$xero = new PartnerApplication($config);
$oauth_session = getOAuthSession();
// If no session found
if ($oauth_session === null) {
$url = new URL($xero, URL::OAUTH_REQUEST_TOKEN);
$request = new Request($xero, $url);
//Here's where you'll see if your keys are valid. You can catch a BadRequestException.
try {
$request->send();
} catch (Exception $e) {
echo $e->getCode();
print_r($request->getResponse()->getOAuthResponse());
}
$oauth_response = $request->getResponse()->getOAuthResponse();
setOAuthSession($oauth_response['oauth_token'], $oauth_response['oauth_token_secret']);
printf('<a href="%s?oauth_token=%s">Click here to Authorize</a>', $xero->getAuthorizeURL(), $oauth_response['oauth_token']);
exit;
} elseif (isset($oauth_session['session_handle']) && !isset($oauth_session['expires'])) {
// If session is expired refresh the token
$url = new URL($xero, URL::OAUTH_ACCESS_TOKEN);
$request = new Request($xero, $url);
$request->setParameter('oauth_token', $oauth_session['token']);
$request->setParameter('oauth_session_handle', $oauth_session['session_handle']);
$request->send();
$oauth_response = $request->getResponse()->getOAuthResponse();
$expires = time() + intval($oauth_response['oauth_expires_in']);
setOAuthSession($oauth_response['oauth_token'], $oauth_response['oauth_token_secret'], $expires, $oauth_response['oauth_session_handle']);
$xero->getOAuthClient()->setToken($oauth_response['oauth_token'])->setTokenSecret($oauth_response['oauth_token_secret']);
} else {
$xero->getOAuthClient()->setToken($oauth_session['token'])->setTokenSecret($oauth_session['token_secret']);
if (isset($_REQUEST['oauth_verifier'])) {
