# 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.
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:
```php
class Person
{
public $id;
public $name;
}
```
The following code will transform the given JSON data into an instance of `Person`.
```php
$jsonDecoder = new JsonDecoder();
$jsonData = '{"id": 1, "name": "John Doe"}';
$person = $jsonDecoder->decode($jsonData, Person::class);
```
### More complex use case
Let's extend the previous example with a property called address. This address field should contain an instance of `Address`. In the prior versions of `json-decoder` it was necessary to define a custom `Transformer` to be able to handle this situation. As of version 4 you can use the introduced method `scanAndRegister` to automatically generate the transformer based on class annotations.
```php
class Person
{
public $id;
public $name;
/**
* @var Address
*/
public $address;
}
```
For this class definition we can decode JSON data as follows:
```php
$jsonDecoder = new JsonDecoder();
$jsonDecoder->scanAndRegister(Person::class);
$jsonData = '{"id": 1, "name": "John Doe", "address": {"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.
```php
class Person
{
public $id;
public $name;
public $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
```php
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:
```php
$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.
```php
$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](#fieldbinding)
- [ArrayBinding](#arraybinding)
- [AliasBinding](#aliasbinding)
- [DateTimeBinding](#datetimebinding)
- [CallbackBinding](#callbackbinding)
#### FieldBinding
Defines a JSON field to property binding for the given type.
**Signature:**
```php
new FieldBinding($property, $jsonField, $type);
```
This defines a field mapping for the property `$property` to a class instance of type `$type` with data in `$jsonField`.
#### ArrayBinding
Defines a array field binding for the given type.
**Signature:**
```php
new ArrayBinding($property, $jsonField, $type);
```
This defines a field mapping for the property `$property` to an array of class instance of type `$type` with data in `$jsonField`.
#### AliasBinding
Defines a JSON field to property binding.
**Signature:**
```php
new AliasBinding($property, $jsonField);
```
#### DateTimeBinding
Defines a JSON field to property binding and converts the given string to a `DateTime` instance.
**Signature:**
```php
new new DateTimeBinding($property, $jsonField, $isRequired = false, $dateTimeFormat = DateTime::ATOM);
```
#### CallbackBinding
Defines a property binding that gets the callback result set as its value.
**Signature:**
```php
new CallbackBinding($property, $callback);
```
## License
Apache License 2.0 Please see [LICENSE](LICENSE) for more information.