How to load relations with { json:api } Client?

Question

I am using the {json:api} Client to parse json into Eloquent like models.

I have two models, Congress and Speaker. A Congress has many Speaker.

This is what I was able to do:

$repository = app(App\Repositories\CongressRepository::class);
$document = $repository->all();

$document is a CollectionDocument with the following attributes:

I would like to get the speakers of the first Congress. This is what I tried

$congresses = $document->getData();
$congress = $congresses->first();
$congress->speakers // <- this is null!

Why is $congress->speakers null? I also tried to us $repository->all(['includes' => 'speakers']); but this makes no differences.

Answer 1

It seems that $congress->speakers was null because the relation was null:

I use this package to create the json output. Inside the Schema.php I had to add self::DATA to make the data visible, as explained in the docs.

public function getRelationships($resource, $isPrimary, array $includeRelationships)
{
    return [
        'speakers' => [
            self::SHOW_SELF => true,
            self::SHOW_RELATED => true,
            self::DATA => function () use ($resource) {
                return $resource->speakers;
            },
        ],
    ];
}

I still wonder if its possible to load the relation, if only the link is given in the API.