scab.rb

#!/usr/bin/env ruby
require 'gems'
require 'bundler/setup'
require 'json'
require 'rubygems'

# Find the current version of a gem you are using, then find the latest
# version of the gem and put in a reminder that theres been updates.
#
# gemnasium used to do this but then they got bought and that service is
# gone, I think it was bundled into github
#

# Given the name of a gem, release_versions will return all released
# version strings -- it exludes everything that isn't of the form
# of dot separated numbers, i.e. no betas or rc1s or that kind of thing
#
# Goes to the network -- Rubygems only -- so not useful for private
# gems, but ye should be in charge of those already.
#
def release_versions(name)
  Gems.versions(name).map { |r| r['number'] }.select { |v| v =~ /^\d+.\d+(.\d+)*$/ }
end

# Scab returns a hash of the latest major versions of the gems in the hash
# which looks like { "gemname" : [array of gemspecs]}
def scab(gemhash)
  # This needs a sorted array -- you get it from Gems.versions anyway
  # so no need to do any sorts here directly, waste of time.

  # Should probably be able to do filters too, but eh that's not important
  results = {}
  gemhash.keys.each do |name|
    top_versions = release_versions(name).inject([]) do |acc, i|
      if acc.empty? || i[0] != acc.last[0]
        acc << i
      else
        acc
      end
    end
    results[a] = { vs: top_versions, cv: gemhash[name].first.version }
  end
  results
end

if ARGV.count > 0
  # If list of gems on command line, discover versions of them, ignoring ones
  # that are not installed locally
  installed_gems = Gem::Specification.group_by(&:name)
  arg_gems = ARGV.select { |g| installed_gems.key?(g) }
  filtered_gems = installed_gems.select { |g| arg_gems.include?(g) }
  STDOUT.puts scab(filtered_gems).to_json
else
  # If no list of gems on command line, ask Bundler what's in use
  # according to the local Gemfile.lock
  STDOUT.puts scab(Bundler.load.specs.to_hash).to_json
end