Sending Attachments

Attachments let you upload files directly to Discord. discord-luau supports sending them by providing the raw file content as a string.

Prerequisites

This guide uses the onMessage event, which requires the MessageContent intent. Make sure it is enabled in the Discord Developer Portal under your application’s Bot tab.

Adding an attachment to a message

Call :addAttachment(content, name) on a builders.message.message object, where content is the raw file data as a string and name is the filename that will appear in Discord.

local discord  = require("@self/../luau_packages/discord")
local classes  = require("@self/../luau_packages/classes")
local builders = require("@self/../luau_packages/builders")
local env      = require("@self/../.env")

local bot = discord.bot.new({
    token = env.DISCORD_BOT_TOKEN,
    intents = builders.intents.new({ "Guilds", "GuildMessages", "MessageContent" }):build(),
    reconnect = true,
})

bot.onMessage:listen(function(message: classes.Message)
    if message.content ~= "!file" then
        return
    end

    message:replyAsync(
        builders.message.message.new()
            :addAttachment("Hello from discord-luau!", "hello.txt")
            :build()
    ):await()
end)

bot.onAllShardsReady:listenOnce(function()
    print(`Bot '{bot.user.username}' is online!`)
end)

bot:connectAsync():await()

Multiple attachments

Call :addAttachment() multiple times to include more than one file in a single message. Each call adds one file.

message:replyAsync(
    builders.message.message.new()
        :addAttachment("First file contents", "first.txt")
        :addAttachment("Second file contents", "second.txt")
        :build()
):await()

Combining attachments with text or embeds

Attachments, message content, and embeds can all be combined on the same message builder.

message:replyAsync(
    builders.message.message.new()
        :setContent("Here is your file:")
        :addAttachment("some,csv,data\n1,2,3", "data.csv")
        :build()
):await()

File content is a string

The content argument to :addAttachment() is always a plain Luau string. For binary formats, you would need to encode the data as a string first.

Full script

local discord  = require("@self/../luau_packages/discord")
local classes  = require("@self/../luau_packages/classes")
local builders = require("@self/../luau_packages/builders")
local env      = require("@self/../.env")

local bot = discord.bot.new({
    token = env.DISCORD_BOT_TOKEN,
    intents = builders.intents.new({ "Guilds", "GuildMessages", "MessageContent" }):build(),
    reconnect = true,
})

bot.onMessage:listen(function(message: classes.Message)
    if message.content ~= "!file" then
        return
    end

    message:replyAsync(
        builders.message.message.new()
            :addAttachment("Hello from discord-luau!", "hello.txt")
            :build()
    ):await()
end)

bot.onAllShardsReady:listenOnce(function()
    print(`Bot '{bot.user.username}' is online!`)
end)

bot:connectAsync():await()

References

• Bot - the discord.bot class, gateway connection and event emitters
• Message builder - builders.message.message, constructs message payloads including attachments
• Message class - classes.Message, the object passed to onMessage handlers
• Intents builder - builders.intents, constructs the gateway intent bitfield
• Futures - the FutureLike async primitive returned by async calls