Fable.Router behaviour (Fable v0.0.1-alpha.2)

The router maps event names to callbacks handling the events.

In your router module you need to define a handler callback for each event you emit. By default MyApp.Events will be your router module.

def handlers do
  %{
    MyApp.Aggregate.EventHappened => &MyApp.Aggregate.event_happened/2
  }
end

Generally you don't want to have all those callbacks be public api though, which is why it's suggested to have those be private within e.g. your context modules and only make them available though a single function specifically for the use with Fable:

defmodule MyApp.Context do
  @behaviour Fable.Router

  def handlers do
    %{
      MyApp.Context.Aggregate.EventHappened => &event_happened/2
    }
  end

  defp event_happened(aggregate, event) do
    …
  end
end

defmodule MyApp.Events do
  use Fable.Events, repo: MyApp.Repo

  def handlers do
    %{}
    |> Map.merge(MyApp.Context.handlers())
    |> Map.merge(MyApp.AnotherContext.handlers())
  end
end

Summary

Types

t()

Callbacks

handlers()

This function returns a map of routings from event names to their handler callbacks.

Types

t()

@type t() :: module()

Callbacks

handlers()

@callback handlers() :: %{
  optional(Fable.Event.name()) =>
    Fable.Events.handler() | [Fable.Events.handler()]
}

This function returns a map of routings from event names to their handler callbacks.