Abp: Authentication Extensibility system to check username & password from an external source

[hikalkan]

ASP.NET Boilerplate has a good feature, named "External Authentication": https://aspnetboilerplate.com/Pages/Documents/Zero/User-Management#external-authentication

It makes possible to check username & password from any source (a database, a REST service, LDAP.... etc.). This is a good system which allows to easily extend the authentication mechanism.

I will implement a similar system for the ABP Framework, in the Identity module.

[hikalkan]

Done. This will be (eventually) documented. But, if you want to use it today;

1. Create a class inherits from the ExternalLoginProviderBase (defined in the Volo.Abp.Identity.AspNetCore package). Example:

````csharp
using System;
using System.Threading.Tasks;
using Volo.Abp.DependencyInjection;
using Volo.Abp.Guids;
using Volo.Abp.MultiTenancy;

namespace Volo.Abp.Identity.AspNetCore
{
public class FakeExternalLoginProvider : ExternalLoginProviderBase, ITransientDependency
{
public const string Name = "Fake";

    public FakeExternalLoginProvider(
        IGuidGenerator guidGenerator,
        ICurrentTenant currentTenant,
        IdentityUserManager userManager,
        IIdentityUserRepository identityUserRepository)
        : base(
            guidGenerator,
            currentTenant,
            userManager,
            identityUserRepository)
    {

    }

    public override Task<bool> TryAuthenticateAsync(string userName, string plainPassword)
    {
        return Task.FromResult(
            userName == "ext_user" && plainPassword == "abc"
        );
    }

    protected override Task<ExternalLoginUserInfo> GetUserInfoAsync(string userName)
    {
        if (userName != "ext_user")
        {
            throw new ArgumentException();
        }

        return Task.FromResult(
            new ExternalLoginUserInfo("[email protected]")
            {
                Name = "Test Name", //optional, if the provider knows it
                Surname = "Test Surname", //optional, if the provider knows it
                EmailConfirmed = true, //optional, if the provider knows it
                TwoFactorEnabled = false, //optional, if the provider knows it
                PhoneNumber = "123", //optional, if the provider knows it
                PhoneNumberConfirmed = false, //optional, if the provider knows it
                ProviderKey = "123" //The id of the user on the provider side
            }
        );
    }
}

}
````

TryAuthenticateAsync should check user & pass and GetUserInfoAsync should provide user details. GetUserInfoAsync is called on create (when the user first logins) and update (subsequent logins).

1. Register to the AbpIdentityAspNetCoreOptions:

csharp Configure<AbpIdentityAspNetCoreOptions>(options => { options.ExternalLoginProviders.Add<FakeExternalLoginProvider>(FakeExternalLoginProvider.Name); });

You can register more than one provider.

Additional notes

• This feature comes with a new IsExternal field to the IdentityUser which is set to true if the user was created on an external authentication process.

[jortygu]

@hikalkan it should be Register to the AbpIdentityOptions，not AbpIdentityAspNetCoreOptions