Retrieve ghost authentification token in PHP

ghost-api.php

<?php

// Fill the informations below with your own credentials
$domain = 'http://my-domain.com';
$data = array(
  'grant_type' => "password",
  'username' => "[MY_MAIL_ADDRESS]",
  'password' => "[MY_PASSWORD]",
  'client_id' => "ghost-admin"
);
// Create map with request parameters

// Build Http query using params
$query = http_build_query($data);

// Create context resource for our request
$context = stream_context_create (array(
  'http' => array(
    'method'  => 'POST',
    'header'  => 'Content-type: application/x-www-form-urlencoded',
    'content' => $query
  )
));

// Read page rendered as result of your POST request
$result = file_get_contents(
  $domain . '/ghost/api/v0.1/authentication/token',
  false,
  $context
);

header("Content-type: application/json");
echo $result;