customizing login credentials for a single guard in laravel multi-authentication - laravel

Question

I have multi-authentication set up in my laravel app. I set up different guards and providers for admin, doctor and patient. I've also set up the redirects for the various guards in my config\auth.php.
The only issue i'm having right now is, I want doctors to login with a unique number called MDCN which is saved to the database table instead of email. Please how do i customize the login for the doctors?
Ps: I've also set up the models for each, and i use laravel default auth.
my guard:
'guards' => [
'web' => [
'driver' => 'session',
'provider' => 'users',
],
'api' => [
'driver' => 'token',
'provider' => 'users',
],
'admin' => [
'driver' => 'session',
'provider' => 'admins',
],
'admin-api' => [
'driver' => 'token',
'provider' => 'admins',
],
'doctor' => [
'driver' => 'session',
'provider' => 'doctors',
],
'doctor-api' => [
'driver' => 'token',
'provider' => 'doctors',
],
],
and provider:
'providers' => [
'users' => [
'driver' => 'eloquent',
'model' => App\Models\User::class,
],
'admins' => [
'driver' => 'eloquent',
'model' => App\Models\Admin::class,
],
'doctors' => [
'driver' => 'eloquent',
'model' => App\Models\Doctor::class,
],
],

Answer 1

In the App\Http\Controllers\Auth\LoginController you can override a method which returns by what fields the authentication should be checked and there you can pass the MDCN if you're logging a doctor:
protected function credentials(Request $request)
{
return $request->only('MDCN', 'password');
}

Answer 2

i finally solved this, thank to Alex Curtis.
In order to do this, you need to customize each model to tell it what you want to use to login.
So on any model that you want to log in with a username instead of an email you need to add this block of code to the model:
public function username()
{
return 'username';
}
And just make sure that the value you return (username in this example) matches the column name in that model's table that has the identifier you are looking to use.
Obviously you would also want to make sure you have a column in the DB to hold this data, you want it to be mass-assignable (by customizing the $fillable array in the model) and you also want the column to be indexed and unique.
To get this you want to create the column in a migration that looks like this:
$table->string('username')->unique();
This will make a unique index for that column.
The default is email, so if you are using email then you don't need to worry about this, but any model using something other than email will need this change made to that user type's model.