Filter Objects

Moving filters out of the model

By default, the package looks for filters on the model itself. When a model has many filters, or when you want to keep them apart from the rest of the model, move them to a dedicated class and return it from getQueryStringObject():

use App\Filters\ProductFilters;
use Goodcat\QueryString\Traits\UseQueryString;
use Illuminate\Database\Eloquent\Model;

class Product extends Model
{
    use UseQueryString;

    public function getQueryStringObject(): object
    {
        return new ProductFilters;
    }
}

The filter object defines public methods with the same attribute and the same arguments as model filters:

namespace App\Filters;

use Goodcat\QueryString\Attributes\QueryString;
use Illuminate\Database\Eloquent\Builder;

class ProductFilters
{
    #[QueryString('category')]
    public function filterByCategory(Builder $query, string $category): void
    {
        $query->where('category', $category);
    }

    #[QueryString('min_price')]
    public function filterByMinPrice(Builder $query, string $price): void
    {
        $query->where('price', '>=', $price);
    }
}

The class needs no base class, interface or trait. Nothing else changes: you still call Product::query()->queryString($request).

Where filters are read from

The filters are read only from the object returned by getQueryStringObject(). Once you override it, methods tagged on the model are no longer called: keep all the filters of a model in one place.

getQueryStringObject() must stay public: the cache command calls it from outside the model.

Injecting dependencies

The object is created every time the scope runs. To inject services into its constructor, resolve it from the container:

public function getQueryStringObject(): object
{
    return app(ProductFilters::class);
}

Sharing filters between models

Since a filter object is a regular class, several models can return the same one, for example to share filters on columns they have in common. Each model is filtered independently, with its own query builder.