Welcome to our Discord Bots session! This session aims to get you to become more comfortable with how discord bots work, and allow you to make one for yourselves.
For those already comfortable, please skip to the final section where we have some challenges for you!
To begin, need to create and register your bot with the swan_hack server.
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Open up the Discord Developers Page
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Create a new application with the top-left "New Application" button. Call it something silly.
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Your application should appear in the "My Applications" list. Open it up, go to the "Bot" page, and click "Add Bot".
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Right below the username, you will see your "API" token. Make sure you
share that with everybodykeep it concealed! This is your "password" to the bot. -
Go to the "OAuth2 -> URL Generator" section
- Here, we will generate the link that will let me add your bot to our server, or any server for that matter.
- You first define the "scope" of the bot, for this you just need "Bot"
- You must then define what the bot needs access to. For this basic one, it simply needs "Read Messages/View Channels" and "Send Messages"
- After you ticked all the boxes, copy the url from the "Generated URL" field, and save it.
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Go to bot and scroll to "Privlidged Gateway Intents". Tick all the boxes there. This will allow the bot to function as an unverified bot. Remember to save your changes!
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Send the generated URL above to SatanicWomble#9932 (me), I will then notify you when I've added the bot. You should see the bot in the right pane of the
#sandboxtext channel.
Before you can get to programming, you actually need something to do it with. We will be using Python 3 with the Pycord library, but don't get intimidated if you're not familiar, that's the point of this session!
You will need:
- A text editor. A commonly suggested one is Visual Studio Code, but it really doesn't matter as long as you're comfortable with it. You can use windows notepad, if you're into that kind of thing.
- Python 3. We will only touch what we need in python, the rest is up to you. Follow the installation documents here.
- The Pycord library. Once you've installed python, follow this page to get it installed. Should be as easy as entering
py -3 -m pip install -U py-cordin Windows, orpython3 -m pip install -U py-cordin others. - Once you have everything above, you should be ready to go!
Now for the fun part, actually making the bot do something!
Let's take apart the following modified example from the official quickstart guide.
# Import the pycord library into your runtime.
import discord
# Assign the discord client to an object, we call client.
# All discord actions will act on this variable.
client = discord.Client()
# This is a function.
# It executes whenever the bot has successfully initialised.
# In this case, it simply prints "We have logged in ..." to the terminal.
@client.event
async def on_ready():
print(f"We have logged in as {client.user}")
# This function executes whenever the bot has received a new message.
# This can be a DM or a message in a channel that the bot can see.
@client.event
async def on_message(message):
# If the message starts with $hello, respond with Hello!
if message.content.startswith("$hello"):
await message.channel.send("Hello!")
# Required to run the bot, make sure to replace <YOUR_API_TOKEN>!
client.run("<YOUR_API_TOKEN>")
# (we actually recommend you store your token in a file, so that if you ever publish your code you won't publish the token)Chuck the above into your text editor, replace <YOUR_API_TOKEN> with the token (password) saved earlier, and save it to disk as "firstbot.py".
Now to run your program, execute the following command:
- For Windows:
py firstbot.py - For others
python firstbot.py
Try sending $hello in #sandbox!
The basic example had a simple response to a simple message. This is nice, but we'd like to make it do something more useful. The following sections go over some of the important mechanisms in the Pycord API.
The bot's on_message function activates on every message, including those from other bots and itself. It's best to design precautions of this into the start of the function.
To stop execution if the message came from the bot itself:
if message.author == client.user:
returnOr, to stop execution if the message came from a bot (including itself):
if message.author.bot:
returnEvery message the bot receives, goes through the on_message function. This includes channel messages and DMs.
The message is represented with a Message object. You can access important information and perform function with that object, including:
- Content string with
content - User object with
author - Creation time/date with
created_at - Others documented here
For example, if you wanted to print a message if a user with a specific name messaged it:
if message.author.name == 'SatanicWomble':
print('ughh my boss is bugging me again')If you then wanted to reply to that message:
await message.reply("Hey Boss, I'm still working on those reports.")Or send a new message to the channel of that message:
await message.channel.send("Working hard or hardly working?")Or do something only if the message matches a specific string:
if message.content == "I need you to work overtime":
await message.reply("I quit")
if message.content == "I've got pizza, how about some overtime?":
await message.reply("You don't pay me enough to eat so I'm forced to do overtime.")You can find a runnable example with all of this here.
You don't want to be hardcoding messages like above. You can use Python's strings to make it much more useful and flexible. You can take a quick look at an overview of Python strings here, and the full list of functions on strings here.
If you want to only act on messages that start with a specific string:
if message.content.startswith("$time"):
date_time_now = datetime.now()
await message.channel.send(date_time_now)If you want to only act on messages that contains a specific string:
if "burger king" in message.content:
await message.reply("Don't say that around me.")If you want to split a string into words (separated by spaces), and iterate through all of them:
splitMsg = message.content.split(' ')
for word in splitMsg:
print(f'{word}')You may also find array slicing useful for the last one. To only work on all but the first word, use splitMsg[1:], which translates to a new array, that contains all elements from 1:
splitMsg = message.content.split(' ')
for word in splitMsg[1:]:
print(f'{word}')There are many more things you can do with strings. A runnable example of the above can be found here.
- Always put
awaitbefore a discord API call. This is due to how the API works. - Have a separate file for your bot API so you don't accidentally share it. We have it in the source file here for simplicity.
- Python is full of APIs and is often referred to as a "glue language", so don't be afraid to use other APIs with your discord bot!
- Take a look at the developer portal again, and see how many more permissions the bot can have. Those are all things that the bot can have control over.
- Write a method that can reverse an input, for example "Something!" -> "!gnihtemoS"
- Write a function to count and output the total number of times a word has been said
- Write a function to sort a list of numbers
These challenges can take some time but are possible in most languages, including Java!
- Write a function to create commands dynamically
- For example "create test this is not a test" creates a command "test" which returns "this is not a test"
- Write a function to remove dynamic commands
- Write a function to encrypt an input like Enigma
- Write a function to decrypt the output back to the input
- Ideally these should not be cyclical (decrypting text and then encrypting it should not return the input)
- Use a third party API to pull weather data for a given location
- Have this command also output an image representing the weather conditions
- Reminder: Some cities share names with other cities in another country so don't forget to also take in a country or region, for example Swansea,US
- Now write a help function because you know you'll forget this nonsense!
We currently don't have any need for more bots but if you can think of something that may be useful, let one of us know. If you just want to build something that may be used by the society, we encourage you to try making something and to give your ideas a go!
Resources used and suggested