class RestExampleClientCalls

class RestExampleClientCalls {
    
    /**
     * The client used to send HTTP requests.
     *
     * @var \GuzzleHttp\ClientInterface
     */
    protected $client;
    
    /**
     * The headers used when sending HTTP request.
     *
     * The headers are very important when communicating with the REST server.
     * They are used by the server the verify that it supports the sent data
     * (Content-Type) and that it supports the type of response that the client
     * wants.
     *
     * @var array
     */
    protected $clientHeaders = [
        'Accept' => 'application/haljson',
        'Content-Type' => 'application/haljson',
    ];
    
    /**
     * The authentication parameters used when calling the remote REST server.
     *
     * @var array
     */
    protected $clientAuth;
    
    /**
     * The URL of the remote REST server.
     *
     * @var string
     */
    protected $remoteUrl;
    
    /**
     * The constructor.
     *
     * @param \GuzzleHttp\ClientInterface $client
     *   The HTTP client.
     * @param \Drupal\Core\Config\ConfigFactoryInterface $config_factory
     *   The Config Factory.
     */
    public function __construct(ClientInterface $client, ConfigFactoryInterface $config_factory) {
        $this->client = $client;
        // Retrieve the config from the configuration page set at
        // examples/rest_client_settings.
        $rest_config = $config_factory->get('rest_example.settings');
        $this->clientAuth = [
            $rest_config->get('server_password'),
            $rest_config->get('server_username'),
        ];
        $this->remoteUrl = $rest_config->get('server_url');
    }
    
    /**
     * Retrieve a list of nodes from the remote server.
     *
     * When we retrieve entities we use GET.
     *
     * @param int $node_id
     *   The ID of the remote node, if needed. If the ID is NULL, all nodes will
     *   be fetched.
     *
     * @return mixed
     *   JSON formatted string with the nodes from the remote server.
     *
     * @throws \RuntimeException
     * @throws \GuzzleHttp\Exception\GuzzleException
     */
    public function index($node_id = NULL) {
        // If the configured URL is an empty string, return nothing.
        if (empty($this->remoteUrl)) {
            return '';
        }
        $id = '';
        if (!empty($node_id) && is_numeric($node_id)) {
            $id = '/' . $node_id;
        }
        $response = $this->client
            ->request('GET', $this->remoteUrl . '/rest/node' . $id, [
            'headers' => $this->clientHeaders,
        ]);
        return Json::decode($response->getBody()
            ->getContents());
    }
    
    /**
     * Create a node on the remote server, using POST.
     *
     * @param array $node
     *   Contains the data of the node we want to create.
     *
     * @return \Symfony\Component\HttpFoundation\Response
     *   A HTTP response.
     *
     * @throws \InvalidArgumentException
     * @throws \GuzzleHttp\Exception\GuzzleException
     */
    public function create(array $node) {
        if (empty($this->remoteUrl)) {
            return new Response('The remote endpoint URL has not been setup.', 500);
        }
        // Build an array of options telling the remote server what type of content
        // we want to create, and give it a title. After that, we encode it all
        // to JSON.
        $request_body = json_encode([
            '_links' => [
                'type' => [
                    'href' => $this->remoteUrl . '/rest/type/node/' . $node['type'],
                ],
            ],
            'title' => [
                0 => [
                    'value' => $node['title'],
                ],
            ],
        ]);
        $response = $this->client
            ->request('POST', $this->remoteUrl . '/entity/node', [
            'headers' => $this->clientHeaders,
            'auth' => $this->clientAuth,
            'body' => $request_body,
        ]);
        // Validate the response from the remote server.
        if ($response->getStatusCode() != 201) {
            return new Response('An error occurred while creating the node.', 500);
        }
    }
    
    /**
     * Update (PATCH) a node on the remote server.
     *
     * You are encouraged to read the code and the comments in
     * RestExampleClientCalls::create() first.
     *
     * @param array $node
     *   Contains the data of the node we want to create.
     *
     * @return \Symfony\Component\HttpFoundation\Response
     *   A HTTP response.
     *
     * @throws \InvalidArgumentException
     * @throws \GuzzleHttp\Exception\GuzzleException
     */
    public function update(array $node) {
        if (empty($this->remoteUrl)) {
            return new Response('The remote URL has not been setup.', 500);
        }
        $request_body = json_encode([
            '_links' => [
                'type' => [
                    'href' => $this->remoteUrl . '/rest/type/node/' . $node['type'],
                ],
            ],
            'title' => [
                0 => [
                    'value' => $node['title'],
                ],
            ],
        ]);
        $response = $this->client
            ->request('POST', $this->remoteUrl . '/node/' . $node['nid'], [
            'headers' => $this->clientHeaders,
            'auth' => $this->clientAuth,
            'body' => $request_body,
        ]);
        if ($response->getStatusCode() != 204) {
            return new Response('An error occurred while patching the node.', 500);
        }
    }
    
    /**
     * Delete a node on the remote server, using DELETE.
     *
     * You are encouraged to read the code and the comments in
     * RestExampleClientCalls::create() first.
     *
     * @param array $node
     *   Contains the data of the node we want to create.
     *
     * @return \Symfony\Component\HttpFoundation\Response
     *   An HTTP response.
     *
     * @throws \InvalidArgumentException
     * @throws \GuzzleHttp\Exception\GuzzleException
     */
    public function delete(array $node) {
        if (empty($this->remoteUrl)) {
            return new Response('The remote URL has not been setup.', 500);
        }
        $response = $this->client
            ->request('DELETE', $this->remoteUrl . '/node/' . $node['nid'], [
            'headers' => $this->clientHeaders,
            'auth' => $this->clientAuth,
        ]);
        if ($response->getStatusCode() != 204) {
            return new Response('An error occurred while patching the node.', 500);
        }
    }

}