How to include extra data in API response when user is authenticated

Question

I am creating a project where users can study with flash cards. I have an API from which users can retrieve decks of cards. Users who are not authenticated can still retrieve decks, but their learning progress is not stored in the database.

I would like for authenticated user to receive extra data in the response when retrieving flash cards from the API. More specifically, each card should have an extra 'study_at' field containing a date for when they should study that card next.

The 'study_at' date is stored in a pivot table called 'card_user'.

I have tried to modify the toArray() method on the Card model, but I don't know if that was the way to go.

This is the API endpoint:

Route::get('/decks', 'DecksController@index');

DecksController

class DecksController extends Controller
{
    public function index()
    {
        $decks = Deck::all();

        return new DeckCollection($decks);
    }

DeckCollection

class DeckCollection extends ResourceCollection
{
    public function toArray($request)
    {
        return parent::toArray($request);
    }
}

DeckResource

class DeckResource extends JsonResource
{
    public function toArray($request)
    {
        return [
            'id' => $this->id,
            'name' => $this->name,
            'cards' => new CardCollection($this->cards),
            'created_at' => $this->created_at,
            'updated_at' => $this->updated_at,
        ];
    }
}

CardCollection

class CardCollection extends ResourceCollection
{
    public function toArray($request)
    {
        return parent::toArray($request);
    }
}

CardResource

Here is where I want to include the 'study_at' date

class CardResource extends JsonResource
{
    public function toArray($request)
    {
        return [
            'id' => $this->id,
            'front' => $this->front,
            'back' => $this->back,
            // Include 'study_at' date here
            'created_at' => $this->created_at,
            'updated_at' => $this->updated_at,
        ];
    }
}

This is the response that I would like an authenticated user to recieve:

{
    "id": 1,
    "name": "Coffee Break French",
    "cards": [
        {
            "id": 1,
            "front": "Good morning",
            "back": "Bonjour",
            "study_at": "2019-05-26T15:00:00.000000Z"
            "created_at": "2019-04-14T21:04:05.000000Z",
            "updated_at": "2019-04-14T21:04:05.000000Z"
        },
        {
            "id": 2,
            "front": "Good afternoon",
            "back": "Bonne après-midi",
            "study_at": "2019-05-26T15:00:00.000000Z"
            "created_at": "2019-04-14T21:04:21.000000Z",
            "updated_at": "2019-04-14T21:04:21.000000Z"
        },
        {
            "id": 3,
            "front": "My name is John",
            "back": "Je m'appelle John",
            "study_at": "2019-05-26T15:00:00.000000Z"
            "created_at": "2019-04-14T21:04:37.000000Z",
            "updated_at": "2019-04-14T21:04:37.000000Z"
        }
    ],
    "created_at": "2019-04-14T21:03:38.000000Z",
    "updated_at": "2019-04-14T21:03:38.000000Z"
}

Answer 1

To include an attribute only under certain condition you should use conditional attributes:

class CardResource extends JsonResource
{
    public function toArray($request)
    {
        return [
            'id' => $this->id,
            'front' => $this->front,
            'back' => $this->back,
            // Include 'study_at' date here
            'study_at' => $this->when(auth()->user(), $this->study_at), // Retrieve your value through eloquent relation
            'created_at' => $this->created_at,
            'updated_at' => $this->updated_at,
        ];
    }
}

Answer 2

You may define a relationship with Laravel Eloquent:

class Card extends Model
{
   public function userCard() {
     // your relationship
   }
}

class CardResource extends JsonResource
{
    public function toArray($request)
    {
        return [
            'id' => $this->id,
            'front' => $this->front,
            'back' => $this->back,
            'study_at' => $this->userCard,
            'created_at' => $this->created_at,
            'updated_at' => $this->updated_at,
        ];
    }
}

See: https://laravel.com/docs/5.8/eloquent-relationships