The Include Key Is Excluded If Include Function Returns null

[MannikJ]

I would like to include a belongsTo relation via fractal. If requested by the client, the key should always be present in the response object even if it is null.

public function includeUser(Model $model)
{
    if (!$model->user) {
        return null;
    }
    return $this->item($model->user, new UserTransformer);
}

In the above example the resulting array would not contain the user key, but the result should be like this:

[
    .
    .
    .
    'user' => null
    .
    .
    .
]

How can I convince fractal to include the key?

[matthewtrask]

I think you could do a ternary statement there, and if your relationship is null, call $this->null() I believe, and that should set the key there. I can mess with this some later.

[MannikJ]

Wow ;)

There is a transformer function null()? That's exactly what I have missed. Ternary statement or not doesn't matter. If this function exists, thank you!

[matthewtrask]

It should work. If you are adding a return type, use the ResourceInterface object and everything will work.

[matthewtrask]

Im going to close this for now, if you need more help feel free to open this issue again :)

[MannikJ]

I still couldn't figure out how to do it 😒
Just returning $this->null() from the include function leads to an empty array included in the request, but that's not what I want. I already managed to do it by making the model parameter in the transformer function optional and return the empty array from there.

It should work. If you are adding a return type, use the ResourceInterface object and everything will work.

Can you give a bit more detailed explanation?

I also found this issue #469 which seems to deal with the same problem. How long do you think it will take until the package covers that feature out of the box?

[matthewtrask]

I will see if I can get a working example later today.

[matthewtrask]

so @MannikJ just so I understand you have a model such as users and you want to be able to include the belongsTo relationship such as roles and have the key roles appear even if its null, but $this->null() doesn't give you what you want?

[MannikJ]

Your example is not very good, because I would not model a hasMany relation like roles with belongsTo. In my case there is an entity that has a user_id attribute and a belongsTo(User::class) relation.
When I transform this model and user_id is null, I still get an empty array instead of null when I use $this->null().
An empty array would probably be correct, if it is some kind of to many relation that is represented by a collection.

public function includeUser(Model $model)
{
    return $model->user_id
        ? $this->item($model->user, new UserTransformer)
        : $this->null();
}

[matthewtrask]

ok I will see what I can recreate.

[lpschz]

in the main transform method you can have 'user' => null
and in the include, simply return null too.

public function includeUser(Model $model)
{
    return $model->user_id
        ? $this->item($model->user, new UserTransformer)
        : null;
}