messenger-bot

A Node client for the Facebook Messenger Platform.

Requires Node >=4.0.0.

Installation

npm install messenger-bot

Example

See more examples in the examples folder.

Run this example in the cloud:

• Setup PAGE_TOKEN, VERIFY_TOKEN, APP_SECRET and start the example by Run > Start Messenger Echo Bot.
• Your Webhook URL is available at Preview > 3000 in the IDE.

const http = require('http')
const Bot = require('messenger-bot')

let bot = new Bot({
  token: 'PAGE_TOKEN',
  verify: 'VERIFY_TOKEN',
  app_secret: 'APP_SECRET'
})

bot.on('error', (err) => {
  console.log(err.message)
})

bot.on('message', (payload, reply) => {
  let text = payload.message.text

  bot.getProfile(payload.sender.id, (err, profile) => {
    if (err) throw err

    reply({ text }, (err) => {
      if (err) throw err

      console.log(`Echoed back to ${profile.first_name} ${profile.last_name}: ${text}`)
    })
  })
})

http.createServer(bot.middleware()).listen(3000)
console.log('Echo bot server running at port 3000.')

Usage

Functions

let bot = new Bot(opts)

Returns a new Bot instance.

opts - Object

• token - String: Your Page Access Token, found in your App settings. Required.
• verify - String: A verification token for the first-time setup of your webhook. Optional, but will be required by Facebook when you first set up your webhook.
• app_secret - String: Your App Secret token used for message integrity check. If specified, every POST request will be tested for spoofing. Optional.

bot.middleware()

The main middleware for your bot's webhook. Returns a function. Usage:

const http = require('http')
const Bot = require('messenger-bot')

let bot = new Bot({
  token: 'PAGE_TOKEN',
  verify: 'VERIFY_TOKEN'
})

http.createServer(bot.middleware()).listen(3000)

As well, it mounts /_status, which will return {"status": "ok"} if the middleware is running. If verify is specified in the bot options, it will mount a handler for GET requests that verifies the webhook.

bot.sendMessage(recipient, payload, callback)

Sends a message with the payload to the target recipient, and calls the callback. See Send API.

• recipient - Number: The Facebook ID of the intended recipient.
• payload - Object: The message payload. Should follow the Send API format.
• callback - Function: Called with (err, info) once the request has completed. err contains an error, if any, and info contains the response from Facebook, usually with the new message's ID.

bot.getProfile(target, callback)

Returns profile information of the target, called in the callback. See User Profile API.

• target - Number: The Facebook ID of the intended target.
• callback - Function: Called with (err, profile) once the request has completed. err contains an error, if any, and info contains the response from Facebook, in this format:

{
  "first_name": "Zach",
  "last_name": "Bruggeman",
  "profile_pic": "<url to profile picture>"
}

bot._handleMessage(payload)

The underlying method used by bot.middleware() to parse the message payload, and fire the appropriate events. Use this if you've already implemented your own middleware or route handlers to receive the webhook request, and just want to fire the events on the bot instance. See the echo bot implemented in Express for an example.

• payload - Object: The payload sent by Facebook to the webhook.

bot._verify(req, res)

The underlying method used by bot.middleware() for the initial webhook verification. Use this if you've already implemented your own middleware or route handlers, and wish to handle the request without implementing bot.middleware(). See the echo bot implemented in Express for an example.

• req - Request: The http request object.
• res - Response: The http response object.

Events

bot.on('message', (payload, reply))

Triggered when a message is sent to the bot.

• payload - Object: An object containing the message event's payload from Facebook. See Facebook's documentation for the format.
• reply - Function: A convenience function that calls bot.sendMessage, with the recipient automatically set to the message sender's Facebook ID. Example usage:

bot.on('message', (payload, reply) => {
  reply({ text: 'hey!'}, (err, info) => {})
})

bot.on('postback', (payload, reply))

Triggered when a postback is triggered by the sender in Messenger.

• payload - Object: An object containing the postback event's payload from Facebook. See Facebook's documentation for the format.
• reply - Function: A convenience function that calls bot.sendMessage, with the recipient automatically set to the message sender's Facebook ID. Example usage:

bot.on('postback', (payload, reply) => {
  reply({ text: 'hey!'}, (err, info) => {})
})

bot.on('delivery', (payload, reply))

Triggered when a message has been successfully delivered.

• payload - Object: An object containing the delivery event's payload from Facebook. See Facebook's documentation for the format.
• reply - Function: A convenience function that calls bot.sendMessage, with the recipient automatically set to the message sender's Facebook ID. Example usage:

bot.on('delivery', (payload, reply) => {
  reply({ text: 'hey!'}, (err, info) => {})
})