Question

Is there an easy way to test if the current directory is inside a rails project? Clearly Rails itself tests this in order to use the rails subcommands (generate, scaffold, etc.), so presumably there’s a straight-forward way to test this.

I’m looking for something similar to how you would test if you’re inside a Git repo.

Answer 1

Upon further investigation, I was able to dig into the rails command itself and based a solution on part of the railties gem (<railties>/lib/rails/script_rails_loader.rb):

#!/usr/bin/env ruby

require 'pathname'

SCRIPT_RAILS = File.join('script', 'rails')

def self.in_rails_application?
  File.exists?(SCRIPT_RAILS)
end

def self.in_rails_application_subdirectory?(path = Pathname.new(Dir.pwd))
  File.exists?(File.join(path, SCRIPT_RAILS)) || !path.root? && in_rails_application_subdirectory?(path.parent)
end

if in_rails_application? || in_rails_application_subdirectory?
  exit(0)
else
  exit(1)
end