How do you check the Gem Version in Ruby at Runtime?

问题

Is it possible to check the gem version of the currently loaded gem in a ruby/rails app?

During debugging, I would like to be able to do something like:

puts RubyGem.loaded_version(:active_support)

Anything like that exist?

回答1:

puts Gem.loaded_specs["activesupport"].version

回答2:

careful when comparing against Gem.loaded_specs['mini_magick'].version as it's not a String but a Gem::Version object !

the version string is accessible using Gem.loaded_specs['mini_magick'].version.version which is ugly and might not work as expected e.g. '2.2' > '2.10' !

the correct way to compare against a gem version is :

Gem.loaded_specs['mini_magick'].version < Gem::Version.create('2.0')

来源：https://stackoverflow.com/questions/2954279/how-do-you-check-the-gem-version-in-ruby-at-runtime