dependencies.rb

# Copyright 2009 Damian Janowski. MIT License.
# http://gist.github.com/100655
#
# Very simple script to handle Gem dependencies.
# It supports a basic vendoring system
# (just gem unpack to ./vendor)
#
# List your dependencies below and require this
# file at the very top of your program (think
# of it as a replacement for your require "rubygems").
#
# Also try:
#
#   $ ruby dependencies.rb
#
# to get a list of the required gems and to see
# which of them are vendored.

require 'rubygems'

RACK_ENV = ENV['RACK_ENV'] || 'development' unless defined? RACK_ENV

dependencies = <<-EOS
# Things you should know about version requirements:
# http://rubygems.org/read/chapter/16
#
# List your dependencies here.
#
# rack ~> 0.9
# haml ~> 2.0
# hpricot 0.8 (test)
# ruby-debug (development, test)
EOS

missing = []

dependencies.each_line do |line|
  next unless line =~ /^([\w\-_]+) ?([<~=> \d\.]+)?( \(([\w,]+)\))?$/

  name, version, env = $1, $2, $4

  next if env && !env.split(/\, ?/).include?(RACK_ENV.to_s)

  version = nil if version.empty?

  vendor_name = name.dup
  vendor_name << "-#{version[/([\d\.]+)$/, 1]}" if version
  vendor_path = File.join(File.dirname(__FILE__), 'vendor', "#{vendor_name}*", 'lib')

  if vendor_path = Dir[vendor_path].first
    # Vendored gem
    $:.unshift(vendor_path)
  else
    # RubyGems
    begin
      gem(*[name, version].compact)
    rescue Gem::LoadError => e
      $stderr.puts "=> #{e.message}"
      missing << [name, version]
    end
  end

  if $0 == __FILE__
    puts [name, version, ("(in #{vendor_path})" if vendor_path)].compact.join(" ")
  end
end

if missing.any?
  $stderr.puts if $0 == __FILE__

  missing.each do |spec|
    $stderr.puts "sudo gem install #{spec[0]} #{('-v %s ' % spec[1][/([0-9\.]+)$/] if spec[1])}--no-rdoc --no-ri"
  end
end