Discord-Bot-Stream-Notes

Introduction

During the live stream we are going to be taking a look at the Discord.js NPM Module, which allows us to interact with the Discord API with ease.

To name but a few of the things we will be aiming to cover:

The fundamentals basics of building a Discord bot with Javascript and Node
Some of the common places you can host your bot and the limitations found in each host
My experiences, failures and Aha moments, through creating and maintaining several bot of all sizes and functionalities.
Interactive coding sessions, where you can suggest ideas and features, help us write the code and maybe even test it along the way.
We will also be taking questions throughout the live stream, so post them in ##mentor-live-coding-chat, remember no question is a silly question!

What is Discord.js

Discord.js takes a much more object-oriented approach than most other JS Discord libraries, making your bot's code significantly tidier and easier to comprehend. Usability, consistency, and performance are key focuses of discord.js, and it also has nearly 100% coverage of the Discord API. It receives new Discord features shortly after they arrive in the API.

Why Discord.js? Statistics

• Object-oriented

• Speedy and efficient

• Feature-rich

• Flexible

• 100% Promise-based

Future of Discord and its bots!

Over the last 5 years Discord has come a long way from the gamers voice and text chat application it started out as in 2015. It now has over 250 million registered users with 14 million of them sending 963 million message every single day.

Since Discord launched its official API back in April 2016, more than 3 million bots have been created and alone they have send over 9.5 billion messages.

Discord have recognised this and recently vaguely outlined their plans for a bright new future for bots and applications in this blog post. Myself and the team behind zeroBot are super excited about some of the changes being hinted at, as it will open up a bunch of new opportunities and different implemenations of the bots functionalities to make it more helpful and less spammy.

Hosting Options

There are a range of hosting options available for you to choose. Which one you should chose is going to vary on your needs and budget. Each of the options have their pros and cons, which you will need to weigh up against you requirements. In order of my personal favourites, the most common options are:

Digital Ocean

Personally his is my favourite method, although this option isn't for everyone due to the requirement for an understanding of devops, this method provides a lot of freedom, customisability and a complete tailored solution. You can also run multiple bots on the same droplet.

Pros	Cons
• Cheap	• Not Free
• Freedom	• Complex setup
• Allows dynamic files	• Complex CI/CD
• Multiple Bot per acc	• Security Risks

AWS and similar VPS services, would also fall into this category. And whilst hey are all valid options, I generally default to Digital Ocean due to familiarity and ease of use.

Heroku

I started out hosting my bots on Heroku and will occasionally still use Heroku for simple bots that are maybe under collaborative development, due to the simple CI/CD options available.

Pros	Cons
• Free	• No dynamic files
• Easy Setup	• Sleeps when inactive
• Easy CI/CD	• Less configurability
• Set it & forget it

Vercel (formerly now.sh/zeit)

I haven't really used this enough to really pass judgement and they have likely undergone major changes since I last used them. The service was fairly similar to Heroku, however the installation and configuration was more complex and time consuming than it needed to be.

Your own PC

Running the bot from your machine during development is one thing, However I really wouldn't recommend this option, especially long term.

Time To Code!

Coding a Discord bot is fairly straight forward, most people are often shocked at how little code is required to get a basic bot running. But before we look at any code, lets take a quick look at the requirements.

Requirements:

Javascript Knowledge - You can create Discord bots in a range of different languages, but we are going to focus on Javascript here. However, I would imagine some of it will translate across languages.

Obviously the better you know Javascript, the easier you will find coding your bot. But a basic understanding is all it takes. Zerobot v1 was born in my first month of learning Javascript!
A Code Editor - We will be using Visual Studio code, but Sublime or Atom etc will work just fine.
Node.js - You will need V6 or above, should you need to you can download it here.
Options Extras - Although this is outside the scope of this stream, if you require sound support (eg. Music bots) you will need some further packages. You can find more information about that in the TL;DR for you OS here

Event Based API

Discord explains their API in the following statement:

Discord's API is based around two core layers, a HTTPS/REST API for general operations, and persistent secure WebSocket based connection for sending and subscribing to real-time events. The most common use case of the Discord API will be providing a service, or access to a platform through the OAuth2 API.

What this essentially means is that, we program our bots to listen out for key events that we are interested in and consume the payload that is sent along side the event. This might sound complicated, but don't worry it will all make sense with the examples.

Once we consume the payload object and have run some logic against it, there are various endpoints of their restful API we can use to perform further actions. Lets take a look at a simple form bot.

A Simple Bot

The snippet below is a functional bot, in which it really only has two features:

We are listening out for Discord to send us the Ready Event, this just means that our bot has successfully authenticated using the credentials we provide it later on in the code. Once we recieve that event, we then console.log that we have logged in as the bot's name.
Secondly we are listening for a message event, so when ever a message gets sent in a channel the bot can read, discord will send us the message event. Inside this payload, we will be give an object (name here as msg) which will contain a bunch of data we can run logic on. In this case we are testing if the message is "ping", if it is we use a Discord.js Function to reply to the message as the bot.

const Discord = require('discord.js');
const client = new Discord.Client();

client.on('ready', () => {
  console.log(`Logged in as ${client.user.tag}!`);
});

client.on('message', msg => {
  if (msg.content === 'ping') {
    msg.reply('Pong!');
  }
});

client.login('token');

Getting Started

Lets get our workspace set up, so we can test out the above example and really get a feel for how it works.

Create a bot account & get your CONFIDENTIAL Discord Bot Token
Create a test server & add your bot too it. Ensuring it has sufficient permissions.
Open a new workspace in your editor and install the required packages.
Add in our sample code, test it and expand upon it.

During the stream, we will start implementing some commands and features to bring this bot to life and demonstrate the power and flexibility of the Discord API. We would love to make this part super interactive, please share any suggestions, features and tips. You will get a chance to help us write the code and test it out.

Resources

Handy Snippets

This snippet tries to generate a bot invite link and if it succeds will log the link in the console. I usually have this in the ready event.

  try {
     let link = await client.generateInvite(["ADMINISTRATOR"]);
     console.log(link);
  } catch (e) {
     console.log(e.stack);
  }

Why Discord.js?		Statistics
• Object-oriented
• Speedy and efficient
• Feature-rich
• Flexible
• 100% Promise-based

MattCSmith/Discord-Bot-Stream-Notes