How I can filter included resources by their fields

[sunnydesign]

Hi!
I want to filter included resources by their fields.
I tried to use withFilters() for the relationship fields, but it didn’t work:
For example, for this endpoints I want to filter related cart-items by their field practiceLocationId and to include them only:
http://localhost/api/v1/distributors?include=cart-items&filters[practiceLocationId]=89

My schema:

class DistributorSchema extends BaseSchema
{
...
    public function fields(): array
    {
          ...
          HasMany::make('cart-items')->withFilters(
              Where::make('practiceLocationId')
          )
          ...
    }
...
}

Big thanks for your answer.

[lindyhopchris]

Hi! I think you've created this issue in the wrong repo - from the code example I think you're using laravel-json-api/laravel?

In answer to your question though, there is nothing in the JSON:API spec that allows you to filter included resources. So this isn't supported. Filters apply to the primary set of resources, that appears in the data member of the document.

[sunnydesign]

It's so bad, my friend. I'm very disapointed. How can I solve this problem? Maybe you tell me a solution?

[sunnydesign]

You right, I use laravel-json-api/laravel. But I always write here :)

[lindyhopchris]

So you probably need to explain your use case as there's most likely a different way to do this. For example, you can filter a relationship endpoint, so you could do:

GET /api/v1/distributors/123/cart-items?filter[practiceLocationId]=456

[sunnydesign]

So, my goal is to receive in one request all distributors with their cart-items which deep related to distributors through product-distributors. Related cart-items must be filtered by practiceLocationId field, which belong cart-items resource. And distributors must be filtered by cart-items.practiceLocationId to.

[sunnydesign]

This is what I want to get with Eloquent:

$distributors = \App\Models\Distributor::whereHas('cartItems', function(Illuminate\Database\Eloquent\Builder $query) {
    $query->where('cart_item.practice_location_id', '=', 1);
});

foreach($distributors->get() as $distributor) {
    echo '<strong>distributor.id: ' . $distributor->id . '</strong>';
    echo '<br />';

    foreach ($distributor->cartItems()->where('cart_item.practice_location_id', '=', 1)->get() as $cartItem) {
        echo 'cartItem.id: ' . $cartItem->id . ' cartItem.practice_location_id: ' . $cartItem->practice_location_id;
        echo '<br />';
    }

    echo '<br />';
}

And result:

distributor.id: 30
cartItem.id: 222 cartItem.practice_location_id: 1
cartItem.id: 1 cartItem.practice_location_id: 1

distributor.id: 33
cartItem.id: 255 cartItem.practice_location_id: 1

distributor.id: 27
cartItem.id: 361 cartItem.practice_location_id: 1

distributor.id: 23
cartItem.id: 484 cartItem.practice_location_id: 1

[lindyhopchris]

So it's unrealistic to do that in one HTTP request using the JSON:API spec. Your example code of doing it with Eloquent has 1 database query to get the distributors, then an additional database query for each distributor to get the required cart items.

You've got an N+1 problem there, as the more distributors you have, the more database queries you'd get.

There's nothing in the JSON:API spec that allows you to do that at the moment in a single request. So you'd either need to accept multiple HTTP requests (which is along the lines of the N+1 problem you've got in the above example). Or you'd need to package the data up yourself in your own controller action. You can add custom actions, they are documented here:
https://laraveljsonapi.io/docs/1.0/routing/custom-actions.html

[sunnydesign]

Yes, i know about N+1, my code was for example. Anyway, my problem has already been solved by another way.
Big thanks for your answers.