Eloquent Mutators and Accessors in Laravel

Eloquent Mutators and Accessors in Laravel

In Laravel, mutators and accessors allow you to alter data before it's saved to and fetched from a database. To be specific, the mutator allows you to alter data before it's saved to a database. On the other hand, the accessor allows you to alter data after it's fetched from a database.

In fact, the Laravel model is the central place where you can create mutator and accessor methods. And of course, it's nice to have all your modifications in a single place rather than scattered over different places.

Create Accessors and Mutators in a Model Class

As you're familiar with the basic concept of mutators and accessors now, we'll go ahead and develop a real-world example to demonstrate it.

I assume that you're aware of the Eloquent model in Laravel, and we'll use the Post model as a starting point of our example. If you haven't created the Post model yet, let's use the artisan command to create it.

php artisan make:model Post --migration

That should create a model file at app/Post.php as shown below.

<?php
 
namespace App;
 
use Illuminate\Database\Eloquent\Model;
 
class Post extends Model
{
    //
}

Let's replace the contents of that file with the following.

<?php
namespace App;
 
use Illuminate\Database\Eloquent\Model;
 
class Post extends Model
{
    /**
     * The attributes that should be mutated to dates.
     *
     * @var array
     */
    protected $dates = [
        'created_at',
        'updated_at',
        'published_at'
    ];
 
    /**
     * Get the post title.
     *
     * @param  string  $value
     * @return string
     */
    public function getNameAttribute($value)
    {
        return ucfirst($value);
    }
     
    /**
     * Set the post title.
     *
     * @param  string  $value
     * @return string
     */
    public function setNameAttribute($value)
    {
        $this->attributes['name'] = strtolower($value);
    }
}

As we've used the --migration option, it should also create an associated database migration. Just in case you are not aware, you can run the following command so that it actually creates a table in the database.

php artisan migrate

In order to run examples in this article, you need to create name and published_at columns in the post table. Anyway, we won't go into the details of the migration topic, as it's out of the scope of this article. So we'll get back to methods that we are interested in.

Firstly, let's go through the mutator method.

/**
  * Set the post title.
  *
  * @param  string  $value
  * @return string
  */
public function setNameAttribute($value)
{
    $this->attributes['name'] = strtolower($value);
}

As we discussed earlier, the mutators are used to alter data before it's saved to a database. As you can see, the syntax of the mutator method is set{attribute-name}Attribute. Of course, you need to replace {attribute-name} with an actual attribute name.

The setNameAttribute method is called before the value of the name attribute is saved in the database. To keep things simple, we've just used the strtolower function that converts the post title to lowercase before it's saved to the database.

In this way, you could create mutator methods on all columns of your table. Next, let's go through the accessor method.

If mutators are used to alter data before it's saved to a database, the accessor method is used to alter data after it's fetched from a database. The syntax of the accessor method is the same as that of the mutator except that it begins with the get keyword instead of the set keyword.

Let's go through the accessor method getNameAttribute.

/**
  * Get the post title.
  *
  * @param  string  $value
  * @return string
  */
public function getNameAttribute($value)
{
    return ucfirst($value);
}

The getNameAttribute method will be called after the value of the name attribute is fetched from the database. In our case, we've just used the ucfirst method to alter the post title.

And that's the way you are supposed to use accessors in your models. So far, we've just created mutator and accessor methods, and we'll test those in the upcoming section.

Date Mutators

In addition to the mutator we discussed earlier, the Eloquent model provides a couple of special mutators that allow you to alter data. For example, the Eloquent model in Laravel comes with a special $dates property that allows you to automatically convert the desired columns to a Carbon date instance.

In the beginning of this article, we created the Post model, and the following code was part of that class.

/**
 * The attributes that should be mutated to dates.
 *
 * @var array
 */
protected $dates = [
    'created_at',
    'updated_at',
    'published_at'
];

As you probably know, Laravel always creates two date-related fields, created_at and updated_at, with each database migration. And it converts those values to a Carbon date instance as well.

Let's assume that you have a couple of fields in a table that you would like to treat as date fields. In that case, you just need to add column names in the $dates array.

As you can see in the above code, we've added the published_at column in the $dates array, and it makes sure that the value of that column will be converted to a Carbon date instance.