prisme-flow/nodes/bridge/bot/lib/facebook/messenger-bot.js

prisme platform flow engine

/**
 * Created by prisme.io on 09/06/2017.
 */

var url = require('url')
var inherits = require('util').inherits
var qs = require('querystring')
var EventEmitter = require('events').EventEmitter
var request = require('request')
var crypto = require('crypto')
var _ = require('underscore')
var _s = require('underscore.string')

function Bot (opts) {
  opts = opts || {}
  if (!opts.token) {
    throw new Error('Missing page token. See FB documentation for details: https://developers.facebook.com/docs/messenger-platform/quickstart')
  }
  this.token = opts.token
  this.app_secret = opts.app_secret || false
  this.verify_token = opts.verify || false
  EventEmitter.call(this)
}

inherits(Bot, EventEmitter)

_.extend(Bot.prototype, {

  getProfile: function (id) {
    var token = this.token
    return new Promise(function (resolve, reject) {
      request({
        method: 'GET',
        uri: 'https://graph.facebook.com/v2.6/' + id,
        qs: {
          fields: 'first_name,last_name,profile_pic,locale,timezone,gender',
          access_token: token
        },
        json: true
      }, function (err, res, body) {
        if (err) {
          reject(err)
        } else if (body.error) {
          reject(body.error)
        } else {
          resolve(body)
        }
      })
    })
  },

  setPersistentMenu: function (items, cb) {
    request({
      method: 'POST',
      uri: 'https://graph.facebook.com/v2.6/me/thread_settings',
      qs: {
        access_token: this.token
      },
      json: {
        'setting_type': 'call_to_actions',
        'thread_state': 'existing_thread',
        'call_to_actions': items
      }
    }, function (err, res, body) {
      if (body != null && body.error != null) {
        return cb(body.error.message)
      } else {
        cb(null)
      }
    })
  },

  sendMessage: function (recipient, payload, cb) {
    if (!cb) {
      cb = Function.prototype
    }
    request({
      method: 'POST',
      uri: 'https://graph.facebook.com/v2.6/me/messages',
      qs: {
        access_token: this.token
      },
      json: {
        recipient: {
          id: recipient
        },
        message: payload
      }
    }, function (err, res, body) {
      if (err) {
        return cb(err)
      }
      if ((body != null) && (_.isString(body))) {
        var errorJSON = null
        try {
          errorJSON = JSON.parse(body)
        } catch (e) {
          errorJSON = {error: 'Error parsing error payload from Facebook.'}
        }
        return cb(errorJSON.error)
      }
      cb(null, body)
    })
  },

  expressMiddleware: function (express) {
    var bot = this

    express.get('/bot/facebook/test', function (req, res) {
      bot._handleMessage({
        object: 'page',
        entry: [
          {
            id: 'not-a-valid-id',
            time: 1489742285434,
            messaging: [
              {
                sender: { id: null },
                recipient: { id: null },
                timestamp: 1489742285434,
                message: {
                  mid: 'not-a-valid-message-id',
                  seq: 42,
                  text: 'This is a test message (will not work with a Facebook Sender node)'
                }
              }
            ]
          }
        ]
      })
      res.send({status: 'ok'})
    })

    express.get('/bot/facebook/_status', function (req, res) {
      res.send({status: 'ok'})
    })

    express.get('/bot/facebook', function (req, res) {
      bot._verify(req, res)
    })

    express.post('/bot/facebook', function (req, res) {
      /* if (bot.app_secret) {
        var hmac = crypto.createHmac('sha1', bot.app_secret);
        // I think is demential to remove the rawBody from the request, if FB changes the way it serializes the
        // payload, this will break. The way the original body is rebuilt is uber-demential: since facebook encode
        // slash with \/ but not the stringify, then we need the replacer to do that, unfortunately passing '\/'
        // stringify encodes with '\\/'. This is the reason of the fixer and the useles tag like --slash--
        var originalBody = _s.trim(fixer(JSON.stringify(req.body, replacer, 0)));
        hmac.update(originalBody);
        //var signature = 'sha1=' + hmac.digest('hex');
        if (req.headers['x-hub-signature'] !== signature) {
          bot.emit('error', new Error('Message integrity check failed'));
          return res.send({status: 'not ok', error: 'Message integrity check failed'});
        }
      } */
      // send the message through
      bot._handleMessage(req.body)
      res.send({status: 'ok'})
    })
  },

  _handleMessage: function (json) {
    var _this = this
    // exit if empty body
    if (json != null && _.isArray(json.entry)) {
      var entries = json.entry
      entries.forEach(function (entry) {
        var events = entry.messaging
        events.forEach(function (event) {
          // handle inbound messages
          if (event.message) {
            _this.emit('message', event)
          }
          // handle postbacks
          if (event.postback) {
            event.message = {
              text: event.postback.payload
            }
            delete event.postback
            _this.emit('postback', event)
          }
          // handle message delivered
          if (event.delivery) {
            _this.emit('delivery', event)
          }
          // handle authentication
          if (event.optin) {
            _this.emit('authentication', event)
          }
          // handle account linking
          if (event.account_linking) {
            _this.emit('account_linking', event)
          }
        })
      })
    }
  },

  _verify: function (req, res) {
    var query = qs.parse(url.parse(req.url).query)

    if (query['hub.verify_token'] === this.verify_token) {
      return res.end(query['hub.challenge'])
    }

    return res.end('Error, wrong validation token')
  }

})

module.exports = Bot