Shared Data

Often, you need to share data across all Inertia pages (e.g., the authenticated user, flash messages, or global app settings).

You can share data globally using the Inertia::share() method. The best place to do this is via a CodeIgniter Filter or BaseController.

namespace App\Controllers;

use Jengo\Inertia\Inertia;

class BaseController extends \CodeIgniter\Controller
{
    public function initController(\CodeIgniter\HTTP\RequestInterface $request, \CodeIgniter\HTTP\ResponseInterface $response, \Psr\Log\LoggerInterface $logger)
    {
        parent::initController($request, $response, $logger);

        // Share authenticated user
        if (auth()->loggedIn()) {
            Inertia::share('auth', [
                'user' => [
                    'id' => auth()->id(),
                    'username' => auth()->user()->username,
                ]
            ]);
        }

        // Share Flash Messages
        Inertia::share('flash', [
            'success' => session('success'),
            'error' => session('error'),
        ]);
    }
}

---

Using HandleInertiaRequests Middleware Filter

The recommended architectural approach is defining a dedicated filter class App\Filters\HandleInertiaRequests:

namespace App\Filters;

use CodeIgniter\Filters\FilterInterface;
use CodeIgniter\HTTP\RequestInterface;
use CodeIgniter\HTTP\ResponseInterface;
use Jengo\Inertia\Inertia;

class HandleInertiaRequests implements FilterInterface
{
    public function before(RequestInterface $request, $params = null)
    {
        Inertia::share([
            'auth' => [
                'user' => auth()->check() ? auth()->user() : null,
            ],
            'flash' => [
                'message' => session()->getFlashdata('message'),
                'error'   => session()->getFlashdata('error'),
            ],
        ]);
    }

    public function after(RequestInterface $request, ResponseInterface $response, $params = null)
    {
        return $response;
    }
}