get all atributes in nested object that have auto relationship - php

Question

I am creating a Rest API project that I have an Artist that have a Musical Genre object as an attribute, and I created these two classes like this:
Artist:
<?php
namespace App;
use Illuminate\Database\Eloquent\Model;
class Artist extends Model
{
    public $table = 'artist';
public $timestamps = false;
    
    protected $fillable = [
     'name', '...'
    ];
//...
public function musical_genre() {
        return $ this-> belongsTo (MusicalGenre::class, 'musical_genre');
    }
}
Musical Genre:
<?php
namespace App;
use Illuminate\Database\Eloquent\Model;
class MusicalGenre extends Model
{
public $table = 'musical_genre';
public $timestamps = false;
protected $fillable = [
'name', '...'
];
// ...
function parent_genre(){
return $this->hasMany(MusicalGenre::class, 'parent_genre');
}
}
As you can see, Genre Musical have an auto relationship, because an Genre Musical can have an Parent Genre. This works nice, but the response I get is like this:
{
"artist": [
{
"id": 14,
"name": "Britney Spears",
"musical_genre": {
"id": 4,
"name": "electropop",
"parent_genre": 1
}
}
]
}
But I wish it could be like this:
{
"artist": [
{
"id": 14,
"name": "Britney Spears",
"musical_genre": {
"id": 4,
"name": "electropop",
"parent_genre": {
"id:" 1,
"name": "pop"
}
}
}
]
}
In controller I have this line to call Artist with Genre:
$artist= Artist::with(['...', 'musical_genre'])->get();
I already tried to call it with musical_genre.parent_genre but I got a empty parent.
There is a way to make the response like I wished in Laravel, with all atributes and not only the id? I didnt found how can I do this in Laravel docs.
EDIT:
I already tried using
$artist->load('parent_genre');
too.
EDIT 2:
My last try was in show() method inside the controller, like this:
public function show($id)
{
$artist = Artist::with(['login', 'musical_genre'])->findOrFail($id);
$musical_genre = MusicalGenre::findOrFail($artist->musical_genre);
$parent_genre = MusicalGenre::findOrFail($musical_genre->parent_genre);
if ($parent_genre){
$musical_genre->parent_genre = $parent_genre;
}
$artist->musical_genre = $musical_genre;
return response()->json(['artist' => $artist], 200);
}
And I got the same response, just with the "parent_genre": 1. I tried to get only $musical_genre->parent_genre and I got this body:
"musical_genre": {
"id": 4,
"name": "electropop",
"parent_genre": {
"id:" 1,
"name": "pop"
"parent_genre": null
}
}
like I wished. Maybe it's some Laravel limitation, not showing artist->musical_genre->parent_genre full body?

Answer 1

Add a $with attribute to the MusicalGenre model like so:
class MusicalGenre extends Model
{
public $table = 'musical_genre';
public $timestamps = false;
protected $with = ['parent_genre:id,name'];
.....
}
See: https://laravel.com/api/5.6/Illuminate/Database/Eloquent/Model.html#property_with
When you call the MusicalGenre model, it loads the parent_genre automatically. The 'id,name' in it limits the retrieved model to the two fields, if you want to to load all, just use only 'parent_genre' only.
Simply call it this way and you have it loaded with the response:
$artist= Artist::with('musical_genre')->get();

Answer 2

Please try this for nested eager loading:
$artist= Artist::with(['musical_genre'=> function ($query) {
$query->with(['parent_genre']);
}])->get();