client.php

<?php
class LightningChargeClient {
  protected $api;

  public function __construct($url, $api_token=null) {
    $this->api = new RestClient([
      'base_url' => rtrim($url, '/'),
      'curl_options' => $api_token ? [
        CURLOPT_USERPWD => 'api-token:' . $api_token
      ] : []
    ]);
  }

  /**
   * Create a new invoice.
   *
   * @param string|int $msatoshi
   * @param object $metadata
   * @return object the invoice
   */
  public function invoice($props) {
    $res = $this->api->post('/invoice', json_encode($props), [ 'Content-Type' => 'application/json' ]);

    if ($res->info->http_code !== 201) throw new Exception('failed saving invoice');

    return $res->decode_response();
  }

  /**
   * Fetch invoice by ID
   *
   * @param string $invoice_id
   * @return object the invoice
   */
  public function fetch($invoice_id) {
    $res = $this->api->get('/invoice/' . urlencode($invoice_id));
    if ($res->info->http_code !== 200) throw new Exception('failed fetching invoice');
    return $res->decode_response();
  }

  /**
   * Fetch all invoices
   *
   * @return array
   */
  public function fetchAll() {
    $res = $this->api->get('/invoices');
    if ($res->info->http_code !== 200) throw new Exception('failed fetching invoices');
    return $res->decode_response();
  }


  /**
   * Wait for an invoice to be paid.
   *
   * @param string $invoice_id
   * @param int $timeout the timeout in seconds
   * @return object|bool|null the paid invoice if paid, false if the invoice expired, or null if the timeout is reached.
   */
  public function wait($invoice_id, $timeout) {
    $res = $this->api->get('/invoice/' . urlencode($invoice_id) . '/wait?timeout=' . (int)$timeout);

    switch ($res->info->http_code) {
      // 200 OK: invoice is paid, return the updated invoice
      case 200: return $res->decode_response();
      // 402 Payment Required: timeout reached without payment, invoice is still payable
      case 402: return null;
      // 410 Gone: invoice expired and can not longer be paid
      case 410: return false;

      default: throw new Error('unknown status code ' . $res->info->http_code);
    }
  }

  /**
   * Register a new webhook.
   *
   * @param string $invoice_id
   * @param string $url
   * @return bool
   */
  public function registerHook($invoice_id, $url) {
    $res = $this->api->post('/invoice/' . urlencode($invoice_id) . '/webhook', [ 'url' => $url ]);
    if ($res->info->http_code !== 201)
      throw new Exception('register hook failed');
    return true;
  }
}