Laravel Custom Validation

app.php

'providers' => [
    
    // other providers

    // Add the new provider at the bottom
    'App\Services\Validation\ValidationServiceProvider',    

],

CustomValidation.php

<?php namespace App\Services\Validation;

use Illuminate\Support\Facades\DB;
use Illuminate\Validation\Validator;

class CustomValidation extends Validator {

    public function validateSumValues($attribute, $value, $parameters)
    {
        $sum = 0;
        foreach($parameters as $param) {
            $sum += Request::get($param);
        }
        
        return ($sum == $value);
    }
}

example.php

$rules = [
    'total' => 'sum_values:field1,field2',
];

$rules = [
    'total' => 'sum_values:field1,field2,field3,field4',
];

ValidationServiceProvider.php

<?php 

namespace App\Services\Validation;

use Illuminate\Support\ServiceProvider;

class ValidationServiceProvider extends ServiceProvider {

    /**
     * Register the service provider.
     *
     * @return void
     */
    public function register()
    {
    }

    /**
     * Boot the service provider.
     */
    public function boot()
    {
        $this->app->validator->resolver(function ($translator, $data, $rules, $messages)
        {
            return new CustomValidation($translator, $data, $rules, $messages);
        });
    }
}

Hi Bobby

I have added all the code as above but I am struggling to make it work, this is what I did:
I have 5 fields:
sec_discount - the other 4 must be equal to this one
vip_discount
rec_discount
ref_discount
cus_discount

In my request file I added this two lines:
'total' => 'sum_values:vip_discount,rec_discount,ref_discount,cus_discount', - (to get the value of the 4 fields)
'sec_discount' => 'required|numeric|same:total', - (to check that the two are the same)

It keeps giving error 'The sec discount and total must match' even if they do match.

So the sum_values validation is working only the same validation is not working?

You can easily check if these two fields are the same or not by doing this

dd(Request::get('total'), Request::get('sec_discount'));

If they are the same they should match!