Laravel validate multiple exclusive requires - php

Question

I'm working with Laravel 5.5 and I'm trying to do some complex field validations and I don't seem to be able to find a solution for this.
I have three fields:
field_a (Boolean)
field_b (String)
field_c (String)
I need to validate that if field_a is true then field_b OR field_c are not empty.
I've tried to do something like:
'field_b' => 'required_with:field_a|required_if:field_c,',
'field_c' => 'required_with:field_a|required_if:field_b,',
But this way makes both fields required if field_a has been passed to the request.
Thank you in advance for your help.

Answer 1

I haven't been able to use Laravel's built-in validation system to do this kind of validation so I have created my own custom rule. I leave it here just in case somebody finds it useful.
class IfXOR implements Rule {
private $required;
private $fields;
/**
* Create a new rule instance.
*
* #param bool $required
* #param mixed $fields
* #return void
*/
public function __construct($required, $fields) {
$this->required = $required;
$this->fields = $fields;
}
/**
* Determine if the validation rule passes.
*
* #param string $attribute
* #param mixed $value
* #return bool
*/
public function passes($attribute, $value) {
if(!$this->required) return true;
if(!is_array($this->fields)) return $value || !empty($this->fields);
return $value || !empty(array_filter(function($f) { return !empty($f); }, $this->fields));
}
/**
* Get the validation error message.
*
* #return string
*/
public function message() {
return 'The validation error message.';
}
}