Calling shared functions that expects the conn interface from live_view

Questions / Help
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1

I’m currently building an authentication system in Phoenix LiveView where users can register and log in via a modal without a full page reload. My process involves logging the user in immediately after registration and then displaying a PIN verification modal.

In a traditional Phoenix controller, I’d typically use conn to manage session data, like this:

def log_in_user(conn, user, params \\ %{}) do
    token = Account.generate_user_session_token(user)
    user_return_to = get_session(conn, :user_return_to)

    conn
    |> renew_session()
    |> put_token_in_session(token)
    |> maybe_write_remember_me_cookie(token, params)
    |> redirect(to: user_return_to || signed_in_path(conn))
  end

However, I’m struggling to adapt this to LiveView. Since LiveView primarily works with socket instead of conn, I’m not sure how to properly manage the session and authentication state. I initially tried passing the socket to the above function, but it didn’t work as expected because it requires conn.

I understand that LiveView’s lifecycle means that data set on conn during the static render isn’t accessible in the live render. I’ve read that using assign_new to set session data or using the new on_mount callback in LiveView could help, but I’m unsure how to apply these concepts when my session management relies heavily on conn.

Has anyone successfully managed this transition from conn-based session handling to a LiveView-compatible approach? Any best practices for structuring the code so that it’s reusable across both traditional controllers and LiveViews?

Thanks in advance for any advice or examples!

2

You could use a server side session store, which would allow you to manage the session from LV. But with the default cookie based session storage you need a controller. You can only write to cookies when handling http requests, which you don’t have on a websocket based LV connection.

3

Thanks for the suggestion! I’ll give the server-side session store a try to see how it works. Do you have any recommendations for specific approaches? I’m curious to know if there are any potential pitfalls to watch out for.

4

I used Javascript hook to Solve the issue, here is the flow

User registers → LiveView handles registration and triggers the login event → JavaScript receives the event and makes an AJAX request to log in the user → After successful login, the PIN modal is shown

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