Question:

How to create a belongs to Many relationship with Laravel JSON:API?

Problem

I am familiar with creating a >Many To Many relationship using Laravel.

In my example, I have many resources that share many activities. I have been able to successfully create this relationship in their respective models:

// Activity.php

public function resources(): BelongsToMany

{

return $this->belongsToMany(Resource::class)->withTimestamps();

}

// Resource.php

public function activities(): BelongsToMany

{

return $this->belongsToMany(Activity::class)->withTimestamps()

->using(new class extends Pivot {

use HasUuids;

});

}

I'll then use the sync method to create the relationship.

$Ids = ['9a4cf36f-7683-4656-9653-9a01e1edbca1', '9a5225f0-31f6-40be-8863-6e8de61ef29f'];

$resource->activities()->sync($activityIds);

I'm attempting to create this same relationship using the >Laravel JSON:API package.

My ActivitySchema looks like this:

return [

...

BelongsToMany::make('resources')->readOnly(),

...

My ResourceSchema looks like this:

return [

...

ArrayList::make('activities'),

...

BelongsToMany::make('activities')->readOnly(),

...

Using Postman, when creating or updating a resource, my request body looks like this:

"attributes": {

"activities": ["9a4cf36f-7683-4656-9653-9a01e1edbca1", "9a5225f0-31f6-40be-8863-6e8de61ef29f"]

...

The error I'm currently getting when creating a new resource is:

"detail": "The field activities is not a supported attribute.",

Usually, that means I am missing the field on my Schema. I have verified that it's there, so I'm wondering if it's due to the relationship?

I have tried using a pivot model, but no success there either. Do I need to create a custom controller to handle this logic? I'm not having much luck finding any instructions on how to sync the models.

How can I create/sync the relationship using the JSON:API package?

Solution

You will want to check out >the tutorial as it has an example of a many-to-many relationship; Posts -- Tags.

In addition to the "attributes" you want to update in your resource, you'll also need to include the relationships.

For example, your resource PATCH request body will look something like this:

{

"data": {

"type": "resources",

"id": "676110ee-c302-4239-8eac-1f9e87ebaae8",

"attributes": {

"some_id": "01b77de1-d524-4794-af90-88f64dd68999",

"name": "My Resource",