Laravel Serializer

Binds the JMS serializer library to Laravel and allows schemas to be defined according to normal Laravel configuration conventions.

Setup

To get Laravel Serializer ready for use in your project, take the usual steps for setting up a Laravel package.

• Add atrauzzi/laravel-serializer to your composer.json file.
• Run composer update at the root of your project.
• Edit your app/config/app.php file and add:
  • 'Atrauzzi\LaravelSerializer\ServiceProvider', somewhere near the bottom of your providers array
• Take a project-level copy of the configuration ./artisan config:publish atrauzzi/laravel-serializer

Note: Because this package does not perform any data storage, no migrations are required.

Configuring

Internally, the JMS serializer library makes use of metadata mappings. Normally these are configured via XML, YAML or annotations on the class being serialized. Laravel Serializer on the other hand is opinionated in that those definitions should be external to the business objects and kept in a format that is native to Laravel projects. As a result, the mappings are stored as part of the normal Laravel configuration array system.

If you wish to override this and configure serializer to use one of the default or a custom metadata driver factory you've made, all you have to do is re-bind JMS\Serializer\Builder\DriverFactoryInterface in the dependency injection container.

Mappings

If you open the copy of config.php that was created by the last step during setup, you will see it is already populated with a sample serializer mapping.

The mapping configuration schema is fairly simple and follows the form of:

[
    'mappings' => [
        'My\Namespace\Domain\User' => [
            'attributes' => [
                'id' => 'integer',
                'name' => [
                    'type' => 'string'
                ]
            ]
        ]
    ]
]

Every key under mappings is the fully qualified class name of the object that will be serialized. Every key under attributes within each class is the name of an attribute or mutator method (more on mutators in the usage section). The value specified under each key in mappings can be either an array, a string or unspecified. When the value is a string, that string will be the type used for that field. When the value is an array, multiple configuration directives can be specified for a single field. A key with no value will be given a best-guess default mapping configuration.

Usage

Because you're looking to serialize data, I'm going to assume that you already have some form of domain objects to work with in your project.

When performing serialization, each field in the mapping configuration indicates either a property or a mutator method, similar to the mutators that can be created on Eloquent models. That said, you can also define methods following the same convention if you are using any other ORM and/or POPOs.

Serialization is done by requesting an instance of JMS\Serializer\Serializer from the Laravel container. Once you have that instance, you can make use of it as per the normal JMS serializer docs.

Let's assume the following mapping configuration:

...
[
	'attributes' => [
		'firstName'
		'fullName' => [
			'type' => 'string'
		]
	]
]
...

And along with it, we'll also assume a business object has the following defined:

protected $firstName;

protected $lastName;

public function getFullNameAttribute() {
    return $this->userName . ' ' . $this->lastName;
}

Your controller will look something like this:

/** @var \JMS\Serializer\Serializer */
protected $serializer;

/**
 * @param \JMS\Serializer\Serializer $serializer
 */
public function __construct(
	Serializer $serializer
) {
	$this->serializer = $serializer;
}

public function myController() {
    // ...
	$serializedData = $this->serializer->serialize($myInstance, 'json');
    // ...
}

In this scenario, when serialzing to JSON, the following schema will be generated:

{
    "_type": "...",
    "first_name": "...",
    "full_name": "... ..."
}

As you can see, firstName was output, and fullName was mutated from firstName and lastName. But the standalone lastName attribute was not ouput because it was not specified in the mapping configuration. You may also observe that a _type field was generated as a convenience for any consumers that might be interested in mixed and polymorphic result sets.

Separation of Concerns

It might occur to you - especially if you are using Doctrine - that not all mutators belong on the classes that contain the data they're mutating. Often times, the mutation might be as a result of the circumstantial combination of two or more concerns. The best and most common example of this is when generating canonical URIs for objects. Ideally you should not be writing a getUri method on your models as that creates bad implicit dependencies.

In these situations, it makes more sense to leverage composition and create a class that can be made by Laravel's dependency injection container. Instances of this class have the instance of your model object assigned to them after having their __construct method called.

class PostSerializer {

    protected $uriGeneratorService;

    protected $post;

    public function __construct(UriGeneratorService $uriGeneratorService) {
        $this->uriGeneratorService = $uriGeneratorService;
    }

    public function setPost(Post $post) {
        $this->post = $post;
    }

    public function getUriAttribute() {
        return $this->uriGeneratorService->getUriForPost($this->post);
    }

}

Given the example above, additional properties from the Post itself could be output via mutators that pass the data upwards. In this sense, PostSerializer has become a kind of view that helps keep your domain class clean and portable by maintaining a sensible separation of concerns.

Eloquent

Laravel's default ORM is Eloquent and is a very convenient tool for manipulating queries and modeling data. As a side effect, it tends to bundle many non-domain concerns inside of model classes. Rather than ignore that useful metadata, this integration attempts to leverage it to minimize duplication of your efforts while authoring project code. Following is a list of some of the shortcuts you can enjoy if you're using Eloquent for data storage.

• Mutators are detected and used by Laravel Serializer when they are present.
• The $visible property on subclasses of Model is read during metadata setup. The most basic of setups is assumed for each field, however this might be sufficient for your needs and if so, means you will not need to create configuration mappings outside of your model classes.

Meta

The documentation and some of the functionality in this library is still evolving. If there's a feature or improvement that you would like to contribute or suggest, please don't hesitate to open a github ticket! :)

Credits

Laravel Serializer is created and maintained by Alexander Trauzzi