How to build your own Twitter bot in less than 20 lines of code

How I used Ruby and Serverless to build a Twitter bot within 30 minutes

I used Zappa and Python previously to deploy and sell my API on RapidAPI. This made me think if I could do something with Serverless and Ruby so that I have hands-on experience with them. I was looking at some of the sample projects on the Serverless website when a Twitter bot written in node stood out.

Taking inspiration from the same, I decided to create a bot that would tweet haiku at a regular interval. Let’s get started

Step 1: Set up a Twitter application

Head to https://developer.twitter.com/en so that you can create an account and get access to Twitter APIs.

You want to choose bot and fill in the basic details

Twitter does ask a lot of questions and as long as you fill in reasonable answers, you will get through. Once you have filled the form, create an app, and head over to the Keys and tokens section. From there grab your API Key, Secret, Access token, and secret

You will need all 4

Step 2: Set up your code

You first need to install serverless and AWS. Assuming that you already have an AWS account, you will need to add the AWS key and secret to your local env. If you are interested in creating profiles, I have a small section about it in this post.
You can get started with serverless using the commands below

npm install serverless -g
serverless create -t aws-ruby -p twitter-haiku-bot

The AWS-ruby is a very basic template and you will need to modify the same a lot.

cd twitter-haiku-bot/

To get started, let's create a Gemfile in the project with the following Gems

source 'https://rubygems.org'
gem 'twitter'

After that, we can do a

bundle install

Now that we have the required gems, let's go ahead and create an environment config file for the dev called dev.env.json with the following details

{
  "TWITTER_CONSUMER_KEY": "<your twitter api key>",
  "TWITTER_CONSUMER_SECRET": "<your twitter api secret>",
  "TWITTER_ACCESS_TOKEN_KEY": "<your twitter access token>",
  "TWITTER_ACCESS_TOKEN_SECRET": "<your twitter access token secret>"
}

From there, lets now move on to the code

require 'json'
require 'twitter'

def bot(event:, context:)
 begin
  client = Twitter::REST::Client.new do |config|
   config.consumer_key        = ENV['TWITTER_CONSUMER_KEY']
   config.consumer_secret     = ENV['TWITTER_CONSUMER_SECRET']
   config.access_token        = ENV['TWITTER_ACCESS_TOKEN_KEY']
   config.access_token_secret = ENV['TWITTER_ACCESS_TOKEN_SECRET']
  end
  haiku = client.search('#haiku').first.text
  client.update(haiku) 
end

We now need to configure the serverless.yml file

service: twitter-haiku-bot
provider:
  name: aws
  runtime: ruby2.5

custom:
  env: ${file(./${self:provider.stage}.env.json)}

functions:
  bot:
    handler: handler.bot
    events:
      - schedule: rate(6 hours)
    environment:
      TWITTER_CONSUMER_KEY: ${self:custom.env.TWITTER_CONSUMER_KEY}
      TWITTER_CONSUMER_SECRET: ${self:custom.env.TWITTER_CONSUMER_SECRET}
      TWITTER_ACCESS_TOKEN_KEY: ${self:custom.env.TWITTER_ACCESS_TOKEN_KEY}
      TWITTER_ACCESS_TOKEN_SECRET: ${self:custom.env.TWITTER_ACCESS_TOKEN_SECRET}

The bot is now configured to run every 6 hours and post a Haiku on the account.

Step 3: Deploy

So let's deploy
sls deploy

This takes time and once it is deployed you can invoke the function using
sls invoke -f bot

If everything runs fine, you should see a Haiku posted on your account like this

Troubleshooting

If not, this is the most common error that you will see

For someone just starting out, this bug is annoying and there is a lot of discussion in the forums about how to solve it. However, after much trial and error, this is the solution that worked for me, serverless-ruby-package

npm install --save-dev serverless-ruby-package

In the serverless.yml file added the following

plugins:
  - serverless-ruby-package
package:
  include:
    - handler.rb
    - lib/**

Added the following lines on top of handler.rb file

# handler.rb
load "vendor/bundle/bundler/setup.rb"
$LOAD_PATH.unshift(File.expand_path("lib", __dir__))

Post this I just deployed the serverless function again
sls deploy

Now I have a bot that runs every 6 hours and posts a haiku if it finds it suitable. You can find and follow my bot here:
https://twitter.com/HaikuDaily3

So what bot are you creating today? Let me know in the comments and we can follow each other.