Attribute Casting with Laravel

Laravel is well known MVC framework written in PHP programming language. Over the years, it became the next tool in your belt for a plethora of programmers.

When we work with MVC, we have to deal with models and attributes as this is the layer that makes contact with our database.

Oftentimes, we need to cast the values received from the attributes to another form. For example, you have a field called is_admin in the database table with optional values 0 or 1. But you need to receive this value as a boolean field. Although this may be true that you can write an if condition and check if the value is equal to 0 then false, or if the value is equal to 1 then it is true.

But wherever you use this attribute you need to convert to boolean by a condition. In other words, you need to write 100 conditions if you need to use this code in 100 places.

Attribute Casting is coming in very handy in this matter. It’s almost the same as accessors or mutators without requiring you to write any extra functions.

For this, Laravel has the $casts property. Let’s see how it works:

<?php

namespace App;

use Illuminate\Database\Eloquent\Model;

class Product extends Model
{
    /**
     * The attributes that should be cast.
     *
     * @var array
     */
    protected $casts = [
        'price' => 'decimal:2',
        'status' => 'boolean',
        'is_available' => 'boolean'
    ];
}

Using this property the attributes are casted automatically, you will not need to make any changes manually or by a function.

The supported cast types are :

• array
• AsStringable::class
• boolean
• collection
• date
• datetime
• immutable_date
• immutable_datetime
• decimal:<digits>
• double
• encrypted
• encrypted:array
• encrypted:collection
• encrypted:object
• float
• integer
• object
• real
• string
• timestamp

Custom Casts

What if you are missing a cast option that is required for your next Laravel project. In that case, we can create our own cast option to suit our needs.

You may accomplish this by defining a class that implements the CastsAttributes interface.
Classes that implement this interface must define a get and set method.

The get method is responsible for transforming a raw value from the database into a casting value, while the set method should transform a casting value into a raw value that can be stored in the database.

For example, we will implement JSON cast type, which will decode from JSON and encode to JSON.

<?php

namespace App\Casts;

use Illuminate\Contracts\Database\Eloquent\CastsAttributes;

class Json implements CastsAttributes
{
    /**
     * Cast the given value.
     *
     * @param  \Illuminate\Database\Eloquent\Model  $model
     * @param  string  $key
     * @param  mixed  $value
     * @param  array  $attributes
     * @return array
     */
    public function get($model, $key, $value, $attributes)
    {
        return json_decode($value, true);
    }

    /**
     * Prepare the given value for storage.
     *
     * @param  \Illuminate\Database\Eloquent\Model  $model
     * @param  string  $key
     * @param  array  $value
     * @param  array  $attributes
     * @return string
     */
    public function set($model, $key, $value, $attributes)
    {
        return json_encode($value);
    }
}

Once you have defined a custom cast type, you may attach it to a model attribute using its class name:

<?php

namespace App\Models;

use App\Casts\Json;
use Illuminate\Database\Eloquent\Model;

class Product extends Model
{
    /**
     * The attributes that should be cast.
     *
     * @var array
     */
    protected $casts = [
        'options' => Json::class,
    ];
}