get_discord_guilds_for_user.rb

# Make sure you have a .env file with DISCORD_CLIENT_ID set

require "dotenv/load"
require "http"

puts "Go to the following URL in your browser to authorize this application:"
puts "https://discord.com/api/oauth2/authorize?response_type=token&client_id=#{ENV.fetch("DISCORD_CLIENT_ID")}&scope=identify%20email%20connections%20guilds%20guilds.join%20guilds.members.read%20messages.read"
puts ""
puts "Paste the URL you were redirected to after authorization:"

output = gets.strip
puts ""

ENV["ACCESS_TOKEN"] = URI.parse(output).fragment.split("&")[1].split("=").last

BASE_URI = "https://discord.com/api/v9"

def get(end_point)
  headers = {
    "User-Agent" => "DiscordBot (https://google.com, 1)",
    "Authorization" => "Bearer #{ENV.fetch("ACCESS_TOKEN")}"
  }
  uri = "#{BASE_URI}#{end_point}"
  request = HTTP.headers(headers).get(uri)
  JSON.parse(request.body.to_s)
end

guilds = get("/users/@me/guilds")

guilds.each do |guild|
  puts guild["name"]
end