feat: ability to load relationship in resource request when validating a model (not a relationship) about laravel

[lindyhopchris]

@paul-thebaud thanks for raising this issue, sorry I've only just seen it. (Must have missed the notification.)

I'm slightly unclear on the use case here, so if you could provide an example of what you're trying to do, that would help.

At the moment I would say it's not worth you submitting a PR. I've got quite a lot of major changes made ready for the v4 release. So I think the way forward is for me to understand your use case better, then I can see whether it needs to go into the current version or v4.

[paul-thebaud]

Hi @lindyhopchris, here is a simple (and dummy) example:
Let's take an API with two resources: applications and services. An application has many services. Users can attach services to their application, but only if they have access to these services.
I want to let users update their applications using a PUT request to /api/v1/applications/<ID>, and change the services inside this request. Service availability is check through a Laravel policy ServicePolicy. This is why I need to validate the relation values (eloquent instances) and not only the given Types/IDs.
I hope this will help.

[lindyhopchris]

@paul-thebaud sorry, just circling back to this.

The way to solve this is to write a Laravel validation rule: https://laravel.com/docs/10.x/validation#custom-validation-rules

And attach it to the services value. That will be an array of all the type and id combinations in the services array. The validation rule should then do a database query (or whatever else it is you do) to check whether those ids are ones the user has access to.

If you can't check that without loading the service models, your rule can pull all of those models out of the database using the whereKey() Eloquent query builder method, which is allowed to take an array of ids. Then iterate over them and check each one.