check whether a certain project name is available as a gem or npm package

chk

#!/usr/bin/env ruby

require 'httpclient'
require 'json'

class Chk

  RUBYGEMS_URL = 'http://rubygems.org/gems/%s'
  NPM_URL      = 'https://npmjs.org/package/%s'

  HTTPError = Class.new(StandardError)

  def initialize(client)
    @client = client
  end

  attr_reader :client

  def rubygems(name)
    puts "#{name} (rubygems): #{availability(name, RUBYGEMS_URL)}"
  end

  def npm(name)
    puts "#{name} (npm): #{availability(name, NPM_URL)}"
  end

  private

  def availability(name, url)
    available?(name, url) ? 'available!' : 'taken'
  end

  def available?(name, url)
    response = client.get(url % name)

    case response.status
      when 404 then true
      when 200 then false
      else          raise HTTPError, 'something went wrong!'
    end
  end

end


if ARGV.any?
  names = ARGV
else
  puts 'feed me possible project name(s)!'
  exit
end

client = HTTPClient.new
chk = Chk.new(client)

names.each do |name|
  chk.rubygems(name)
  chk.npm(name)
end

$ chmod +x chk
$ chk sinatra rails fancy-rainbows