Data Transformers

Custom Data transformers on top of League/Fractal library.

See Fractal documentation at http://fractal.thephpleague.com/

Laravel 5.x

Install the saritasa/transformers package:

$ composer require saritasa/transformers

Add the TransformersServiceProvider service provider in config/app.php:

'providers' => array(
    // ...
    Saritasa\Transformers\TransformersServiceProvider::class,
)

This is required for localization to work properly.

Available transformers

IDataTransformer

Interface to unlink dependency from League/Fractal library. Ensure, that every transformer implementation in this library has this interface.

Example:

class AnotherTransformerWrapper implements IDataTransformer
{
    public function __construct(IDataTransformer $nestedTransformer) { ... }
}

BaseTransformer

When you just need to convert model to JSON response via Dingo/Api methods, and have no specific formatting requirements, you can just use BaseTransformer. It calls Arrayable->toArray() method. Thus, for Eloquent model result will consist of fields, described as $visible and not $hidden. Additionally converts fields, enumerated in $dates to ISO8061 format.

Example:

class User extends \Illuminate\Database\Eloquent\Model {
    // "full_name" is a property calculated from first_name and last_name
    protected $visible = ['full_name', 'created_at'];
    protected $hidden = ['email', 'password'];
    protected $dates = ['created_at', 'updated_at', 'birthday'];
}

class UserController extends BaseApiController {
    public function myProfile(): \Dingo\Api\Http\Response {
        $user = $this->user(); // Returns Eloquent model
        return $this->response->item($user, new BaseTransformer);
        // Output will be JSON
        // { "full_name": "Ivan Ivanov", "created_at": "2017-04-12T23:20:50.52Z" }
    }
}

$user = User::find($userId);

ObjectFieldsTransformer

Will output requested fields to result, regardless they described as $hidden or $visible in Eloquent model

Example:

class User extends \Illuminate\Database\Eloquent\Model {
    // "full_name" is a property calculated from first_name and last_name
    protected $visible = ['full_name', 'created_at'];
    protected $hidden = ['email', 'password'];
    protected $dates = ['created_at', 'updated_at', 'birthday'];
}

class UserController extends BaseApiController {
    public function myProfile(): \Dingo\Api\Http\Response {
        $user = $this->user(); // Returns Eloquent model
        $profileTransformer = new ObjectFieldsTransformer('first_name', 'last_name', 'email', 'birthday');
        return $this->response->item($user, $profileTransformer);
        // Output will be JSON
        // { "first_name": "Ivan", "last_name": "Ivanov", "email": "[email protected]", "birthday": "1985-04-12T00:00:00.00Z" }
    }
}

$user = User::find($userId);

CombineTransformer

Apply multiple transformers in order of arguments;

Example:

class UserProfileTransformer extends CombineTransformer
{
    public function __construct()
    {
        parent::__construct(
            new PreloadUserAvatarTransformer(),
            new PreloadUserSettingsTransformer()
        );
    }
}

LimitFieldsTransformer

Result will first apply ->toArray() method (which acts, respecting Eloquent's $visible and $hidden fields), then limits output to selected fields. This, hidden fields will not get in output, even if listed.

Example:

class User extends \Illuminate\Database\Eloquent\Model {
    protected $visible = ['full_name', 'created_at'];
    protected $hidden = ['email', 'password'];
    protected $dates = ['created_at', 'updated_at', 'birthday'];
}

class UserController extends BaseApiController {
    public function myProfile(): \Dingo\Api\Http\Response {
        $user = $this->user(); // Returns Eloquent model
        $publicProfileTransformer = new LimitFieldsTransformer('full_name', 'birthday');
        return $this->response->item($user, new BaseTransformer);
        // Output will be JSON
        // { "full_name": "Ivan Ivanov" }
    }
}

$user = User::find($userId);

Exceptions

TransformException

Should be thrown by class, implementing IDataTransformer, if it encounters data, that cannot be transformed.

Example:

function transform(Arrayable $data) {
    if (!$data->author) {
        new TransformException($this, "Author may not be empty");
    }
    // ...
}

TransformTypeMismatchException

Should be thrown, if your transformer expects model of a certain type, but gets another class.

class UserTransformer extends BaseTransformer {
    public function transform(Arrayable $model) {
        if (!$model instanceof User) {
            throw new TransformTypeMismatchException($this, User::class, get_class($model));
        }

        return transformUser($model);
    }

    private function transformUser(User $user) {
        ... // Handle strong-typed model
    }
}

Utility Classes

DtoModel

Allows you to use pure DTO models instead of Eloquent, while using Fractal for collection transformation.

Contributing

1. Create fork
2. Checkout fork
3. Develop locally as usual. Code must follow PSR-1, PSR-2
4. Run PHP_CodeSniffer to ensure, that code follows style guides
5. Update README.md to describe new or changed functionality. Add changes description to CHANGES.md file.
6. When ready, create pull request

Resources

• Bug Tracker
• Code
• Changes History
• Authors