What is the difference between Accessor/Mutators and Casting in laravel?

<?php
...
class User extends Model
{

        public function getIsAdminAttribute($value){
                return (bool)$value;
        }

        public function setIsAdminAttribute($value){
                $this->attributes['is_admin'] = (bool)$value;
        }
}

..

<?php
...
class User extends Model
{
        protected $casts = [
            'is_admin' => 'boolean',
        ];
}

I feel like they are both doing the same thing so what is the difference?

CodePudding user response：

An accessor transforms an Eloquent attribute value when it is accessed.

public function getFirstNameAttribute($value)
{
   return strtoupper($value);
}

Whenever you fetch a model, the property will be formatted/returned as per the accessor definition. Let's assume that a user's first_name is John. The above accessor will return the first_name in uppercase:

$user = User::findOrFail($id);
dd($user->first_name); // Will return 'JOHN' instead of 'John' because accessor

In the opposite way, a mutator will handle the property before being stored in your database

public function setFirstNameAttribute($value)
{
   $this->attributes['first_name'] = strtoupper($value);
}

Whenever you save a model, the property will be formatted as per the mutator definition. Let's assume that you pass a user's first_name as John. The above mutator will transform the first_name as JOHN before store:

$user = new User();
$user->first_name = 'John'; // It will be stored as JOHN because mutator
$user->save();

The attribute casting provides functionality similar to accessors and mutators. The main purpose is for using predefined casting methods instead of manually defining your own ones. IE, creating a date Carbon instance from a property:

protected $casts = [
    'birthday' => 'date',
];

Instead of

public function getBirthdayAttribute($value)
{
   return Carbon::create($value);
}

public function setBirthdayAttribute($value)
{
   $this->attributes['birthday'] = Carbon::create($value);
}

You can check docs at https://laravel.com/docs/8.x/eloquent-mutators#attribute-casting

CodePudding user response：

In addition to what Luciano wrote, accessors and mutators can do things that casting cannot. In the example below, we define a is_birthday attribute.

/**
 * @property Carbon date_of_birth
 * @property-read boolean is_birthday
 */
class Person extends Model {
  public function getIsBirthdayAttribute(){
    return $this->attributes['date_of_birth']->isToday();
  }
}

These derived attributes can be really helpful to abstract away common access patterns, like getting a full name from first and last names or computing invoice (sub)totals.