Transformers

Whenever a resource converts the source model to an array, the source's attributes are retrieved by a transformer object.

The library ships with a default transformer that fetches attributes according to the following logic when accessing $this->attribute('attribute_name'):

• $source['attribute_name'] if the source model is an array,
• $source->toArray()['attribute_name'] if the source model has a toArray() method,
• $source->__toArray()['attribute_name'] if the source model has a __toArray() method,
• $source->getAttributeName() if the source model has such a method,
• $source->attributeName if the source has such a property (won't work via magic getter),
• $source->attribute_name property (also works via magic getter)

If this generic logic doesn't work with your type of source model then you can customize the transformer.

Customizing the Transformer

To use a custom transformer within your Resource class, set the transformer class in the static $transformer property:

class ShipmentTransformer extends Resource
{
    protected static $transformer = YourCustomTransformer::class;
}

This will cause the resource to use the custom transformer to access the source model's properties.

The transformer must implement the SourceTransformer interface which consists of 2 methods:

use Konekt\Resource\Contracts\SourceTransformer;

class YourCustomTransformer implements SourceTransformer
{
    public function toArray($source) : array
    {
        return (array) $source;
    }

    public function attribute(string $name, $source)
    {
        return $source->someCustomLogicToAccessAnAttribute($name);
    }
}

The toArray() method is used as a 'default' all-in one getter. It is used in case you don't explicitly set the fields in the toArray method of a concrete resource class.

The attribute() method is used to retrieve a single field/property/attribute identified by $name.

Both methods receive the source model as the $source argument.

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