Laravel API ResourceCollection WhenLoaded

Question

I try to include a relationship in my resource array if it has been eager loaded, but don't get it working.

Anyone has an idea, how I can check the relationships in the ResourceCollection?

Database schema looks like this:

Here is my Post Model

class Post extends Model
{
    function categories() {
        return $this->belongsToMany('App\Category');
    }
}

Here is my Category Model

class Category extends Model
{
    function posts() {
        return $this->belongsToMany('App\Post');
    }
}

Here is my Post Controller

Class PostController extends Controller
{
    public function index()
    {
        return new PostResourceCollection(Post::with("categories")->get());
    }
}

Here is my Post ResourceCollection

class PostResourceCollection extends ResourceCollection
{
    public function toArray($request)
    {

        return [
            'data' => $this->collection->transform(function($page){
                return [
                    'type' => 'posts',
                    'id' => $page->id,
                    'attributes'    => [
                        'name' => $page->title,
                    ],
                ];
            }),
            //'includes' => ($this->whenLoaded('categories')) ? 'true' : 'false',
            //'includes' => ($this->relationLoaded('categories')) ? 'true' : 'false',
        ];
    }
}

don't deal with Laravel anymore but found below answer. That seemed to work at this point in time — user7646471, Aug 15 '19 at 09:58
Then you may like to answer https://stackoverflow.com/questions/57478314/adding-filter-to-eloquent-resource-to-attach-relationship-conditionally/57486061?noredirect=1#comment101459987_57486061 — Prafulla Kumar Sahu, Aug 15 '19 at 10:01

score 2 · Answer 1 · answered Sep 30 '21 at 04:38

Maybe too late, below solution is a workaround for this case:

return [
    ...,
    'includes' => $this->whenLoaded('categories', true),
];

Loading custom attribute:

return [
    ...,
    'includes' => $this->whenLoaded('categories', fn() => $this->categories->name),
];

score 1 · Answer 2 · answered Feb 07 '18 at 17:05

1

You relationship is wrong, a post belongs to many categories while a category has many posts so change:

class Category extends Model
{
    function posts() {
        return $this->belongsToMany('App\Post', 'category_post');
    }
}

to

class Category extends Model
{
    function posts() {
        return $this->hasMany('App\Post', 'category_post');
    }
}

Now when you load the post you can load the categories also:

$posts = Post::with('categories')->get();

answered Feb 07 '18 at 17:05

Leo

7,274
5
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Thanks for your reply. Tested it and it does not have any effect. Just to be sure, loading of categories is not the issue. I just cannot reference it in my ResourceCollection. Like described here : https://laravel.com/docs/5.5/eloquent-resources#conditional-relationships – user7646471 Feb 07 '18 at 17:54
Normally a post belongs only to one category since the concept of categories is, that they are hierarchically. Otherwise they are tags. But lets go for the example: The relationships are correct in the question as you can read also in documentation https://laravel.com/docs/5.5/eloquent-relationships#many-to-many. Both ends are `belongsToMany` – common sense Feb 07 '18 at 21:04

score 0 · Answer 3 · edited Feb 25 '23 at 12:05

0

got it.. That was the missing piece. if anyone has a better solution for this it would be much appreciated.

foreach ($this->collection as $item) {
  if ($item->relationLoaded('categories')) {
    $included = true;
}

edited Feb 25 '23 at 12:05

francisco

1,387
2
12
23

answered Feb 07 '18 at 23:10

user7646471

352
3
11

Laravel API ResourceCollection WhenLoaded

3 Answers3