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Prefixed Commands

Before Discord added slash commands, all bots had prefixed commands. A user would type the bot's prefix followed by a word or phrase to invoke a command, such as ?help or !help. However, this prefixed commands system isn't native to Discord! Developers made use of an on_message event to check if the message began with a certain character, then invoke the command. Every time a message was sent, the bot would see the message and check for its "prefix"

The syntax becomes a little more complicated when you want to have multiple commands. There are several disadvantages to this system. This is where the commands extension comes in. ext.commands has various advantages, such as:

  • Simpler syntax
  • Easier to use
  • Easier to parse user input
  • Comes with built-in help commands
  • Comes with a built-in system for categorizing commands
Prefixed Commands with Events
import discord

client = discord.Client()

@client.event
async def on_message(message):
if message.content.startswith("!ping"):
await message.channel.send("Pong!")

elif message.content.startswith("!announce"):
if len(message.content.split(" ")) < 3:
await message.channel.send("You need to specify a title and a message. Correct usage: `!announce Hello Hello everyone!`")
return

msg = message.content.split(" ", 2)
title = msg[1]
content = msg[2]

await message.channel.send("**{}**\n{}".format(title, content))

elif message.content.startswith("!"):
await message.channel.send("Unknown command.")
BobDotCom06/27/2022
!ping
RobocordBot06/27/2022
Pong!
BobDotCom06/27/2022
!announce Hello Hello World!
RobocordBot06/27/2022
Hello
Hello World!
BobDotCom06/27/2022
!help
RobocordBot06/27/2022
Unknown Command.

Syntax

Before we check out the syntax, let's take a look at the bot classes.

discord.Client - Contains only events.

discord.Bot - Subclasses discord.Client, adds commands.

discord.ext.commands.Bot - Subclasses discord.Bot, adds prefixed commands, cogs, and more.

This means that discord.ext.commands.Bot has both slash commands and prefixed commands, as well as events, cogs and more.

Now let's look at the syntax.

A Simple Prefixed Bot
import discord
from discord.ext import commands # Import the commands extension
# discord.ext.commands are not the same as discord.commands!

bot = commands.Bot(command_prefix="!") # You can change the command prefix to whatever you want.

@bot.command() # This is the decorator we use to create a prefixed command.
async def ping(ctx): # This is the function we will use to create the command.
await ctx.send("Pong!") # This is the response the bot will send.


bot.run("token") # Run the bot with your token.
BobDotCom06/27/2022
!ping
RobocordBot06/27/2022
Pong!
BobDotCom06/27/2022
!help
RobocordBot06/27/2022
No Category:
!help Shows this message
!ping

Type !help command for more info on a command.
You can also type !help category for more info on a category.

tip

The help command is a built-in command and is enabled by default. You will learn more about it in the following guides.

Parameters

Prefixed commands can take parameters, just like slash commands. You can specify the parameters in the function itself.

Parameters Example 1
@bot.command()
async def echo(ctx, *, message):
await ctx.send(message)

ctx is the context of the message. * means that the parameter can be any number of words. message is the parameter. If you had not passed *, message would only have been one word.

For example, if a user had used !echo hello world, message would have been hello. Since we passed *, message is hello world, or the rest of the message.

We can pass multiple parameters too!

Parameters Example 2
@bot.command()
async def echo(ctx, channel:discord.TextChannel, title, *, message):
await channel.send("**{}**\n{}".format(title, message))

In the example above, channel is a parameter that is of type discord.TextChannel. When you specify the type of the parameter, Pycord will automatically try to convert the parameter to that type. That is why you can use channel.send directly without needing to convert it first.

We also have a new parameter, title. This does not have a type, so it will be a string. * means that the rest of the message belongs to the next parameter, in this case, message.

When a user types !echo #general Greetings! Hello World!, channel will be the text channel #general, title will be Greetings! and message will be Hello World!.

Let's take an example where the user passes !echo #general Holiday Greetings! Greetings to you all!. Here, the user wants the title to be "Holiday Greetings!" and the message to be "Greetings to you all!". However, since Pycord parses the message at whitespaces, the title will end up being "Holiday" and the message "Greetings! Greetings to you all!". The user can prevent this by typing !echo "Holiday Greetings!" Greetings to you all!.

Santa Claus06/27/2022
!echo #general Holiday Greetings! Greetings to you all!
ElfBot06/27/2022
Holiday
Greetings! Greetings to you all!
Mrs. Claus06/27/2022
!echo #general "Holiday Greetings!" Greetings to you all!
ElfBot06/27/2022
Holiday Greetings!
Greetings to you all!

Let's check out another example for parameters and parameter types.

Parameters Example 3
import random

@bot.command()
async def gtn(ctx, guess:int):
number = random.randint(1, 10)
if guess == number:
await ctx.send("You guessed it!)
else:
await ctx.send("Nope! Better luck next time :)")

If you had not specified the type of the parameter, it would have been a string. And since "5" is not the same as 5 in python, the bot would have responded with "Nope! Better luck next time :)". Even if you do not specify the type of the parameter, you can still convert it later on, in this case, with int(guess).