Get navToken for navionics webapi-v2 from api key.

getNAvToken.php

<?php

function get_navtoken() {
  // My api key.
  $api_key = 'Navionics_webapi_someNumber';
  $url = 'https://backend.navionics.io/tile/get_key/'.$api_key.'/webapiv2.navionics.com';
  // Authorized domain by the navionics.
  $referer = 'https://myhost.com';
  $ch = curl_init($url);
  curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
  curl_setopt($ch, CURLOPT_HEADER, 0);
  curl_setopt($ch, CURLOPT_REFERER, $referer);
  $navToken = curl_exec($ch);

  // Print {"errors":[{"code":7}]} 
  var_dump($navToken);
  $info = curl_getinfo($ch);

  // Print 403.
  var_dump($info['http_code']);

  curl_close($ch);
  if ($info['http_code'] == 200) {
    return $navToken;
  }else{
    return '';
  }
}