AspNetCore3.1_Secutiry源码解析_2_Authentication_核心对象

文章目录

依赖注入

框架提供了三个依赖注入重载方法。

//注入认证服务services.AddAuthentication();//注入认证服务并制定默认架构名services.AddAuthentication("Cookies");//注入认证服务并设置配置项services.AddAuthentication(config => {});

看看注入代码

public static AuthenticationBuilder AddAuthentication(this IServiceCollection services)    {        if (services == null)        {            throw new ArgumentNullException(nameof(services));        }        services.AddAuthenticationCore();        services.AddDataProtection();        services.AddWebEncoders();        services.TryAddSingleton<ISystemClock, SystemClock>();        return new AuthenticationBuilder(services);    }

AddAuthenticationCore注入了认证服务的核心对象。这个方法在Authentication.Core项目，这个项目定义了认证服务的核心对象，在Authentication.Abstractions项目中定义了核心接口。

AddAuthenticationCore方法注入了IAuthenticationService，IClaimsTransformation，IAuthenticationHandlerProvider，IAuthenticationSchemeProvider

public static IServiceCollection AddAuthenticationCore(this IServiceCollection services){    if (services == null)    {        throw new ArgumentNullException(nameof(services));    }    services.TryAddScoped<IAuthenticationService, AuthenticationService>();    services.TryAddSingleton<IClaimsTransformation, NoopClaimsTransformation>(); // Can be replaced with scoped ones that use DbContext    services.TryAddScoped<IAuthenticationHandlerProvider, AuthenticationHandlerProvider>();    services.TryAddSingleton<IAuthenticationSchemeProvider, AuthenticationSchemeProvider>();    return services;}

IAuthenticationService

认证服务，定义了五个方法

  • AuthenticateAsync: 认证
  • ChallengeAsync：挑战，校验认证
  • ForbidAsync：禁止认证
  • SignInAsync：登入
  • SignOutAsync：登出
classDiagram class IAuthenticationService{ +AuthenticateAsync(HttpContext context, string scheme) +ChallengeAsync(HttpContext context, string scheme, AuthenticationProperties properties) +ForbidAsync(HttpContext context, string scheme, AuthenticationProperties properties) +SignInAsync(HttpContext context, string scheme, ClaimsPrincipal principal, AuthenticationProperties properties) +SignOutAsync(HttpContext context, string scheme, AuthenticationProperties properties) }

通过AuthenticateAsync方法源代码可以看到，AuthenticateService只是做了控制器的角色，校验schema，根据schema获取handler，主要的认证逻辑是由handler处理。其他的方法基本也是这样的逻辑。

 public virtual async Task<AuthenticateResult> AuthenticateAsync(HttpContext context, string scheme){    if (scheme == null)    {        var defaultScheme = await Schemes.GetDefaultAuthenticateSchemeAsync();        scheme = defaultScheme?.Name;        if (scheme == null)        {            throw new InvalidOperationException($"No authenticationScheme was specified, and there was no DefaultAuthenticateScheme found. The default schemes can be set using either AddAuthentication(string defaultScheme) or AddAuthentication(Action<AuthenticationOptions> configureOptions).");        }    }    var handler = await Handlers.GetHandlerAsync(context, scheme);    if (handler == null)    {        throw await CreateMissingHandlerException(scheme);    }    var result = await handler.AuthenticateAsync();    if (result != null && result.Succeeded)    {        var transformed = await Transform.TransformAsync(result.Principal);        return AuthenticateResult.Success(new AuthenticationTicket(transformed, result.Properties, result.Ticket.AuthenticationScheme));    }    return result;}

IClaimsTransformation

classDiagram class IClaimsTransformation{ +TransformAsync(ClaimsPrincipal principal) }

该接口只有一个方法，用于转换Claims。默认注入的NoopClaimsTransformation，不会做任何操作。如果需要对Claims做一些处理，实现IClaimsTransformation并覆盖注入就可以了。

public class NoopClaimsTransformation : IClaimsTransformation{    /// <summary>    /// Returns the principal unchanged.    /// </summary>    /// <param name="principal">The user.</param>    /// <returns>The principal unchanged.</returns>    public virtual Task<ClaimsPrincipal> TransformAsync(ClaimsPrincipal principal)    {        return Task.FromResult(principal);    }}

IAuthenticationHandlerProvider

classDiagram class IAuthenticationHandlerProvider{ +GetHandlerAsync(HttpContext context, string authenticationScheme) }

上面提到过handler处理了主要的认证业务逻辑，这个接口可以根据schema获取handler。

IAuthenticationSchemeProvider

classDiagram class IAuthenticationSchemeProvider{ +GetAllSchemesAsync() +GetSchemeAsync(string name) +GetDefaultAuthenticateSchemeAsync() +GetDefaultChallengeSchemeAsync() +GetDefaultForbidSchemeAsync() +GetDefaultSignInSchemeAsync() +GetDefaultSignOutSchemeAsync() +AddScheme(AuthenticationScheme scheme) +RemoveScheme(string name) +GetRequestHandlerSchemesAsync() }

该接口主要定义了一些schema的操作方法。

AuthenticationScheme主要有三个属性，通过HandlerType与handler建立了关联。

classDiagram class AuthenticationScheme{ Name DisplayName HandlerType }

认证流程

graph TD A(AuthenticationOptions定义五个认证动作的Schema) A --> B1(Authenticate) A --> B2(Challenge) A --> B3(Forbid) A --> B4(SignIn) A --> B5(SingOut) C(IAuthenticationSchemeProvider获取Schema) B1 --> C B2 --> C B3 --> C B4 --> C B5 --> C C --> D(IAuthenticationHandlerProvider获取Schema对应的Handler) D --> E(处理请求)

其他

除了核心对象，还注入了用于数据保护和解码的辅助对象

services.AddDataProtection();services.AddWebEncoders();

Authentication中间件

中间件会优先在容器中找IAuthenticationRequestHandler的实现，如果handler不为空的话，则执行handler的HandleRequestAsync方法。IAuthenticationRequestHandler通常在远程认证（如：OAuth, OIDC等）中使用。

如果没有IAuthenticationRequestHandler的实现，则会找默认schema，执行默认schema对应handler的AuthenticationAsync方法，认证成功后，给HttpContext的User对象赋值。

public async Task Invoke(HttpContext context)    {        context.Features.Set<IAuthenticationFeature>(new AuthenticationFeature        {            OriginalPath = context.Request.Path,            OriginalPathBase = context.Request.PathBase        });        // Give any IAuthenticationRequestHandler schemes a chance to handle the request        var handlers = context.RequestServices.GetRequiredService<IAuthenticationHandlerProvider>();        foreach (var scheme in await Schemes.GetRequestHandlerSchemesAsync())        {            var handler = await handlers.GetHandlerAsync(context, scheme.Name) as IAuthenticationRequestHandler;            if (handler != null && await handler.HandleRequestAsync())            {                return;            }        }        var defaultAuthenticate = await Schemes.GetDefaultAuthenticateSchemeAsync();        if (defaultAuthenticate != null)        {            var result = await context.AuthenticateAsync(defaultAuthenticate.Name);            if (result?.Principal != null)            {                context.User = result.Principal;            }        }        await _next(context);    }
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