AddIdentityCore
adds the services that are necessary for user-management actions, such as creating users, hashing passwords, etc. Here’s the relevant source:
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>>();
...
}
Essentially, this boils down to registering an instance of UserManager<TUser>
, but first registers all of its dependencies. With these services registered, you can retrieve an instance of UserManager<TUser>
from DI and create users, set passwords, change emails, etc.
AddIdentity
registers the same services as AddIdentityCore
, with a few extras:
- Cookie-based authentication schemes for the application itself, external sign-in (e.g. Facebook and Google), and 2FA.
- The
SignInManager
, which effectively sits on top of theUserManager
as a sort of orchestrator. For example,PasswordSignInAsync
usesUserManager
to retrieve a user, verify the password (if set) and then takes care of cookie creation. AddIdentity
itself also takes aTRole
and registers the services that are necessary for supporting Roles.
Here’s the AddIdentity
source for completeness:
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>>();
...
}