Persisting Sessions in Slim - php

Question

I'm working on a web app using Slim, but I'm facing an issue with setting and persisting sessions.
Here is my index.php. I am trying to set a csrfToken key in the $_SESSION array, so that every request that is made through the app checks if the user has a csrfToken key, if not it will create one.
I'm just confused as to why it isn't persisting because on the next request it's gone. session_start is being called, it's being called automatically by '\Slim\Middleware\SessionCookie'.
Any ideas why this wouldn't be working? And would it be better to place this into middleware or use a hook?
use duncan3dc\Laravel\Blade;
use duncan3dc\Helpers\Env;
# TODO: Bootstrap the app. Move this to a seperate file. Dev only.
R::setup('mysql:host=localhost;dbname=somedb','user','pass');
$app = new \Slim\Slim(array(
'mode' => 'development',
'templates.path' => './views',
'cookies.encrypt' => true,
'cookies.secret_key' => 'mylongsecretkey',
'cookies.cipher' => MCRYPT_RIJNDAEL_256,
'cookies.cipher_mode' => MCRYPT_MODE_CBC
));
$app->add(new \Slim\Middleware\SessionCookie(array(
'expires' => '10 minutes',
'path' => '/',
'domain' => 'site.com',
'secure' => false, # Contact client to discuss using SSL
'httponly' => false,
'name' => '_sus',
'secret' => 'mylongsecretkey', # Do I need this twice?
'cipher' => MCRYPT_RIJNDAEL_256,
'cipher_mode' => MCRYPT_MODE_CBC
)));
# Not persisting ...
if(!isset($_SESSION['csrfToken']))
$_SESSION['csrfToken'] = hash("sha512",mt_rand(0,mt_getrandmax()));
# TODO: Bootstrap these.
require 'routes/index.php';
require 'routes/dashboard.php';
require 'routes/signup.php';
require 'routes/contactus.php';
require 'routes/privacypolicy.php';
require 'routes/testimonials.php';
require 'routes/login.php';
$app->run();

Answer 1

I figured out how to do it after reading more into hooks.
$app->hook('slim.before.router', function() use ($app){
if(!isset($_SESSION['csrfToken']))
$_SESSION['csrfToken'] = hash("sha512",mt_rand(0,mt_getrandmax()));
});