LINE API v2

line_bot.js

/*
  Usage: yarn add request

  ```
  var linebot = require('./line_bot');
  var LineBot = bot.new({
    channelSecret: <YOUR CHANNEL SECRET>,
    channelAccessToken: <YOUR CHANNEL ACCESS TOKEN>
  });
  ```
*/
var request = require('request');
var crypto;

var MAX_MESSAGES = 5;
var MAX_RECIPIENTS = 150;
var BASE_URL = 'https://api.line.me/v2/bot'

try {
  crypto = require('crypto');
} catch(e) {
  crypto = {};
  console.log('crypto support is disabled!');
}
var Bot = function(args){
  var headers = {
    'Content-type': 'application/json; charset=UTF-8',
    'Authorization': 'Bearer ' + args.channelAccessToken
  };
  API = {};
  API.validate_signature = function(req, res, buf, encoding) {
    var signature = req['headers']['x-line-signature'];
    var body = buf.toString(encoding);
    if (!signature || !body) {
      return false;
    }
    var hmac = crypto.createHmac('sha256', args.channelSecret)
    hmac.update(body, 'utf8');
    var hash = hmac.digest('base64');
    if (new String(hash).valueOf() === new String(signature).valueOf()) {
      return true;
    } else {
      throw new (function(){
        this.message = 'Authentication error';
        this.name = 'AuthenticationError';
        this.status = false;
      });
      return false;
    }
  };

  API.push = function(args){
    var options = {
      to: args.to,
      messages: args.messages
    };
    return sendMessages('/message/push', options);
  };

  API.multicast = function(args){
    var options = {
      to: args.to,
      messages: args.messages
    };
    return sendMessages('/message/multicast', options);
  };

  API.reply = function(args){
    var options = {
      replyToken: args.replyToken,
      messages: args.messages
    };
    return sendMessages('/message/reply', options);
  };

  API.profile = function(args){
    return new Promise(function(fullfil, reject){
      get({}, '/profile/' + args.userId, function(err, response, body){
        if (err) {
          reject(body);
          return;
        }
        try {
          fullfil(JSON.parse(body));
        } catch(e){
          console.log(e);
          fullfill(body);
        }
      });
    });
  };

  API.leave = function(args){
    var url;
    if (args.groupId) {
      url = '/group/' + args.groupId + '/leave';
    } else if (args.roomId) {
      url = '/room/' + args.roomId + '/leave';
    }
    return sendMessages(url, {});
  };

  function sendMessages(url, body){
    var options = {
      url: BASE_URL + url,
      headers: headers,
      json: true,
      body: body
    };
    return new Promise(function(fullfil, reject){
      if (body.messages && body.messages.length > MAX_MESSAGES) {
        reject('Too many messages (maximum: '+ MAX_MESSAGES +')');
        return;
      }
      if (body.to && body.to.constructor === Array) {
        if (body.to.length > MAX_RECIPIENTS) {//multicast
          reject('Too many recipients (maximum: ' + MAX_RECIPIENTS +')');
          return;
        }
      }
      request.post(options, function(err, response, body) {
        if (err) {
          reject(body);
          return;
        }
        fullfil(body);
      });
    });
  }

  function get(options, url, callback){
    var options = {
      url: BASE_URL + url,
      headers: headers
    };
    request(options, callback);
  }

  function post(body, url, callback){
    var options = {
      url: BASE_URL + url,
      headers: headers,
      json: true,
      body: body
    };
    request.post(options, function(err, response, body){
      if (callback) {
        callback({
          error: err,
          message: body
        });
      }
    });
  };
  return API;
};
module.exports = Bot;

with Express 4.x

var express = require('express');
var app = express();
var bodyParser = require('body-parser');
var bot = require('./line_bot');
var LineBot = new bot({
  channelSecret: '<YOUR CHANNEL SECRET>',
  channelAccessToken: '<YOUR CHANNEL ACCESS TOKEN>'
});

app.use(bodyParser.urlencoded({extended: true}));
app.use(bodyParser.json({
  verify: LineBot.validate_signature
}));

app.post('/callback', function(req, res){
  var json = req.body;
  var events = json.events;
  for (var i = 0, l = events.length; i < l; i++) {
    var e = events[i];
    LineBot.reply({
      replyToken: e.replyToken,
      messages: [{type: 'text', 'text': 'Yo!'}]
    });

    LineBot.profile({
      userId: json.events[0].source.userId
    })
    .then(function(profile){
      LineBot.push({
        to: profile.userId,
        messages: [{type: 'text', text: 'Yo, ' + profile.displayName + '!'}]
      });
    })
    .catch(function(e){
      console.log(e);
    });
  }
});

app.listen(process.env.PORT || 4649, function(){
  console.log("Server is running...");
});