route/redirect to index of same controller with data code igniter 4

Question

I want to redirect route to index of same controller. My scenario is after store of data in database I want to show message. Now I tried using FlashData like:

$this->session->setFlashdata('errmsg', json_encode(array('errstatus' => 'true' , 'msg' => $errorstring)));

So i tried accessing the data in view like :

<?php print_r($this->session->getFlashdata("errmsg"))?>

But it fails because the session variable is not existing. The way i am redirecting to same controller is like :

return redirect()->to('/register');

Now I am stuck in sending data to this redirect. I can do return view('pages/register', $this->session->get()); but its only a work around because if I do this the url still has the method store and it will show the error message everytime it loads.

Answer 1

I set up a little test to have a play with this...

I created a Controller (Home) to set up a flashData value with a link to another controller (Page) that sets up a second flashData value and attempts to displays both of them.

The Home Controller (app\Controllers\Home.php)

class Home extends BaseController
{
    protected $session;

    public function __construct() {
        $this->session = \Config\Services::session();
    }

    public function index()
    {
        $this->session->setFlashdata('errmsg_1','Error Message 1');
        echo '<a href="page">Click here to View the Flash Data</a><br>';
    }
}

The Page Controller (app\Controllers\Page.php)

class Page extends BaseController {
    protected $session;

    public function __construct() {
        $this->session = \Config\Services::session();
    }

    public function index() {
        echo __LINE__ . ' ' . __CLASS__ . ' ' . __METHOD__;
        $this->session->setFlashdata('errmsg_2','Error Message 2');
        return redirect()->to('/page/register');
    }

    public function register() {
        echo __LINE__ . ' ' . __CLASS__ . ' ' . __METHOD__;
        $page['error_message_1'] = $this->session->getFlashdata('errmsg_1');
        $page['error_message_2'] = $this->session->getFlashdata('errmsg_2');
        echo view('page_view', $page);
    }
}

And the View (app\Views\page_view.php)

<?php
/**
 * @var string $error_message_1
 * @var string $error_message_2
 */
echo '<br>';
echo 'Error 1 :';
echo ($error_message_1) ? $error_message_1 : 'I am Null'; // Expect this to be NULL?
echo '<br>';
echo 'Error 2 :';
echo ($error_message_2) ? $error_message_2 : 'I am Null'; // This should appear
echo '<br><a href="/home">Go Back Home</a><br>';

So the Home Controller loads up the FlashData for "errmsg_1" with a link to take us to the Page Controller.

Once at the Page Controller, the index sets an additional errmsg_2 and performs a redirect to the register method.

So after clicking the link from the Home Controller we arrive at the Page Controller which displays...

17 App\Controllers\Page App\Controllers\Page::register
Error 1 :I am Null
Error 2 :Error Message 2
Go Back Home

And on performing a Refresh on the Page Controller we get...

17 App\Controllers\Page App\Controllers\Page::register
Error 1 :I am Null
Error 2 :I am Null
Go Back Home

So the redirect does work using flashData.

The only downside is that you have to pass the flashdata value as a variable into the view to display it.