An Event Streaming Service (ESS) client behaviour.

Below is an example of an ESS client implementation:

defmodule MyApp.EventHandler do
  @behaviour PS2.ESS

  @impl PS2.ESS
  def handle_event(%{"event_name" => "PlayerLogin"} = event) do
    IO.puts "PlayerLogin: #{event["character_id"]}"
  end

  # Catch-all callback
  @impl PS2.ESS
  def handle_event(event) do
    IO.puts "Unhandled event: #{event["event_name"]}"
  end
end

You can then add it to your supervision tree:

defmodule MyApp.Application do
  use Application

  @impl Application
  def start(_type, _args) do
    subscription = PS2.ESS.Subscription.new(
      events: [PS2.player_login()],
      worlds: [PS2.connery(), PS2.miller(), PS2.soltech()],
      characters: :all
    )

    ess_opts = [
      subscription: subscription,
      callback_mod: MyApp.EventHandler,
      service_id: "YOUR_SERVICE_ID_HERE",
      # optional name to register the client process under
      name: MyApp.EventHandler
    ]

    children = [
      # ...
      {PS2.ESS, ess_opts},
      # ...
    ]

    opts = [strategy: :one_for_one, name: MyApp.Supervisor]
    Supervisor.start_link(children, opts)
  end
end

For more information about events and their payloads, see the Census documentation