Laravel 5 — How to build multiple Query Filters for Eloquent Model

QueryFilter.php

<?php

namespace app;
use Illuminate\Http\Request;
use Illuminate\Database\Eloquent\Builder;

abstract class QueryFilter
{
    protected $request;
    protected $builder;

    public function __construct(Request $request)
    {
        $this->request = $request;
    }

    public function customArrayFilter($var)
    {
        return ($var !== null && $var !== false && $var !== '');
    }

    public function apply(Builder $builder)
    {
        $this->builder = $builder;

        foreach ($this->filters() as $name => $value) {
            if (method_exists($this, $name)) {
                call_user_func_array([$this, $name], array_filter([$value, 'customArrayFilter']));
            }
        }

        return $this->builder;
    }

    public function filters()
    {
        return $this->request->all();
    }
}