Example fetching an OAuth access token in Magento2

magento2-get-access-token.php

// Using thephpleague/oauth1-client
// https://github.com/thephpleague/oauth1-client

require_once __DIR__.'/../../vendor/autoload.php';

// Create server
$server = new League\OAuth1\Client\Server\Magento(array(
    'identifier' => $data['consumerKey'],
    'secret' => $data['consumerSecret'],
    'callback_uri' => "http://mage-access.local/oath.php/",
));

$temporaryCredentials = $server->getTemporaryCredentials();

$server->getTokenCredentials($temporaryCredentials, $requestToken['oauth_token'], $requestToken['oauth_token_secret']);