How to handle sessions in Symfony?

In Symfony, sessions are handled using the Session component. Here is a general outline of how to work with sessions in Symfony:

Start a new session: To start a new session in Symfony, you can use the following code in your controller:

$session = $request->getSession();

$session->set('variable_name', 'variable_value');

Retrieve session variables: You can retrieve session variables using the following code:

$variable = $session->get('variable_name');

Remove session variables: To remove session variables, you can use the following code:

$session->remove('variable_name');

$session->clear();

Check if a session variable exists: To check if a session variable exists, you can use the following code:

if ($session->has('variable_name')) {
    // do something
}

Flash messages: Flash messages are messages that are stored in the session and displayed to the user on the next request. To set flash messages, you can use the following code:

$session->getFlashBag()->add('success', 'Message');

To access and display flash messages in your Twig template, you can use the following code:

{% for message in app.session.flashbag.get('success') %}
    <div class="alert alert-success">{{ message }}</div>
{% endfor %}

By following these steps, you can effectively handle sessions in Symfony.