Let’s Build a Slackbot

Learning Objectives

Initialize a node project with npm init
Install dependencies with npm install --save
Explain what WebSockets are and why you would use them
Make requests to the Slack API using request module

Framing

What’s a Slackbot?

Bot users have many of the same qualities as their human counterparts: they have profile photos, names, and bios, they exist in the team directory, they can be direct messaged or mentioned, they can post messages and upload files, and they can be invited to and kicked out of channels and private groups.

The biggest difference between bot users and regular users is that instead of interacting with a team via one of Slack's mobile or desktop apps, bot users are controlled programmatically via a bot user token that accesses one or more of Slack's APIs.

source

What can a Slackbot do?

Anything
Deploy code
http://www.slackbotlist.com/

How SlackBots work

1. Obtain an API Token

Create a new bot here https://ga-students.slack.com/apps/new/A0F7YS25R-bots
Click "Add bot integration"
Copy API Token
- We’ll need this later

2. Retrieve WebSocket URL

What’s a websocket?

WebSockets provide a persistent two-way connection between the client and server. Instead of polling for data, or requesting it explicitly ($.ajax), the server can send events over the websocket connection.

This is ideal for realtime applications like:

Chat
Collaborative editing (Google Docs)
Multiplayer online games

$ mkdir my-slackbot
$ cd my-slackbot
$ npm init
$ npm install --save request
$ touch app.js

// app.js

var request = require("request");
var url = "https://slack.com/api/rtm.start?token=" + process.env.token;
request( url, function( err, response, body ){
    var websocketUrl = JSON.parse( body ).url;
    console.log(websocketUrl)
});

$ token=your-token-here node app.js

3. Connect to the WebSocket URL

$ npm install --save ws

// app.js

var request = require("request");
var WebSocket = require("ws");

var url = "https://slack.com/api/rtm.start?token=" + process.env.token;
request( url, function( err, response, body ){
    var websocketUrl = JSON.parse( body ).url;
    var ws = new WebSocket(websocketUrl);
});

4. Listen for and respond to events

// app.js

var request = require("request");
var WebSocket = require("ws");

var url = "https://slack.com/api/rtm.start?token=" + process.env.token;
request( url, function( err, response, body ){
    var websocketUrl = JSON.parse( body ).url;
    var ws = new WebSocket(websocketUrl);
    ws.on("message", function(message){
      console.log(message);
    })
});

You do: Interact with your slackbot

Send it a DM
Mention it in a channel it’s in
Type anything

How do you know when the message is a direct message?

Replying to a direct message

// app.js

var request = require("request");
var WebSocket = require("ws");

var url = "https://slack.com/api/rtm.start?token=" + process.env.token;
request( url, function( err, response, body ){
    var websocketUrl = JSON.parse( body ).url;
    var ws = new WebSocket(websocketUrl);
    ws.on("message", function(message){
      console.log(message);
      if(msg.type == "message" && msg.channel.substr(0,1) == "D"){
        reply(msg.channel, msg.text.split(" ").reverse().join(" "))
      }
    })
});

function reply(channel, message){
  var url = "https://slack.com/api/chat.postMessage?token=" + process.env.token + "&text=" + encodeURIComponent(message) + "&channel=" + channel;
  request(url, function(err,res,body){
    console.log(body)
  })
}

Simplifying things

GitHub created a bot service called Hubot - https://hubot.github.com/

Follow the setup instructions here - https://github.com/slackhq/hubot-slack#creating-a-new-bot
Create a new .js file in the scripts folder
https://github.com/github/hubot/blob/master/docs/scripting.md#hearing-and-responding

Don’t fear the coffeescript! It’s very similar to JavaScript, with a ruby-like syntax.

ga-wdi-lessons/slackbot