Appending Eloquent Attributes/Modified Relation Date on Query Building / Code Optimization - laravel

Question

I'm looking for a solution to optimize my Code using Laravel Eloquent.
My issue is that I want to add Attributes conditionally, and this Attributes is basically the a transformed many-to-many relationship.
At the moment I have this in my controller (simplified):
<?php
namespace App\Http\Controller;
/**
* Class Category
*/
class Category extends Controller
{
/**
* #return Collection
*/
public function index()
{
return Category::withCount('countries')->get();
}
/**
* #param int $id
*
* #return Category
*/
public function show($id)
{
$result = Category::where('id', $id)
->with('countries')
->firstOrFail();
$result->countries_list = '';
return $result;
}
}
My Category model looks like this (simplified):
<?php
namespace App;
use Illuminate\Database\Eloquent\Model;
/**
* Class Category
*/
class Category extends Model
{
/**
* The accessors to append to the model's array form.
*
* #var array
*/
protected $appends = [
];
/**
* The attributes that should be hidden for arrays.
*
* #var array
*/
protected $hidden = [
'countries',
];
/**
* #return string
*/
public function getCountriesCountAttribute()
{
return trans_choice('labels.countries', $this->original['countries_count']);
}
/**
* #return
*/
public function getCountriesListAttribute()
{
return $this->countries->pluck('alpha_2');
}
/**
* Get the related Countries.
*/
public function countries()
{
return $this->belongsToMany(
Country::class,
'category_country',
'category_id',
'country_id'
);
}
}
The Country Model is just a list of Countries with id, name, the Alpha2 Code, etc. I can't use the protected $appends to add countries_list because than the the list would be always included.
I also can't change my Countries model because this is used in several other occurrences.
What I'm looking for is a way to optimize the code in the controller to this:
<?php
namespace App\Http\Controller;
/**
* #return Collection
*/
public function index()
{
return Category::withCount('countries')->get();
}
/**
* #param int $id
*
* #return Category
*/
public function show($id)
{
return Category::where('id', $id)
->withAttribute('countries_list') // An array of all country aplha 2 codes
->firstOrFail();
}

Answer 1

You can access the countries_list attribute after querying (don't include it in your query).
public function show($id)
{
$category = Category::findOrFail($id);
$list = $category->countries_list; // this calls getCountriesListAttribute()
}