Getting a new accesstoken - php

Question

I am trying to retrieve a new access token with my refresh token. Before I run a script to retrieve a new access token I want to check if my access token is still valid.
I am trying to do this with exceptions:
try
{
// Connect
$session = new SoapClient("../webservices/session.asmx?wsdl", array('trace' => 1));
$result = $session->AccessTokenLogon($accessTokenparams);
}
catch (SoapFault $e)
{
// Check if AcccessToken returns TokenInvalid
if ($result->AccessTokenLogonResult == "TokenInvalid")
{
// AccessToken is not valid anymore
// ..
// Run script to get new access token
// ..
// $_SESSION["access_token"] = $access_token;
}
else
{
// AccessToken is valid
echo "AccessToken is valid";
}
}
finally
{
// Run script with valid AccessToken
global $result, $session;
$cluster = $result->cluster;
$qq = new domDocument();
$qq->loadXML($session->__getLastResponse());
$newurl = $cluster . '/webservices/processxml.asmx?wsdl';
try
{
$client = new SoapClient($newurl);
$header = new SoapHeader('http://www.website.com/', 'Header', array('AccessToken' =>$_SESSION["access_token"]));
}
catch (SoapFault $e)
{
echo $e->getMessage();
}
try
{
echo '<br /><br />XML Result:<br /><br />';
$xml = ""; // XML request
$result = $client->__soapCall('ProcessXmlString', array(array('xmlRequest'=>$xml)), null, $header);
}
catch (SoapFault $e)
{
echo $e->getMessage();
}
}
With a valid access token the script is working. The XML request is posted to the webservice.
The script is not working when the accesstoken is not valid anymore. The script stores the new accesstoken in the session: $_SESSION["access_token"] = $access_token; but is not running the 'finally' part after retrieving a new accesstoken.
Does someone know how I can fix this and run the 'finally' after retrieving a new accesstoken?