Serialization in Laravel

https://laravel.com/docs/8.x/eloquent-serialization#introduction

What is serialization?

It’s a way to store the values of an object into a text string format.
To convert our models, and our relationships to arrays or JSON.

When is it used?

Usually when we build JSON APIs, we will often need to convert our models and our relationships to arrays or JSON.

How does Laravel address this?

Eloquent includes convenient methods for:
- making these conversions
- controlling which attributes are included in your serializations.

Serializing To Arrays

How to convert to array just the loaded model attributes?

With the attributesToArray method:

$user = App\Models\User::first();
return $user->attributesToArray();

How to convert to array the loaded model’s attributes and its loaded relationships (eager loading)?

With the toArray method:

$user = App\Models\User::with('roles')->first();
return $user->toArray();

This method is recursive, so all attributes and loaded relations (eager loading) (including the relations of relations) will be converted to arrays.

Can I convert the entire collections of models to array?

yes

$users = App\Models\User::all();
return $users->toArray();

Serializing To JSON

How to convert to JSON the loaded model’s attributes and its loaded relationships?

With the toJson method:

$user = App\Models\User::find(1);
return $user->toJson();

This method is recursive, so all attributes and all relations (including the relations of relations) will be converted to JSON.
Relationships
- When an Eloquent model is converted to JSON, its loaded relationships will automatically be included as attributes on the JSON object.
- Also, though Eloquent relationship methods are defined using “camel case”, a relationship’s JSON attribute will be “snake case”.

Can I specify the Json encoding options supported in PHP? Yes

return $user->toJson(JSON_PRETTY_PRINT);

https://www.php.net/manual/en/function.json-encode.php

How to automatically call the toJson method?

Casting a model or collection to a string.
This will automatically call the toJson method on the model or collection.

$user = App\Models\User::find(1);
return (string) $user;

What happens when I return an Eloquent object directly from your application’s routes or controllers? (I didn’t fully understand this one…)

Since models and collections are converted to JSON when cast to a string, we can return Eloquent objects directly from your application’s routes or controllers.

I didn’t fully understand this one…

Route::get('users', function () {
  return App\Models\User::all();
});

How to hide attributes from the array / JSON?

Sometimes you may wish to limit the attributes, such as passwords, that are included in your model’s array or JSON representation.

To do so, add a $hidden property to your model:

<?php
namespace App\Models;
use Illuminate\Database\Eloquent\Model;

class User extends Model
{
    /**
     * The attributes that should be hidden for arrays and JSON.
     *
     * @var array
     */
    protected $hidden = ['password'];
}

Alternatively, you may use the visible property to define just the attributes that should be included in your model’s array and JSON representation

<?php
namespace App\Models;
use Illuminate\Database\Eloquent\Model;


class User extends Model
{
    /**
     * The attributes that should be visible in arrays and JSON
     *
     * @var array
     */
    protected $visible = ['first_name', 'last_name'];
}

Can I append extra custom attributes To JSON or Array when I cast my model even if they are not part of my model?

Yes, to do this in the model:

first define an accessor for the value.
then add the attribute name to the appends property.

<?php
namespace App\Models;
use Illuminate\Database\Eloquent\Model;

class User extends Model
{
    /**
     * Get the administrator flag for the user. (1)
     *
     * @return bool
     */
    public function getIsAdminAttribute()
    {
        return $this->attributes['admin'] === 'yes';
    }

    /**
     * The accessors to append to the model's array form. (2)
     *
     * @var array
     */
    protected $appends = ['is_admin'];
}

Note that attribute names are typically referenced in “snake case”, even though the accessor is defined using “camel case”:

Instead of using the $append property in the model to add the accessors and attributes. I can alternatively add them in the controller at runtime. Using one of this two methods:

append

This add just one attribute/property.

return $user->append('is_admin')->toArray();

setAppends
- This override the entire array of appended properties for a given model instance:
```
return $user->setAppends(['is_admin'])->toArray();
```

How to customize the format of the DATES that get serialised?

Change format of all the dates Overriding the serializeDate method. (in the model I guess)

class MyModel extends Eloquent {

    protected $dates = [
        'do',
        'date_closed',
        'file_stale_date'
    ];

    protected function serializeDate(\DateTimeInterface $date) {
        return $date->format('Y-m-d');
    }

}

This format the values of all the dates of the model when I retrieve the model like this:
- $post->toArray()
- $post->toJson()

Change format of specific dates Alternatively, You may customize the serialization format of individual Eloquent date attributes by specifying the date format in the cast declaration:

class MyModel extends Eloquent {

    protected $casts = [
        'birthday' => 'date:Y-m-d',
        'joined_at' => 'datetime:Y-m-d H:00',
    ];

}