#PHP HAL (Hypertext Application Language) Explorer#

This library provides a full featured API to discover a HAL (Hypertext Application Language) API via an expressive interface.

$posts = $resource->getLink('posts')->follow();

Features

• GuzzleHttp as default HTTP Client
• integrate custom HTTP clients easily
• human readable API
• Shipped with a simple default serializer for JSON responses
• Possibility to integrate custom serializers
• Fully tested
• Used in production projects

##Usage##

###1. Initiate the Explorer###

$explorer = new Explorer();
$explorer->setClientAdapter(new GuzzleClientAdapter(new Client()));
$explorer->setSerializer(new JsonSerializer());

If you want to use the the build in "GuzzleClientAdapter" you have to require guzzlehttp/guzzle manually in your composer project since guzzle is only suggested.

###2. Request your API###

$response = $explorer->request('GET', '/my/api/');

###3. Explore the response###

$resource = $explorer->explore($response);

###4. Discover your API###

$posts = $resource->getLink('posts')->follow();
foreach($posts as $post) {
    $publisher = $post->getLink('publisher')->follow();
    $company = $publisher->getLink('company')->follow();
}

The result of following a link is that the resolved resource is appended to the parent „$resource“ object („_embedded“). This allows you to access the linked resource without resolving the link again:

$posts = $resource->getEmbedded('posts');
foreach($posts as $post) {
    $publisher = $post->getEmbedded('publisher');
    $company = $publisher->getEmbedded('company');
}

##Custom HTTP Clients## Create a new class implementing the "ClientAdapterInterface" and return the response as PSR-7.

use Aeq\Hal\Client\ClientAdapterInterface;

class MyCustomClientAdapter implements ClientAdapterInterface
{
    public function request($method, $uri = null, array $options = [])
    {
        // call your custom client and return the response
    }
}

Set the custom client adapter to your explorer before using it.

$explorer->setClientAdapter(new MyCustomClientAdapter());

##Custom Serializers## Create a new class implementing the "SerializerInterface" and return the response.

use Aeq\Hal\Serializer\SerializerInterface;

class MyCustomSerializer implements SerializerInterface
{
    public function serialize($data)
    {
        // serialize your data: $data
    }

    public function deserialize($str)
    {
        // deserialize the string: $str
    }
}

Set the custom serializer to your explorer before using it.

$explorer->setSerializer(new MyCustomSerializer());

##Events## This library offers you some events to listen on. To use the event system you have to add the "EventManager" to your Explorer before using it.

$explorer->setEventManager(new EventManager());

To listen on a specific event you have to implement a Listener. A Listener is a PHP object with a public method "handle". As parameter your will get the triggered Event object.

class MyHandler
{
    public function handle(EventInterface $event)
    {
        // process your stuff
    }
}

###PostClientRequestEvent### This event is called on each executed request (after following a link or using the "request" method) and contains the complete PSR-7 response.

$explorer->listenOnEvent(PostClientRequestEvent::class, new MyHandler());