AddIdentity 与 AddIdentityCore

在ASP.NET Core中，可以添加各种服务进行识别：AddDefaultIdentity, AddIdentity and AddIdentityCore.

有什么区别AddIdentity and AddIdentityCore?

AddIdentityCore添加用户管理操作所需的服务，例如创建用户、散列密码等。以下是相关内容source https://github.com/aspnet/AspNetCore/blob/release/3.1/src/Identity/Extensions.Core/src/IdentityServiceCollectionExtensions.cs#L33-L56:

public static IdentityBuilder AddIdentityCore<TUser>(this IServiceCollection services, Action<IdentityOptions> setupAction)
    where TUser : class
{
    // Services identity depends on
    services.AddOptions().AddLogging();

    // Services used by identity
    services.TryAddScoped<IUserValidator<TUser>, UserValidator<TUser>>();
    services.TryAddScoped<IPasswordValidator<TUser>, PasswordValidator<TUser>>();
    services.TryAddScoped<IPasswordHasher<TUser>, PasswordHasher<TUser>>();
    services.TryAddScoped<ILookupNormalizer, UpperInvariantLookupNormalizer>();
    
    // No interface for the error describer so we can add errors without rev'ing the interface
    services.TryAddScoped<IdentityErrorDescriber>();
    services.TryAddScoped<IUserClaimsPrincipalFactory<TUser>, UserClaimsPrincipalFactory<TUser>>();
    services.TryAddScoped<UserManager<TUser>>();

    ...
}

本质上，这可以归结为注册一个实例UserManager<TUser>，但首先注册其所有依赖项。注册这些服务后，您可以检索UserManager<TUser>从 DI 并创建用户、设置密码、更改电子邮件等。

AddIdentity注册相同的服务AddIdentityCore，还有一些额外的内容：

• 针对应用程序本身、外部登录（例如 Facebook 和 Google）和 2FA 的基于 Cookie 的身份验证方案。
• The SignInManager，它实际上位于UserManager作为一种协调者。例如，PasswordSignInAsync uses UserManager要检索用户，请验证密码（如果已设置），然后负责 cookie 的创建。
• AddIdentity本身也需要一个TRole并注册支持角色所需的服务。

这是AddIdentity source https://github.com/aspnet/AspNetCore/blob/release/3.1/src/Identity/Core/src/IdentityServiceCollectionExtensions.cs#L38-L102为了完整性：

public static IdentityBuilder AddIdentity<TUser, TRole>(this IServiceCollection services, Action<IdentityOptions> setupAction)
    where TUser : class
    where TRole : class
{
    // Services used by identity
    services.AddAuthentication(options =>
    {
        options.DefaultAuthenticateScheme = IdentityConstants.ApplicationScheme;
        options.DefaultChallengeScheme = IdentityConstants.ApplicationScheme;
        options.DefaultSignInScheme = IdentityConstants.ExternalScheme;
    })
    .AddCookie(IdentityConstants.ApplicationScheme, o =>
    {
        o.LoginPath = new PathString("/Account/Login");
        o.Events = new CookieAuthenticationEvents
        {
            OnValidatePrincipal = SecurityStampValidator.ValidatePrincipalAsync
        };
    })
    .AddCookie(IdentityConstants.ExternalScheme, o =>
    {
        o.Cookie.Name = IdentityConstants.ExternalScheme;
        o.ExpireTimeSpan = TimeSpan.FromMinutes(5);
    })
    .AddCookie(IdentityConstants.TwoFactorRememberMeScheme, o =>
    {
        o.Cookie.Name = IdentityConstants.TwoFactorRememberMeScheme;
        o.Events = new CookieAuthenticationEvents
        {
            OnValidatePrincipal = SecurityStampValidator.ValidateAsync<ITwoFactorSecurityStampValidator>
        };
    })
    .AddCookie(IdentityConstants.TwoFactorUserIdScheme, o =>
    {
        o.Cookie.Name = IdentityConstants.TwoFactorUserIdScheme;
        o.ExpireTimeSpan = TimeSpan.FromMinutes(5);
    });

    // Hosting doesn't add IHttpContextAccessor by default
    services.AddHttpContextAccessor();
    
    // Identity services
    services.TryAddScoped<IUserValidator<TUser>, UserValidator<TUser>>();
    services.TryAddScoped<IPasswordValidator<TUser>, PasswordValidator<TUser>>();
    services.TryAddScoped<IPasswordHasher<TUser>, PasswordHasher<TUser>>();
    services.TryAddScoped<ILookupNormalizer, UpperInvariantLookupNormalizer>();
    services.TryAddScoped<IRoleValidator<TRole>, RoleValidator<TRole>>();
    // No interface for the error describer so we can add errors without rev'ing the interface
    services.TryAddScoped<IdentityErrorDescriber>();
    services.TryAddScoped<ISecurityStampValidator, SecurityStampValidator<TUser>>();
    services.TryAddScoped<ITwoFactorSecurityStampValidator, TwoFactorSecurityStampValidator<TUser>>();
    services.TryAddScoped<IUserClaimsPrincipalFactory<TUser>, UserClaimsPrincipalFactory<TUser, TRole>>();
    services.TryAddScoped<UserManager<TUser>>();
    services.TryAddScoped<SignInManager<TUser>>();
    services.TryAddScoped<RoleManager<TRole>>();

    ...
}