JsonDecoder for PHP

This package contains a JsonDecoder implementation that allows you to convert your JSON data into php class objects other than stdclass.

Installation

You can install the package via composer

composer require karriere/json-decoder

Usage

By default the Decoder will iterate over all JSON fields defined and will try to set this values on the given class type instance. This change in behavior allows the use of json-decoder on classes that use the magic __get and __set functions like Laravel's Eloquent models.

If a property equally named like the JSON field is found or a explicit Binding is defined for the JSON field it will be decoded into the defined place. Otherwise the property will just be created and assigned (you need the #[AllowDynamicProperties] attribute if you are on PHP 8.2.).

The JsonDecoder class can receive one parameter called shouldAutoCase. If set to true it will try to find the camel-case version from either snake-case or kebap-case automatically if no other binding was registered for the field and it will use an AliasBinding if one of the variants can be found.

A simple example

Assume you have a class Person that looks like this:

#[AllowDynamicProperties]
class Person
{
    public int $id;
    public string $name;
    public ?string $lastname = '';
}

The following code will transform the given JSON data into an instance of Person.

$jsonDecoder = new JsonDecoder();
$jsonData = '{"id": 1, "name": "John Doe", "lastname": null, "dynamicProperty": "foo"}';

$person = $jsonDecoder->decode($jsonData, Person::class);

Please be aware that since PHP 8.2. dynamic properties are deprecated. So if you still wish to have the ability to make use of those dynamic properties you have to add the PHP attribute AllowDynamicProperties to your class. If you are using PHP 8.2. (and greater) and don't use the AllowDynamicProperties attribute all dynamic properties will be ignored.

More complex use case

Let's extend the previous example with a property called address. This address field should contain an instance of Address. As of version 4 you can use the introduced method scanAndRegister to automatically generate the transformer based on class annotations. Since version 5 you can also make use of the property type instead of a class annotation.

class Person
{
    public int $id;
    public string $name;

    /**
     * @var Address
     */
    public $address;
    
    public ?Address $typedAddress = null;
}

For this class definition we can decode JSON data as follows:

$jsonDecoder = new JsonDecoder();
$jsonDecoder->scanAndRegister(Person::class);

$jsonData = '{"id": 1, "name": "John Doe", "address": {"street": "Samplestreet", "city": "Samplecity"}, , "typedAddress": {"street": "Samplestreet", "city": "Samplecity"}}';

$person = $jsonDecoder->decode($jsonData, Person::class);

Defining a Transformer

If you don't use annotations or need a more flexible Transformer you can also create a custom transformer. Let's look at the previous example without annotation.

class Person
{
    public int $id;
    public string $name;
    public mixed $address;
}

To be able to transform the address data into an Address class object you need to define a transformer for Person:

The transformer interface defines two methods:

• register: here you register your field, array, alias and callback bindings
• transforms: gives you the full qualified class name e.g.: Your\Namespace\Class

class PersonTransformer implements Transformer
{
    public function register(ClassBindings $classBindings)
    {
        $classBindings->register(new FieldBinding('address', 'address', Address::class));
    }

    public function transforms()
    {
        return Person::class;
    }
}

After registering the transformer the JsonDecoder will use the defined transformer:

$jsonDecoder = new JsonDecoder();
$jsonDecoder->register(new PersonTransformer());

$jsonData = '{"id": 1, "name": "John Doe"}';

$person = $jsonDecoder->decode($jsonData, Person::class);

Handling private and protected properties

As of version 4 the JsonDecoder class will handle private and protected properties out of the box.

Transforming an array of elements

If your JSON contains an array of elements at the root level you can use the decodeMultiple method to transform the JSON data into an array of class type objects.

$jsonDecoder = new JsonDecoder();

$jsonData = '[{"id": 1, "name": "John Doe"}, {"id": 2, "name": "Jane Doe"}]';

$personArray = $jsonDecoder->decodeMultiple($jsonData, Person::class);

Documentation

Transformer Bindings

The following Binding implementations are available

• FieldBinding
• ArrayBinding
• AliasBinding
• DateTimeBinding
• CallbackBinding

FieldBinding

Defines a JSON field to property binding for the given type.

Signature:

new FieldBinding(string $property, ?string $jsonField = null, ?string $type = null, bool $isRequired = false);

This defines a field mapping for the property $property to a class instance of type $type with data in $jsonField.

ArrayBinding

Defines an array field binding for the given type.

Signature:

new ArrayBinding(string $property, ?string $jsonField = null, ?string $type = null, bool $isRequired = false);

This defines a field mapping for the property $property to an array of class instance of type $type with data in $jsonField.

AliasBinding

Defines a JSON field to property binding.

Signature:

new AliasBinding(string $property, ?string $jsonField = null, bool $isRequired = false);

DateTimeBinding

Defines a JSON field to property binding and converts the given string to a DateTime instance.

Signature:

new DateTimeBinding(string $property, ?string $jsonField = null, bool $isRequired = false, $dateTimeFormat = DateTime::ATOM);

CallbackBinding

Defines a property binding that gets the callback result set as its value.

Signature:

new CallbackBinding(string $property, private Closure $callback);

License

Apache License 2.0 Please see LICENSE for more information.