does_alice_follow_bob.rb

#!/usr/bin/env ruby

require "httparty"

BEARER_TOKEN = ENV["TWITTER_BEARER_TOKEN"]

abort "No TWITTER_BEARER_TOKEN in env" if BEARER_TOKEN.nil?
abort "Provide 2 usernames" if ARGV.size != 2

def get_user_by_username(username)
  api_call("/users/by", query: { usernames: username })["data"][0]
end

def follows?(follower, followed, pagination_token: nil)
  response = api_call(
      "/users/#{follower}/following",
      {pagination_token:, max_results: 1000}
  )

  if response["data"].include?(followed) return true end

  next_token = response["meta"]["next_token"]
  if next_token.nil? return false end

  follows?(follower, followed, next_token)
end

def api_call(path, query: {})
  response = HTTParty.get(
    "https://api.twitter.com/2#{path}",
    query:,
    headers: {"Authorization": "Bearer #{BEARER_TOKEN}"},
  )

  if response.code.to_s.start_with?("4", "5") || response["errors"]
    puts "API Error"
    pp response
    abort
  end

  response
end
	
follower, followed = ARGV.map { |username| get_user_by_username(username) }

if follows?(follower, followed)
  puts "y"
else
  puts "n"
  exit 1
end

def follows_iter?(follower, followed, pagination_token: nil)
  paginated_api("/users/#{follower}/following", |data| do
    if data.include?(followed) return true end
  end)

  false
end

def paginated_api(path, &block)
  token = nil
  while true
    response = api_call(path, {pagination_token: token, max_results: 1000})

    block(response["data"])

    token = response["meta"]["next_token"]
    if token.nil? return end
  end
end