subway

# Subway

An minimalist event ~bus~ subway library for Elixir. (UNDER DEVELOPMENT)

## Simple usage:

### 1) Create your first event context with an event definition:
```elixir
defmodule YourApplication.UserEvents do
  use Subway

  defevent "listing_favorited" do # <- You can have multiple events like this
    field :user_id, :integer # <- Ecto.Schema api (id an timestamps are automatically defined)
    field :listing_id, :integer
  end
end
```

### 2) Define the subscribers(who will be notified when these event happen):
```elixir
defmodule YourApplication.UserEvents do
  alias YourApplication.Events.Subscribers

  use Subway,
    subscribers: [
      # Subscribers are simple modules that implement supported_event?/1 and handle_event/1
      Subscribers.PersistOnMongoDB,
      Subscribers.SendToHubspot,
      Subscribers.TriggerClientWebhook,
      Subscribers.EnqueueToRedis,
    ]

  # These fields will be merged to the event's fields defined in this context.
  @common_fields %{
    user_id: :integer
  }

  defevent ListingFavorited do
    field :listing_id, :integer, required: true
  end

  defevent SupportMessageSent do
    field :subject, :string
    field :content, :string
  end
end
```

### 3) Start tracking!
```elixir
  alias YourApplication.UserEvents

  # params = %{ user_id: 1, listing_id: 1 })
  case UserEvents.notify("listing_favorited", params) do
    {:ok, payload} -> "Yay! The event was broadcasted successfully"
    {:error, errors} -> "Could be validation errors"
  end
```

## Installation

If [available in Hex](https://hex.pm/packages/subway), the package can be installed
by adding `subway` to your list of dependencies in `mix.exs`:

```elixir
def deps do
  [
    {:subway, "~> 0.1.0"}
  ]
end
```