Reload Item View with a Button and send a variable to the session

Question

I try to add the possibility to my component to unlock content within the component item view.

If you watch the item view page, you see a description and an image and a little button. If you click the button, you reload the page and instead of the button you see the download url.

Now I wonder how to do this unlock button:

I have a simple form + submitbutton + hidden inputfield which reloads the page with an url-parameter. But is there another method which works without url-parameter? I would like to have this parameter invisible...

    <form>
        <input type="hidden" id="unlock" name="unlock">
        <button type="submit">Send</button>
    </form>

Thanks for letting me know ^^

Answer 1

Session variables should be set and redirects performed only by the controller. I assume you already have some controllers in your components. Add the task to an existing one or create a new one, whichever is more appropriate for your component.

The form:

use Joomla\CMS\HTML\HTMLHelper;
use Joomla\CMS\Router\Route;
use Joomla\CMS\Uri\Uri;

?>
<form method="post" action="<?php echo Route::_('index.php', false); ?>">

    <?php // Indicates the component to use ?>
    <input type="hidden" name="option" value="com_example">
    
    <?php // The controller and the method to execute ?>
    <input type="hidden" name="task" value="download.unlock">
    
    <?php // Set the redirect URL ?>
    <input type="hidden" name="return" value="<?php echo base64_encode(Uri::getInstance()); ?>">
    
    <?php // Pass the download ID, assuming there are multiple downloads and each needs to be unlocked separately ?>
    <input type="hidden" name="id" value="<?php echo $id; ?>">
    
    <?php // Renders CSRF token ?>
    <?php echo HTMLHelper::_('form.token'); ?>
    
    <button type="submit">Unlock</button>
</form>

The controller task:

public function unlock()
{
    // Check CSRF token.
    $this->checkToken();

    // Get the application.
    $app = Factory::getApplication();

    // Check that redirect URL is valid. Otherwise set it to index.php.
    $return = $this->input->post->get('return', '', 'BASE64');

    if (is_string($return))
    {
        $return = base64_decode($return);

        if (!Uri::isInternal($return))
        {
            $return = Route::_('index.php', false);
        }
    }
    else
    {
        $return = Route::_('index.php', false);
    }

    // Get the download ID.
    $id = $this->input->post->get('id', null, 'INT');

    // Check that download ID is a valid integer.
    if (!is_integer($id))
    {
        // Invalid ID provided, redirect back.
        $this->setRedirect($return, $app->getLanguage()->_('COM_EXAMPLE_DOWNLOAD_UNLOCK_INVALID_ID'));

        return;
    }

    // Set the session variable. Session key be anything, but make sure it's unique.
    $app->setUserState('com_example.download.unlock.' . $id, true);

    // Redirect back to download page.
    $this->setRedirect($return);
}