I have the following live session:

  scope "/live", AmplifyWeb do

    live_session :default,
      layout: {AmplifyWeb.Layouts, :admin},
      on_mount: AmplifyWeb.Live.TokenValidator do

      live "/mailing-lists/:mailing_list_id/import-subscribers", ImportSubscribers
      live "/events/performance", EventPerformance

    end

  end

I want to validate a token from the query string in TokenValidator.on_mount and store the user_id from it in session so that it is available to all LiveViews within the live_session.

However, when I set anything on socket or session in on_mount, it is not available in the LiveView. I understand that’s because they are different instances of socket which makes sense. But how do I go about reading an initial value from query string and keeping it around in session or somewhere else where it can persist across LiveViews in the same live_session (and persist it across refreshes)?