[8.x] Fix refresh during down

[driesvints]

This PR fixes an issue where the Refresh header was not set when an application is down with a specific template. There was a missing header at the bottom of the maintenance file.

Fixes #42208

[X-Coder264]

https://github.com/laravel/framework/blob/v9.10.1/src/Illuminate/Foundation/Http/Middleware/PreventRequestsDuringMaintenance.php#L74

Shouldn't the $this->getHeaders($data) call already add this header?

    /**
     * Get the headers that should be sent with the response.
     *
     * @param  array  $data
     * @return array
     */
    protected function getHeaders($data)
    {
        $headers = isset($data['retry']) ? ['Retry-After' => $data['retry']] : [];

        if (isset($data['refresh'])) {
            $headers['Refresh'] = $data['refresh'];
        }

        return $headers;
    }

[driesvints]

@X-Coder264 maintenance mode only reaches that code if there's no custom template. If there is, the request bubbles down to the lines I added.

[X-Coder264]

Are you saying that this block which is supposed to be reached when there is a custom template is never reached, thus being dead code?

            if (isset($data['template'])) {
                return response(
                    $data['template'],
                    $data['status'] ?? 503,
                    $this->getHeaders($data)
                );
            }

[driesvints]

@X-Coder264 I think you misunderstand how this works. The maintenance.php file is checked first, see https://github.com/laravel/laravel/blob/9.x/public/index.php#L19. Only if all the conditions in that file fail, the request is propagated to the app, otherwise it bubbles down to the lines I changed.

[X-Coder264]

Ah okay, yeah, I was missing that part, thanks for the explanation.