Posted By
Bajarangi soft ,
Posted On 10-09-2020
Custom Casts
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 cast value, while the set method should transform a cast value into a raw value that can be stored in the database. As an example, we will re-implement the built-in json cast type as a custom cast type:
<?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;
use App\Casts\Json;
use Illuminate\Database\Eloquent\Model;
class User extends Model
{
/**
* The attributes that should be cast.
*
* @var array
*/
protected $casts = [
'options' => Json::class,
];
}
Value Object Casting
You are not limited to casting values to primitive types. You may also cast values to objects. Defining custom casts that cast values to objects is very similar to casting to primitive types; however, the set method should return an array of key / value pairs that will be used to set raw, storable values on the model.
As an example, we will define a custom cast class that casts multiple model values into a single Address value object. We will assume the Address value has two public properties: lineOne and lineTwo:
<?php
namespace App\Casts;
use App\Address;
use Illuminate\Contracts\Database\Eloquent\CastsAttributes;
use InvalidArgumentException;
class Address implements CastsAttributes
{
/**
* Cast the given value.
*
* @param \Illuminate\Database\Eloquent\Model $model
* @param string $key
* @param mixed $value
* @param array $attributes
* @return \App\Address
*/
public function get($model, $key, $value, $attributes)
{
return new Address(
$attributes['address_line_one'],
$attributes['address_line_two']
);
}
/**
* Prepare the given value for storage.
*
* @param \Illuminate\Database\Eloquent\Model $model
* @param string $key
* @param \App\Address $value
* @param array $attributes
* @return array
*/
public function set($model, $key, $value, $attributes)
{
if (! $value instanceof Address) {
throw new InvalidArgumentException('The given value is not an Address instance.');
}
return [
'address_line_one' => $value->lineOne,
'address_line_two' => $value->lineTwo,
];
}
}
When casting to value objects, any changes made to the value object will automatically be synced back to the model before the model is saved:
$user = App\User::find(1);
$user->address->lineOne = 'Updated Address Value';
$user->save();
Inbound Casting
Occasionally, you may need to write a custom cast that only transforms values that are being set on the model and does not perform any operations when attributes are being retrieved from the model. A classic example of an inbound only cast is a "hashing" cast. Inbound only custom casts should implement the CastsInboundAttributes interface, which only requires a set method to be defined.
<?php
namespace App\Casts;
use Illuminate\Contracts\Database\Eloquent\CastsInboundAttributes;
class Hash implements CastsInboundAttributes
{
/**
* The hashing algorithm.
*
* @var string
*/
protected $algorithm;
/**
* Create a new cast class instance.
*
* @param string|null $algorithm
* @return void
*/
public function __construct($algorithm = null)
{
$this->algorithm = $algorithm;
}
/**
* 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, $attributes)
{
return is_null($this->algorithm)
? bcrypt($value)
: hash($this->algorithm, $value);
}
}
Cast Parameters
When attaching a custom cast to a model, cast parameters may be specified by separating them from the class name using a : character and comma-delimiting multiple parameters. The parameters will be passed to the constructor of the cast class:
/**
* The attributes that should be cast.
*
* @var array
*/
protected $casts = [
'secret' => Hash::class.':sha256',
];
Castables
Instead of attaching the custom cast to your model, you may alternatively attach a class that implements the Illuminate\Contracts\Database\Eloquent\Castable interface:
protected $casts = [
'address' => \App\Address::class,
];
Objects that implement the Castable interface must define a castUsing method that returns the class name of the custom caster class that is responsible for casting to and from the Castable class:
<?php
namespace App;
use Illuminate\Contracts\Database\Eloquent\Castable;
use App\Casts\Address as AddressCast;
class Address implements Castable
{
/**
* Get the name of the caster class to use when casting from / to this cast target.
*
* @return string
*/
public static function castUsing()
{
return AddressCast::class;
}
}
When using Castable classes, you may still provide arguments in the $casts definition. The arguments will be passed directly to the caster class:
protected $casts = [
'address' => \App\Address::class.':argument',
];