fb-messenger-bot

Super lightweight Node.js / Express application that serves webhook for Facebook Messenger API.

Installing

Follow the guide at Facebook Messenger Platform - Getting Started. You should have a Facebook page and App set up before continuing.

Set up web access to your appication. HTTPS is prefered. If you don't have a personal preference, Heroku is well suited for quick deployment, development and experimentation.

Enter your app https address followed by /webhook in

Subscribe to messages and messaging_postbacks at least. Then whatever you set as Verify Token change it accordingly in server.js

//server.js
app.get('/webhook', function (req, res) {
  if (req.query['hub.verify_token'] === 'my_voice_is_my_password_verify_me') {
  ...

Commit, push... or whatever workflow you use to deploy. Click Verify and Save, it should proceed without error.

Select your page and obtain Page Access Token

Then copy it into:

//fbMessengerBot/config/appToken.js
module.exports = '<ACCESS TOKEN HERE>';

Save, commit, deploy. You should be up and running. Open up your Facebook page, click messages and start conversing with the bot...

Architecture

Whenever you write a message to your bot in Facebook Messenger, a POST request is made to https://yourappurl.com/webhook. App initially receives them in /fbMessengerBot/index.js

Then based on message type they are passed onto different handlers

/fbMessengerBot/handleMessages.js - generic messages typed by users
/fbMessengerBot/handlePostbacks.js - postbacks whenever user clicks a button with postback payload defined
/fbMessengerBot/handleOptins.js - user optins

Bot commands

Bot has few initial commands to play with

@bot debug on Turns on debug mode on, should echo back every message you write with full JSON message data.

@bot debug off Turns it off...

Sample messages

@bot reply with image

@bot reply with button template

@bot reply with generic template

@bot reply with receipt template

Composing Facebook Send API messages

Facebook API expects JSON messages in format described in Send API reference.

For convenience you can use fbMessage class in /fbMessengerBot/fbMessage/fbMessage.js Sample messages are assembled in /fbMessengerBot/handleBotCommands.js

Example:

var buttonTemplateReply = new fbMessage
    .ButtonTemplate("Which button would you like to press today?")
    .addButton({
        type:   "web_url",
        title:  "Visit www.nu.nl",
        url:    "http://www.nu.nl"
    })
    .addButton({
        type:       "postback",
        title:      "Postback to bot",
        payload:    "POSTBACK_SAMPLE_PAYLOAD"
    })
    .compose();

don't forget to add .compose() at the end, because that will return the final JSON and assign to the variable.

Available message types: