Laravel form validation: same as field a or b - php

Question

I have 3 fields: player1, player2 and winner. I want to validate that winner is equal to either player1 or player 2.
I tried looking for a way to add an 'or' clause to the validation but couldn't find anything, only workarounds for different problems.

Answer 1

You can use a custom validation rule to do this. There's nothing built in that allows comparison to one of many other fields. The closest is the same check, but it only checks against one other field.
(I've added dd() to dump data, you can remove them)
The $values will be what comes from your input.
The $validationRules can be adjusted for your needs.
Validator::extend('equals_one_of', function($attribute, $value, $parameters, \Illuminate\Validation\Validator $validator) {
$fields = $validator->getData(); // all posted values
foreach($parameters as $param) { // this is each of the comma separated fields in the validationRules array
if ($value == $fields[$param]) {
dd("matched");
return true;
}
}
dd("no match");
return false;
});
$values = [
'player1' => 'test1',
'player2' => 'test2',
'winner' => 'test1'
];
$validationRules = [
'player1' => 'required',
'player2' => 'required',
'winner' => 'required|equals_one_of:player1,player2'
];
$validate = Validator::make($values, $validationRules);
// use your validator as normal.
dd($validate->validate());

Answer 2

Actually this rule should be registered with extendDependent to correctly resolve parameter names when used with arrays.
Final code:
class OneOfRule
{
public function validate($attribute, $value, $parameters, $validator) {
if(is_null($value)) return true;
foreach($parameters as $param) {
$other = Arr::get($validator->getData(), $param);
if ($value === $other) {
return true;
}
}
return false;
}
}
public function boot()
{
Validator::extendDependent('one_of', 'App\Http\Validation\Rules\OneOfRule#validate');
}