行：

[ApiController]
[Route("[controller]")]
[JwtAuthorizationFilter] // <-- Error occurs at this line
public class WeatherForecastController : ControllerBase { ...

我知道JwtAuthorizationFilter有一个接受JwtService类型参数的构造函数，但我不确定如何在 controller 或 Startup.cs 中提供它。

Answer 1

您不能像这样对属性使用构造函数 DI。 相反，在属性中获取您需要的服务。 例如：

public class JwtAuthorizationFilter : AuthorizationFilterAttribute
{
    public void OnAuthorization(AuthorizationFilterContext context)
    {
        var jwtService = context.HttpContext.RequestServices
            .GetRequiredService<JwtService>();

        //etc
    }
}