Read user's github gists

gists_checker.rb

require 'net/http'
require 'json'
require 'set'

# Method to return the content of the local db as a set
def read_db(file_db)
  unless File.exists?(file_db)
    return nil
  end
  read_gists = Set.new
  file = File.new(file_db, 'r')
  while (line = file.gets)
    read_gists.add(line.strip)
  end
  file.close
  return read_gists
end
# Method to create or update the local db
def update_db(file_db, gists_set)
  File.open(file_db, "w") do |f|
    f.write(gists_set.to_a.join("\n"))
  end
end

# Do a basic input validation
if ARGV[0] =~ /^[A-Za-z0-9-]+$/
  user = ARGV[0]
else
  puts "Usage: ruby #{$0} GITHUB_USERNAME"
  puts "Where GITHUB_USENAME may only contain alphanumeric characters or single hyphens"
  exit 2
end

GISTS_DB = "#{user}_gists.txt"
uri = URI("https://api.github.com/users/#{user}/gists")

# TO-DO error handling and retries
content = Net::HTTP.get(uri)
gists = JSON.parse(content)

current_gists = Set.new
gists.each do |gist|
  current_gists.add(gist['id'])
end

previous_gists = read_db(GISTS_DB)
# Enter here only if the database is not yet created
unless previous_gists
  update_db(GISTS_DB, current_gists)
  # First execution, returning 'changes' exit code
  exit 1
end

if current_gists == previous_gists
  # No gist changes, returning 'no changes' without updating GISTS_DB
  exit 0
else
  update_db(GISTS_DB, current_gists)
  # Found gist changes, returning 'changes' exit code
  exit 1
end

test commend