Using models relationships in Laravel Validation Rule 'Exists' - php

Question

Db schema
users
-id
-name
-email
...
roles
-id
-name
User may have multiple roles and vice-versa (i already defined
relationships in models)
pivot table
role_user
-id
-user_id
-role_id
Validation rule trying to make: user_id must exist in users table and has role id = 4
//...
'user_id' => ['nullable', Rule::exists('users')->where(
function ($query) {
$query->whereHas('roles',
function ($q) {
$q->where('id', 4);
}
);
}
)],
//...
Error message : "SQLSTATE[42S22]: Column not found: 1054 Unknown
column 'has' in 'where clause' (SQL: select count(*) as aggregate from
users where user_id = 0 and (has = roles))"

Answer 1

I would use this. This will solve your problem, but i don't know either is the best way or not.
use Validator; // on the top
$validator = Validator::make($request->all(), [
'user_id' => 'nullable|numeric|exists:users,id',
]);
if ($validator->fails()) {
return response()->json($validator->errors(), 422);
}
$user = User::find($request->user_id);
if(!$user || !$user->roles->first() || $user->roles->first()->id != 4) {
return response()->json(['user_id'=>['You dont have permission.']], 422);
}
Another way you can try
'user_id' => [
'nullable',
'numeric',
'exists:users,id',
function ($attribute, $value, $fail) {
$editorsIDs = User::whereHas('roles', function ($q) {
$q->where('id', 4);
})->pluck('id');
if(! $editorsIDs->contains($value)) {
$fail('You dont have permission.');
}}
]

Answer 2

I resolve it using
$usersWhereHasEditorRole = User::whereHas('roles', function ($q) {
$q->where('id', 4);
})->pluck('id')->unique('id')->toArray();
$validator = Validator::make($request->all(), [
'name' => 'required|alpha', // commun
'email' => 'required|email|unique:users', // commun
'password' => 'required|min:8|regex:/[a-z]/|regex:/[A-Z]/|regex:/[0-9]/|regex:/[#$!%*#?&]/', // commun
'c_password' => 'required|same:password', // commun
//...
'user_id' => ['nullable', Rule::in($usersWhereHasEditorRole)],
//...
]);
if ($validator->fails()) {
return $this->sendError('Validation Error.', $validator->errors(), 400);
}
dd('passes');