目录

• identityserver4源码解析_1_项目结构
• identityserver4源码解析_2_元数据接口
• identityserver4源码解析_3_认证接口
• identityserver4源码解析_4_令牌发放接口
• identityserver4源码解析_5_查询用户信息接口
• identityserver4源码解析_6_结束会话接口
• identityserver4源码解析_7_查询令牌信息接口
• identityserver4源码解析_8_撤销令牌接口

简介

Security源码解析系列介绍了微软提供的各种认证架构，其中OAuth2.0，OpenIdConnect属于远程认证架构，所谓远程认证，是指token的颁发是由另外的站点实现的。

IdentityServer4是基于OpenIdConnect协议的认证中心框架，能够帮助我们搭建中心化的认证服务。

可以将OpenIdConnect协议立即理解成需求文档，idsv4基于需求提供了一系列的api。

对于idsv还不太了解的可以看下面的资料，本系列主要学习梳理idsv的源码，结合协议加深理解。

晓晨姐姐系列文章

https://www.cnblogs.com/stulzq/p/8119928.html

官方文档

https://identityserver4.readthedocs.io/en/latest/

项目结构

项目地址如下

https://github.com/IdentityServer/IdentityServer4

克隆到本地，项目结构如图

核心项目是IdentityServer4，其余的都是与微软框架集成、以及处理持久化的项目。
项目结构如图。Endpoints文件夹就是接口文件，我们先看下依赖注入、中间件的代码，然后看下每个接口。

依赖注入

public static IIdentityServerBuilder AddIdentityServer(this IServiceCollection services)
{
    var builder = services.AddIdentityServerBuilder();

    builder
        .AddRequiredPlatformServices()
        .AddCookieAuthentication()
        .AddCoreServices()
        .AddDefaultEndpoints()
        .AddPluggableServices()
        .AddValidators()
        .AddResponseGenerators()
        .AddDefaultSecretParsers()
        .AddDefaultSecretValidators();

    // provide default in-memory implementation, not suitable for most production scenarios
    builder.AddInMemoryPersistedGrants();

    return builder;
}

• AddRequiredPlatformServices - 注入平台服务
  • IHttpContextAccessor：HttpContext访问器
    
  • IdentityServerOptions：配置类

   public static IIdentityServerBuilder AddRequiredPlatformServices(this IIdentityServerBuilder builder)
  {
    builder.Services.TryAddSingleton<IHttpContextAccessor, HttpContextAccessor>();            
    builder.Services.AddOptions();
    builder.Services.AddSingleton(
        resolver => resolver.GetRequiredService<IOptions<IdentityServerOptions>>().Value);
    builder.Services.AddHttpClient();
  
    return builder;
  }

• AddCookieAuthentication - 注入cookie服务
  • 注入名称为idsrv的cookie认证架构
  • 注入IAuthenticationService的实现IdentityServerAuthenticationService
  • 注入IAuthenticationHandlerProvider的实现FederatedSignoutAuthenticationHandlerProvider

  public static IIdentityServerBuilder AddCookieAuthentication(this IIdentityServerBuilder builder)
  {
    builder.Services.AddAuthentication(IdentityServerConstants.DefaultCookieAuthenticationScheme)
        .AddCookie(IdentityServerConstants.DefaultCookieAuthenticationScheme)
        .AddCookie(IdentityServerConstants.ExternalCookieAuthenticationScheme);
  
    builder.Services.AddSingleton<IConfigureOptions<CookieAuthenticationOptions>, ConfigureInternalCookieOptions>();
    builder.Services.AddSingleton<IPostConfigureOptions<CookieAuthenticationOptions>, PostConfigureInternalCookieOptions>();
    builder.Services.AddTransientDecorator<IAuthenticationService, IdentityServerAuthenticationService>();
    builder.Services.AddTransientDecorator<IAuthenticationHandlerProvider, FederatedSignoutAuthenticationHandlerProvider>();
  
    return builder;
  }

• AddCoreServices - 注入核心服务

/// <summary>
/// Adds the core services.
/// </summary>
/// <param name="builder">The builder.</param>
/// <returns></returns>
public static IIdentityServerBuilder AddCoreServices(this IIdentityServerBuilder builder)
{
    builder.Services.AddTransient<SecretParser>();
    builder.Services.AddTransient<SecretValidator>();
    builder.Services.AddTransient<ScopeValidator>();
    builder.Services.AddTransient<ExtensionGrantValidator>();
    builder.Services.AddTransient<BearerTokenUsageValidator>();
    builder.Services.AddTransient<JwtRequestValidator>();

    // todo: remove in 3.0
#pragma warning disable CS0618 // Type or member is obsolete
    builder.Services.AddTransient<BackChannelHttpClient>();
#pragma warning restore CS0618 // Type or member is obsolete

    builder.Services.AddTransient<ReturnUrlParser>();
    builder.Services.AddTransient<IdentityServerTools>();

    builder.Services.AddTransient<IReturnUrlParser, OidcReturnUrlParser>();
    builder.Services.AddScoped<IUserSession, DefaultUserSession>();
    builder.Services.AddTransient(typeof(MessageCookie<>));

    builder.Services.AddCors();
    builder.Services.AddTransientDecorator<ICorsPolicyProvider, CorsPolicyProvider>();

    return builder;
}

• AddDefaultEndpoints - 注入接口
  • AuthorizeCallbackEndpoint：认证回调接口
  • AuthorizeEndpoint：认证接口
  • CheckSessionEndpoint：检查会话接口
  • DeviceAuthorizationEndpoint：设备认证接口
  • DiscoveryEndpoint：元数据键接口
  • DiscoveryEndpoint：元数据接口
  • EndSessionCallbackEndpoint：结束会话回调接口
  • EndSessionEndpoint：结束会话接口
  • IntrospectionEndpoint：查询令牌信息接口
  • TokenRevocationEndpoint：撤销令牌接口
  • TokenEndpoint：发放令牌接口
  • UserInfoEndpoint：查询用户信息接口

   public static IIdentityServerBuilder AddDefaultEndpoints(this IIdentityServerBuilder builder)
  {
    builder.Services.AddTransient<IEndpointRouter, EndpointRouter>();
  
    builder.AddEndpoint<AuthorizeCallbackEndpoint>(EndpointNames.Authorize, ProtocolRoutePaths.AuthorizeCallback.EnsureLeadingSlash());
    builder.AddEndpoint<AuthorizeEndpoint>(EndpointNames.Authorize, ProtocolRoutePaths.Authorize.EnsureLeadingSlash());
    builder.AddEndpoint<CheckSessionEndpoint>(EndpointNames.CheckSession, ProtocolRoutePaths.CheckSession.EnsureLeadingSlash());
    builder.AddEndpoint<DeviceAuthorizationEndpoint>(EndpointNames.DeviceAuthorization, ProtocolRoutePaths.DeviceAuthorization.EnsureLeadingSlash());
    builder.AddEndpoint<DiscoveryKeyEndpoint>(EndpointNames.Discovery, ProtocolRoutePaths.DiscoveryWebKeys.EnsureLeadingSlash());
    builder.AddEndpoint<DiscoveryEndpoint>(EndpointNames.Discovery, ProtocolRoutePaths.DiscoveryConfiguration.EnsureLeadingSlash());
    builder.AddEndpoint<EndSessionCallbackEndpoint>(EndpointNames.EndSession, ProtocolRoutePaths.EndSessionCallback.EnsureLeadingSlash());
    builder.AddEndpoint<EndSessionEndpoint>(EndpointNames.EndSession, ProtocolRoutePaths.EndSession.EnsureLeadingSlash());
    builder.AddEndpoint<IntrospectionEndpoint>(EndpointNames.Introspection, ProtocolRoutePaths.Introspection.EnsureLeadingSlash());
    builder.AddEndpoint<TokenRevocationEndpoint>(EndpointNames.Revocation, ProtocolRoutePaths.Revocation.EnsureLeadingSlash());
    builder.AddEndpoint<TokenEndpoint>(EndpointNames.Token, ProtocolRoutePaths.Token.EnsureLeadingSlash());
    builder.AddEndpoint<UserInfoEndpoint>(EndpointNames.UserInfo, ProtocolRoutePaths.UserInfo.EnsureLeadingSlash());
  
    return builder;
  }

• AddPluggableServices - 注入可插拔服务

public static IIdentityServerBuilder AddPluggableServices(this IIdentityServerBuilder builder)
{
    builder.Services.TryAddTransient<IPersistedGrantService, DefaultPersistedGrantService>();
    builder.Services.TryAddTransient<IKeyMaterialService, DefaultKeyMaterialService>();
    builder.Services.TryAddTransient<ITokenService, DefaultTokenService>();
    builder.Services.TryAddTransient<ITokenCreationService, DefaultTokenCreationService>();
    builder.Services.TryAddTransient<IClaimsService, DefaultClaimsService>();
    builder.Services.TryAddTransient<IRefreshTokenService, DefaultRefreshTokenService>();
    builder.Services.TryAddTransient<IDeviceFlowCodeService, DefaultDeviceFlowCodeService>();
    builder.Services.TryAddTransient<IConsentService, DefaultConsentService>();
    builder.Services.TryAddTransient<ICorsPolicyService, DefaultCorsPolicyService>();
    builder.Services.TryAddTransient<IProfileService, DefaultProfileService>();
    builder.Services.TryAddTransient<IConsentMessageStore, ConsentMessageStore>();
    builder.Services.TryAddTransient<IMessageStore<LogoutMessage>, ProtectedDataMessageStore<LogoutMessage>>();
    builder.Services.TryAddTransient<IMessageStore<EndSession>, ProtectedDataMessageStore<EndSession>>();
    builder.Services.TryAddTransient<IMessageStore<ErrorMessage>, ProtectedDataMessageStore<ErrorMessage>>();
    builder.Services.TryAddTransient<IIdentityServerInteractionService, DefaultIdentityServerInteractionService>();
    builder.Services.TryAddTransient<IDeviceFlowInteractionService, DefaultDeviceFlowInteractionService>();
    builder.Services.TryAddTransient<IAuthorizationCodeStore, DefaultAuthorizationCodeStore>();
    builder.Services.TryAddTransient<IRefreshTokenStore, DefaultRefreshTokenStore>();
    builder.Services.TryAddTransient<IReferenceTokenStore, DefaultReferenceTokenStore>();
    builder.Services.TryAddTransient<IUserConsentStore, DefaultUserConsentStore>();
    builder.Services.TryAddTransient<IHandleGenerationService, DefaultHandleGenerationService>();
    builder.Services.TryAddTransient<IPersistentGrantSerializer, PersistentGrantSerializer>();
    builder.Services.TryAddTransient<IEventService, DefaultEventService>();
    builder.Services.TryAddTransient<IEventSink, DefaultEventSink>();
    builder.Services.TryAddTransient<IUserCodeService, DefaultUserCodeService>();
    builder.Services.TryAddTransient<IUserCodeGenerator, NumericUserCodeGenerator>();
    builder.Services.TryAddTransient<IBackChannelLogoutService, DefaultBackChannelLogoutService>();

    builder.AddJwtRequestUriHttpClient();
    builder.AddBackChannelLogoutHttpClient();
    //builder.Services.AddHttpClient<BackChannelLogoutHttpClient>();
    //builder.Services.AddHttpClient<JwtRequestUriHttpClient>();

    builder.Services.AddTransient<IClientSecretValidator, ClientSecretValidator>();
    builder.Services.AddTransient<IApiSecretValidator, ApiSecretValidator>();

    builder.Services.TryAddTransient<IDeviceFlowThrottlingService, DistributedDeviceFlowThrottlingService>();
    builder.Services.AddDistributedMemoryCache();

    return builder;
}

• AddValidators - 注入校验类

public static IIdentityServerBuilder AddValidators(this IIdentityServerBuilder builder)
{
    // core
    builder.Services.TryAddTransient<IEndSessionRequestValidator, EndSessionRequestValidator>();
    builder.Services.TryAddTransient<ITokenRevocationRequestValidator, TokenRevocationRequestValidator>();
    builder.Services.TryAddTransient<IAuthorizeRequestValidator, AuthorizeRequestValidator>();
    builder.Services.TryAddTransient<ITokenRequestValidator, TokenRequestValidator>();
    builder.Services.TryAddTransient<IRedirectUriValidator, StrictRedirectUriValidator>();
    builder.Services.TryAddTransient<ITokenValidator, TokenValidator>();
    builder.Services.TryAddTransient<IIntrospectionRequestValidator, IntrospectionRequestValidator>();
    builder.Services.TryAddTransient<IResourceOwnerPasswordValidator, NotSupportedResourceOwnerPasswordValidator>();
    builder.Services.TryAddTransient<ICustomTokenRequestValidator, DefaultCustomTokenRequestValidator>();
    builder.Services.TryAddTransient<IUserInfoRequestValidator, UserInfoRequestValidator>();
    builder.Services.TryAddTransient<IClientConfigurationValidator, DefaultClientConfigurationValidator>();
    builder.Services.TryAddTransient<IDeviceAuthorizationRequestValidator, DeviceAuthorizationRequestValidator>();
    builder.Services.TryAddTransient<IDeviceCodeValidator, DeviceCodeValidator>();

    // optional
    builder.Services.TryAddTransient<ICustomTokenValidator, DefaultCustomTokenValidator>();
    builder.Services.TryAddTransient<ICustomAuthorizeRequestValidator, DefaultCustomAuthorizeRequestValidator>();
    
    return builder;
}

• AddResponseGenerators - 注入响应生成类

public static IIdentityServerBuilder AddResponseGenerators(this IIdentityServerBuilder builder)
{
    builder.Services.TryAddTransient<ITokenResponseGenerator, TokenResponseGenerator>();
    builder.Services.TryAddTransient<IUserInfoResponseGenerator, UserInfoResponseGenerator>();
    builder.Services.TryAddTransient<IIntrospectionResponseGenerator, IntrospectionResponseGenerator>();
    builder.Services.TryAddTransient<IAuthorizeInteractionResponseGenerator, AuthorizeInteractionResponseGenerator>();
    builder.Services.TryAddTransient<IAuthorizeResponseGenerator, AuthorizeResponseGenerator>();
    builder.Services.TryAddTransient<IDiscoveryResponseGenerator, DiscoveryResponseGenerator>();
    builder.Services.TryAddTransient<ITokenRevocationResponseGenerator, TokenRevocationResponseGenerator>();
    builder.Services.TryAddTransient<IDeviceAuthorizationResponseGenerator, DeviceAuthorizationResponseGenerator>();

    return builder;
}

• AddDefaultSecretParsers & AddDefaultSecretValidators

/// <summary>
/// Adds the default secret parsers.
/// </summary>
/// <param name="builder">The builder.</param>
/// <returns></returns>
public static IIdentityServerBuilder AddDefaultSecretParsers(this IIdentityServerBuilder builder)
{
    builder.Services.AddTransient<ISecretParser, BasicAuthenticationSecretParser>();
    builder.Services.AddTransient<ISecretParser, PostBodySecretParser>();

    return builder;
}

/// <summary>
/// Adds the default secret validators.
/// </summary>
/// <param name="builder">The builder.</param>
/// <returns></returns>
public static IIdentityServerBuilder AddDefaultSecretValidators(this IIdentityServerBuilder builder)
{
    builder.Services.AddTransient<ISecretValidator, HashedSharedSecretValidator>();

    return builder;
}

IdentityServerOptions - 配置类

 /// <summary>
/// The IdentityServerOptions class is the top level container for all configuration settings of IdentityServer.
/// </summary>
public class IdentityServerOptions
{
    /// <summary>
    /// Gets or sets the unique name of this server instance, e.g. https://myissuer.com.
    /// If not set, the issuer name is inferred from the request
    /// </summary>
    /// <value>
    /// Unique name of this server instance, e.g. https://myissuer.com
    /// </value>
    public string IssuerUri { get; set; }

    /// <summary>
    /// Gets or sets the origin of this server instance, e.g. https://myorigin.com.
    /// If not set, the origin name is inferred from the request
    /// Note: Do not set a URL or include a path.
    /// </summary>
    /// <value>
    /// Origin of this server instance, e.g. https://myorigin.com
    /// </value>
    public string PublicOrigin { get; set; }

    /// <summary>
    /// Gets or sets the value for the JWT typ header for access tokens.
    /// </summary>
    /// <value>
    /// The JWT typ value.
    /// </value>
    public string AccessTokenJwtType { get; set; } = "at+jwt";

    /// <summary>
    /// Emits an aud claim with the format issuer/resources. That's needed for some older access token validation plumbing. Defaults to false.
    /// </summary>
    public bool EmitLegacyResourceAudienceClaim { get; set; } = false;

    /// <summary>
    /// Gets or sets the endpoint configuration.
    /// </summary>
    /// <value>
    /// The endpoints configuration.
    /// </value>
    public EndpointsOptions Endpoints { get; set; } = new EndpointsOptions();

    /// <summary>
    /// Gets or sets the discovery endpoint configuration.
    /// </summary>
    /// <value>
    /// The discovery endpoint configuration.
    /// </value>
    public DiscoveryOptions Discovery { get; set; } = new DiscoveryOptions();

    /// <summary>
    /// Gets or sets the authentication options.
    /// </summary>
    /// <value>
    /// The authentication options.
    /// </value>
    public AuthenticationOptions Authentication { get; set; } = new AuthenticationOptions();

    /// <summary>
    /// Gets or sets the events options.
    /// </summary>
    /// <value>
    /// The events options.
    /// </value>
    public EventsOptions Events { get; set; } = new EventsOptions();

    /// <summary>
    /// Gets or sets the max input length restrictions.
    /// </summary>
    /// <value>
    /// The length restrictions.
    /// </value>
    public InputLengthRestrictions InputLengthRestrictions { get; set; } = new InputLengthRestrictions();

    /// <summary>
    /// Gets or sets the options for the user interaction.
    /// </summary>
    /// <value>
    /// The user interaction options.
    /// </value>
    public UserInteractionOptions UserInteraction { get; set; } = new UserInteractionOptions();

    /// <summary>
    /// Gets or sets the caching options.
    /// </summary>
    /// <value>
    /// The caching options.
    /// </value>
    public CachingOptions Caching { get; set; } = new CachingOptions();

    /// <summary>
    /// Gets or sets the cors options.
    /// </summary>
    /// <value>
    /// The cors options.
    /// </value>
    public CorsOptions Cors { get; set; } = new CorsOptions();

    /// <summary>
    /// Gets or sets the Content Security Policy options.
    /// </summary>
    public CspOptions Csp { get; set; } = new CspOptions();

    /// <summary>
    /// Gets or sets the validation options.
    /// </summary>
    public ValidationOptions Validation { get; set; } = new ValidationOptions();

    /// <summary>
    /// Gets or sets the device flow options.
    /// </summary>
    public DeviceFlowOptions DeviceFlow { get; set; } = new DeviceFlowOptions();

    /// <summary>
    /// Gets or sets the mutual TLS options.
    /// </summary>
    public MutualTlsOptions MutualTls { get; set; } = new MutualTlsOptions();
}

UserIdentityServer - 中间件逻辑

• 执行校验
• BaseUrlMiddleware中间件：设置BaseUrl
• 配置CORS跨域：CorsPolicyProvider根据client信息生成动态策略
• IdentityServerMiddlewareOptions默认调用了UseAuthentication，所以如果使用IdentityServer不用重复注册Authentication中间件
• 使用MutualTlsTokenEndpointMiddleware中间件：要求客户端、服务端都使用https，默认不开启
• 使用IdentityServerMiddleware中间件：IEndpointRouter根据请求寻找匹配的IEndpointHandler，如果找到的话则由EndPointHandler处理请求。

public static IApplicationBuilder UseIdentityServer(this IApplicationBuilder app, IdentityServerMiddlewareOptions options = null)
{
    app.Validate();

    app.UseMiddleware<BaseUrlMiddleware>();

    app.ConfigureCors();

    // it seems ok if we have UseAuthentication more than once in the pipeline --
    // this will just re-run the various callback handlers and the default authN 
    // handler, which just re-assigns the user on the context. claims transformation
    // will run twice, since that's not cached (whereas the authN handler result is)
    // related: https://github.com/aspnet/Security/issues/1399
    if (options == null) options = new IdentityServerMiddlewareOptions();
    options.AuthenticationMiddleware(app);

    app.UseMiddleware<MutualTlsTokenEndpointMiddleware>();
    app.UseMiddleware<IdentityServerMiddleware>();

    return app;
}

结语

idsv的代码量还是比较大的，注入了大量的类。但是代码风格比较规范，脉络还是很清晰的。