slack-robot

Simple robot for your slack integration

slack-robot initially built to respond message from user with an action, then replying with a response. While hubot will do the job, it's too generic (no slack specific response like reaction, snippet, attachment, or listening to slack specific event). Using hubot also mean learning hubot specific command, using the right adapter, using the right slack-client, and patching them with slack specific event

While modularity is good, we're not sure about using multiple module with exponentially larger bug possibility (and also broader learning material). Because we are using it in critical application, we need to make sure that the API surface is as little as possible, with near perfect test coverage. With that in mind, we built slack-robot by wrapping "official" slack-client into much easier to consume request-response handling library.

Features

• Simple request response handler
• Normalize Slack API idiosyncrasy, for example:
  • listening to reaction_added event using Slack RTM will trigger event handler regardless the message and channel (even the channel the bot not joined)
  • uploading binary file is not possible (yet)
• Send response (or payload) without having to listen to event (external trigger)
• Access Control List (ACL) for each listener (only respond to message when fulfill specific criteria)
• Extensible via plug-ins (for example storing state)
• Complete control over what happen to your request and response

Installation

$ npm install slack-robot --save

Usage example

var SlackRobot = require('slack-robot');
var robot = new SlackRobot(process.env.SLACK_TOKEN);
 
// will post 'world' text as bot when receiving 'hello' message
// in channel, group, or direct message
robot.listen('hello', function (req, res) {
  return res.text('world').send();
});
 
// ignore message from '#general' channel, even if it matches the listener
robot.ignore('#general');
 
// start listening
robot.start();

Parameterized message

You can also listen to dynamic message by using parameterized message (usually called named-regexp), by using :name(REGEXP) syntaxes. All parameters will be available via req.params

// send 'get sheep from 2010' to your bot
robot.listen('get :animal([a-z\-]+) from :year([0-9]{4})', function (req, res) {
  console.log(req.params)
  // { animal: 'sheep', year: 2010 }
});

Pure regular expression (regexp) listener

Aside from named regexp (which uses a partial regexp match), you can use pure regexp inside your listener. The difference is, instead of getting an object in req.params, you get Array of regexp matches in req.matches

// send 'get sheep from 2010' to your bot
robot.listen(/get ([a-z]+) from ([0-9]{4})/, function (req, res) {
  // you don't have anything in named-param
  console.log(req.params)
  // {}
 
  // you use req.matches instead
  console.log(req.matches);
  // ['sheep', '2010']
})

Request & response life cycle

In slack-robot, receiving and sending message is handled via Request and Response object. Every time your bot receive a chat, you get Request object with typedef below

type Request = {
  message: {
    type: string
    value: {}
  },
  from: {
    id: string,
    name: string
  },
  to: {
    id: string,
    type: string, (channel, group, or dm)
    ?name: string // missing if direct message
  }
  params: {},
  matches: []
}

For example when you @anonymous send the bot @hola message get sheep from 2010 @hola in #general channel

robot.listen('get :animal([a-z\-]+) from :year([0-9]{4})', function (req, res) {
  console.log(req);
  // message: {
  //   type: 'text'
  //   value: {
  //     text: 'get sheep from 2010'
  //     mentioned: true
  //   }
  // },
  // from: {
  //   id: 'your_random_id',
  //   name: 'anonymous'
  // },
  // to: {
  //   id: 'random_channel_id',
  //   name: 'general',
  //   type: 'channel'
  // },
  // params: {
  //   animal: 'sheep',
  //   year: '2010',
  // },
  // matches: []
});

To respond a message, use res object. You can respond multiple times as you want

robot.listen('yo', function (req, res) {
  /**
   * Send text
   *
   * @param {string} text 
   */
  res.text('what\'s up?');
 
  /**
   * Send attachment
   *
   * @param {string} text in attachment
   * @param {Array<Object>|Object} 
   * @see https://api.slack.com/docs/attachments
   */
  res.attachment(text, attachment);
 
  /**
   * Send file
   *
   * @param {string} filename 
   * @param {string|ReadStream} content 
   * @see https://nodejs.org/api/fs.html
   */
  res.upload('snippet.txt', fs.createReadStream('snippet.txt'));
 
  /**
   * Add reaction to the message
   *
   * @param {string} reaction emoji
   */
  res.reaction(':+1:');
 
  /**
   * Always end your handler by returning res.send
   */
  return res.send();
});

Until you call res.send(), your message will not be sent. By calling res.send(), it will queue all your response and send them in series. To change this behavior, change concurrency property from robot:

// send 3 response in parallel (this will affect all listener)
// keep in mind that enabling concurrency means the order of the
// message is not guaranteed
robot.set('concurrency', 3);

Custom response target

To respond in another channel/im, simply pass the last argument to .text(), .attachment() or .upload(), with channel name #general, group name private-group, or user name @anon, or use an array of string to send multiple target:

robot.listen('yo', function (req, res) {
  res.attachment('here', attachment, '#general');
  res.upload('document.doc', file, '@anon');
  res.text('done!', ['#general', '@anon']);
 
  // end your request
  return res.send();
});

NOTE: You cannot use custom response target when adding reaction

Asynchronous response

Sometimes you want to do some asynchronous task before sending back response, you can use res.async() which accept a callback that receive send function as argument. To end your asynchronous task call send() without any argument. If your asynchronous task failed, call send() with an error object:

robot.listen('deploy', function (req, res) {
  res.text('executing scripts..');
 
  return res.async(function (done) {
    childProcess.exec('~/scripts/deploy --to production', function (err, stdout, stderr) {
      if (err) {
        // return to stop code for reaching res.text
        return done(err);
      }
 
      // use res.text like usual
      res.text('done, printing stdout:');
      res.text(stdout);      
      done();
    });
  // call .send() to send all previous response declared in asynchronous task
  }).send();
})

NOTE: Calling res.send() after res.async() doesn't send all the response, because res.send() is synchronous. Make sure you call res.async().send() to send the response

If you already use Promise, you can return your Promise chain instead of using res.async

// es2015 code style
robot.listen('deploy', (req, res) => {
  return deployer().then(output => {
    res.text('done, printing output:');
    res.text(output);
    return res.send();
  })
});

External trigger

You can also send message without having to listen to any message. This is particularly useful when combined with another service that run asynchronously (for example error reporting). Use robot.to() to get the response object you usually use when responding message

var ws = require('websocket');
 
ws.on('message', function (msg) {
  // robot.to() is asynchronous by nature because we need to make sure
  // the bot is connected before you able to send the message
  // hence the use of the callback to get the response object
  robot.to('@anon', function (res) {
    res.text('Hi anon, you got a message');
    res.text(msg);
    return res.send();
  });
});

NOTE: .reaction() and .async() cannot be used here

Handling the unexpected

slack-robot will emit event if something happened. Below is the list of events you can listen to:

• message_no_sender, when you receive a message without user information
• own_message, when you receive a message from bot itself
• ignored_channel, when you receive a message in channel that you ignore via robot.ignore
• no_listener_match, when you receive a message without matching listener
• response_failed, when failed sending a single response
• request_handled, when a request has been handled
• error, general error, usually if your listener callback has uncaught exception

To listen specific event, use robot.on(message, callback). Most event will receive message object, except response_failed and error event which receive error object instead, request_handled which receive request object, and message_no_sender which receive original message object from slack API

robot.on('error', function (err) {
  // print to stderr, or sent to error reporting service
  console.error(err);
});

Help command generator

When you have many listener, you sometimes forget all your listeners. You can see it by enabling help generator which will sent you all your listeners. Enable it using robot.set('help_generator', true) (it's disabled by default). It will add another listener that will listen to all text message containing "help". So if you send message to the bot "show help" or "help", it will send you the command list.

License

MIT