MessengerBot

Unofficial Facebook Messenger Platform chatbot client and webhook handler

MessengerBot covers majority of the functions to make calls to Facebook Messenger Platform endpoints.

MessengerBot library is designed for processing webhook events coming from Facebook with an event driven approach. It allows any number of subscribers to process same data without blocking.

Installation

The package can be installed by adding messenger_bot to your list of dependencies in mix.exs:

def deps do
  [{:messenger_bot, "~> 1.3.0"}]
end

Configuration

Facebook Messenger App and Page configurations

App and Page configurations can be done via config.exs and MessengerBot.Config module. Basic idea is to store apps and pages are type of MessengerBot.Model.{App, Page} types.

If you are using the app for a single page, config.exs seems to be right place but if you need to load app info from an external source, then use module functions to save your apps.

Note: App and Page keys must be atom() type like in the examples. For config.exs you can add apps and pages like below:

config :messenger_bot,
  fb_api_version: "v2.12",
  pages: %{
    "1881" => %{
      "1234" => %{
        id: "1234",
        name: "Demo Facebook Messenger Bot",
        access_token: "accesstokenforpage"
      }
    }
  },
  apps: %{
    "1881" => %{
      id: "1881",
      secret: "SECRET",
      setup_token: "Setup Token",
      access_token: "ATOKEN123"
    }
  }

Any time after loading messenger_bot, you can add more pages for an app.

pages = %{
  "1234" => %{
    id: "1234",
    name: "Demo Facebook Messenger Bot",
    token: "accesstokenforpage"
  },
  "1298" => %{
    id: "1298",
    name: "Demo Facebook Messenger Bot 1298",
    token: "accesstokenforpagefor1298"
  }
}

# Update configurations
MessengerBot.Config.save_pages(app_id, pages)

Details: https://hexdocs.pm/messenger_bot/1.0.0-beta10/MessengerBot.Config.html#save_pages/2

Any time after loading messenger_bot, you can save apps too.

apps = %{
  "1881" => %{
    id: "1881",
    secret: "SECRET",
    setup_token: "Setup Token",
    access_token: "ATOKEN123"
  }
}

# Update configurations
MessengerBot.Config.save_apps(apps)

Details: https://hexdocs.pm/messenger_bot/1.0.0-beta10/MessengerBot.Config.html#save_apps/1

Facebook App setup configuration

Add webhook endpoints to your router:

forward "/some-path-for-messenger_bot", to: MessengerBot.Web.Router

# The code above will add following routes
# -> GET   /some-path-for-messenger_bot/:app_id (Possible HTTP status codes: 200, 401, 404, 422, 500)
# -> POST  /some-path-for-messenger_bot/:app_id (Possible HTTP status codes: 200, 401, 404, 422, 500)
# -> MATCH /some-path-for-messenger_bot/:any (Possible HTTP status code: 404)

EventBus Configuration

Update your config.exs to add messenger_bot event topics and id generator for event_bus:

config :event_bus,
  ttl: 900_000_000,
  time_unit: :microsecond,
  id_generator: MessengerBot.Util.String,
  topics: [
    ##########################################################################
    # Webserver Topics
    ##########################################################################
    :mb_webserv_succeeded,
    :mb_webserv_payload_failed,
    :mb_webserv_erred,
    ##########################################################################
    # Webhook Topics
    ##########################################################################
    :mb_delivery_received,
    :mb_read_received,
    :mb_message_echo_received,
    :mb_message_attachments_received,
    :mb_message_quick_reply_received,
    :mb_message_received,
    :mb_optin_received,
    :mb_postback_received,
    :mb_referral_received,
    :mb_game_play_received,
    :mb_payment_received,
    :mb_checkout_update_received,
    :mb_pre_checkout_received,
    :mb_account_linking_received,
    :mb_policy_enforcement_received,
    :mb_app_roles_received,
    :mb_standby_received,
    :mb_pass_thread_control_received,
    :mb_take_thread_control_received,
    :mb_request_thread_control_received,
    :mb_na_received,
    :mb_app_setup_succeeded,
    :mb_app_setup_failed,
    ##########################################################################
    # Client Request Topics
    ##########################################################################
    :mb_attachment_upload_succeeded,
    :mb_create_message_creatives_succeeded,
    :mb_broadcast_message_succeeded,
    :mb_list_custom_labels_succeeded,
    :mb_fetch_custom_label_succeeded,
    :mb_delete_custom_label_succeeded,
    :mb_label_user_succeeded,
    :mb_unlabel_user_succeeded,
    :mb_list_custom_labels_of_user_succeeded,
    :mb_pass_thread_control_succeeded,
    :mb_take_thread_control_succeeded,
    :mb_request_thread_control_succeeded,
    :mb_fetch_secondary_receivers_succeeded,
    :mb_id_matching_succeeded,
    :mb_create_messenger_code_succeeded,
    :mb_fetch_messaging_feature_review_succeeded,
    :mb_fetch_insights_succeeded,
    :mb_set_messenger_profile_succeeded,
    :mb_reset_messenger_profile_succeeded,
    :mb_fetch_messenger_profile_succeeded,
    :mb_send_message_succeeded,
    :mb_unlink_account_succeeded,
    :mb_fetch_user_profile_succeeded,
    :mb_set_nlp_configs_succeeded,
    :mb_subscribe_to_page_webhooks_succeeded,
    :mb_unsubscribe_to_page_webhooks_succeeded,
    ##########################################################################
    :mb_attachment_upload_failed,
    :mb_create_message_creatives_failed,
    :mb_broadcast_message_failed,
    :mb_list_custom_labels_failed,
    :mb_fetch_custom_label_failed,
    :mb_delete_custom_label_failed,
    :mb_label_user_failed,
    :mb_unlabel_user_failed,
    :mb_list_custom_labels_of_user_failed,
    :mb_pass_thread_control_failed,
    :mb_take_thread_control_failed,
    :mb_request_thread_control_failed,
    :mb_fetch_secondary_receivers_failed,
    :mb_id_matching_failed,
    :mb_create_messenger_code_failed,
    :mb_fetch_messaging_feature_review_failed,
    :mb_fetch_insights_failed,
    :mb_set_messenger_profile_failed,
    :mb_reset_messenger_profile_failed,
    :mb_fetch_messenger_profile_failed,
    :mb_send_message_failed,
    :mb_unlink_account_failed,
    :mb_fetch_user_profile_failed,
    :mb_set_nlp_configs_failed,
    :mb_subscribe_to_page_webhooks_failed,
    :mb_unsubscribe_to_page_webhooks_failed,
    ##########################################################################
    :mb_attachment_upload_erred,
    :mb_create_message_creatives_erred,
    :mb_broadcast_message_erred,
    :mb_list_custom_labels_erred,
    :mb_fetch_custom_label_erred,
    :mb_delete_custom_label_erred,
    :mb_label_user_erred,
    :mb_unlabel_user_erred,
    :mb_list_custom_labels_of_user_erred,
    :mb_pass_thread_control_erred,
    :mb_take_thread_control_erred,
    :mb_request_thread_control_erred,
    :mb_fetch_secondary_receivers_erred,
    :mb_id_matching_erred,
    :mb_create_messenger_code_erred,
    :mb_fetch_messaging_feature_review_erred,
    :mb_fetch_insights_erred,
    :mb_set_messenger_profile_erred,
    :mb_reset_messenger_profile_erred,
    :mb_fetch_messenger_profile_erred,
    :mb_send_message_erred,
    :mb_unlink_account_erred,
    :mb_fetch_user_profile_erred,
    :mb_set_nlp_configs_erred,
    :mb_subscribe_to_page_webhooks_erred,
    :mb_unsubscribe_to_page_webhooks_erred]

Usage

Webhook handling

MessengerBot library handles allows you to handle all webhooks with subscription to the events.

How to subscribe to event topics?

messenger_bot package uses event_bus library to sent/process Messenger events. Please refer to event_bus docs to learn more. You can subscribe registered events. To subscribe all events you can use EventBus.subscribe({listener, [".*"]}) and to subscribe only specific topics then EventBus.subscribe({listener, ["mb_message_received$", "mb_postback_received$"]}). Please refer to event_bus library to documentation and Github wiki pages for more information.

Here is a sample echo bot consumer:

EventBus.subscribe({MessengerBot.Consumer.Echo, ["mb_message_received$"]})

defmodule MessengerBot.Consumer.Echo do
  @moduledoc """
  Sample consumer implementation which echos for MessengerBot message events
  """

  use GenServer

  @listener __MODULE__

  def process({:mb_message_received, _id} = event_shadow) do
    GenServer.cast(__MODULE__, {:echo, event_shadow})
  end

  # This func is not necessary, but just for an example
  def process({topic, id}) do
    EventBus.mark_as_skipped({@listener, topic, id})
  end

  def start_link do
    GenServer.start_link(__MODULE__, [], name: __MODULE__)
  end

  def init(_opts) do
    {:ok, []}
  end

  def handle_cast({:echo, {topic, id}}, state) do
    event = EventBus.fetch_event({topic, id})
    echo_back(event.data)
    EventBus.mark_as_completed({@listener, topic, id})

    {:noreply, state}
  end

  defp echo_back(%{app_id: app_id, page_id: page_id, messaging: messaging}) do
    message = prepare_payload(messaging)
    MessengerBot.send_message({app_id, page_id}, message)
  end

  defp prepare_payload(messaging) do
    %{
      "messaging_type" => "RESPONSE",
      "recipient" => %{"id" => messaging["sender"]["id"]},
      "message" => %{
        "text" => messaging["message"]["text"]
      }
    }
  end
end

Using Client to make HTTP request to Facebook endpoints

All MessengerBot client functions can be found on [https://hexdocs.pm/messenger_bot/1.0.0-beta10/MessengerBot.html#content).

Contributing

Issues, Bugs, Documentation, Enhancements

Create an issue if there is a bug.

Fork the project.

Make your improvements and write your tests(make sure you covered all the cases).

Make a pull request.

License

LGPLv3

Copyright (c) 2018 Mustafa Turan

MessengerBot is an Open Source project licensed under the terms of the LGPLv3 license. Please see http://www.gnu.org/licenses/lgpl-3.0.html for license text.

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.