facebook.ex

Facebook Graph API Wrapper written in Elixir. (documentation)

Installation

Add facebook.ex as a dependency in your mix.exs file.

defp deps do
  [{:facebook, "~> 0.24.0"}]
end

After you are done, run this in your shell to fetch the new dependency:

$ mix deps.get

Configuration

You can configure facebook.ex in your mix config.exs (or, if you're using the Phoenix Framework, in your config/dev.exs|test.exs|prod.exs, respectively) with the following keys, which state the library defaults:

config :facebook,
  app_id: nil,
  app_secret: nil,
  app_access_token: nil,
  graph_url: "https://graph.facebook.com",
  graph_video_url: "https://graph-video.facebook.com",
  request_conn_timeout: nil,
  request_recv_timeout: nil

For graph_url and video_graph_url, Facebook automatically uses the oldest active Graph API version available if you don't specify a version in the url. You may use versioned urls to pin your calls to a specific API versions (recommended), e.g. like so:

  graph_url: "https://graph.facebook.com/v2.11",
  graph_video_url: "https://graph-video.facebook.com/v2.8"

Note that you must not end the urls with a slash or the requests will fail (Facebook will report an error about unknown url components)!

app_id, app_secret and app_access_token do not need to be supplied if you are using no Graph API calls that require them (e.g. payment calls).

If you supply the app_secret, an appsecret_proof will be submitted along with the Graph API requests. The app_secret can be changed (or set) at runtime using Facebook.set_app_secret("<app secret>").

You can also configure facebook.ex library in runtime using {:system, _} tuples:

config :facebook,
  app_id: {:system, "APP_ID"},
  app_secret: {:system, "APP_SECRET"},
  app_access_token: {:system, "APP_ACCESS_TOKEN"},
  graph_url: {:system, "GRAPH_URL"},
  graph_video_url: {:system, "GRAPH_VIDEO_URL"},
  request_conn_timeout: {:system, :integer, "REQUEST_CONN_TIMEOUT"},
  request_recv_timeout: {:system, :integer, "REQUEST_RECV_TIMEOUT"}

Note that if you use {:system, _} (or {:system, :integer, _}) tuple but don't provide the corresponding environment variable application will crash on startup to prevent unexpected behaviour later.

Usage

1. Register an application on developer.facebook.com
2. Get an access_token from Facebook's Access Token Tool

Then you can get started with code.

Start an iex shell in your project folder:

$ iex -S mix

Then try some API calls:

iex(1)> Facebook.me("first_name", "ACCESSTOKEN")
{:ok, %{"first_name" => "Michael"}} # <--- that's the return value

iex(2)> Facebook.object_count(:likes, "262588213843476_801732539929038", "ACCESSTOKEN")
{:ok, 48} # <--- that's the return value

Contributing

We encourage contribution from anyone! If you've got an improvement to the documentation or feature you've implemented, please open a pull request. This project uses credo for code analysis. Running mix credo will give you a nice output which will tell you if any of the changes you've made aren't consistent with the rest of our codebase.

The Facebook Graph API is fairly large and as such we're not using every facet of it, so if you're not seeing an edge that is handled, please report an issue or open a pull request to add it.