Auto-loading lib files in Rails 4 - ruby-on-rails

Question

I use the following line in an initializer to autoload code in my /lib directory during development:
config/initializers/custom.rb:
RELOAD_LIBS = Dir[Rails.root + 'lib/**/*.rb'] if Rails.env.development?
(from Rails 3 Quicktip: Auto reload lib folders in development mode)
It works great, but it's too inefficient to use in production- Instead of loading libs on each request, I just want to load them on start up. The same blog has another article describing how to do this:
config/application.rb:
# Custom directories with classes and modules you want to be autoloadable.
config.autoload_paths += %W(#{config.root}/lib)
config.autoload_paths += Dir["#{config.root}/lib/**/"]
However, when I switch to that, even in development, I get NoMethodErrors when trying to use the lib functions.
Example of one of my lib files:
lib/extensions.rb:
Time.class_eval do
def self.milli_stamp
Time.now.strftime('%Y%m%d%H%M%S%L').to_i
end
end
Calling Time.milli_stamp will throw NoMethodError
I realize others have answered similar questions on SO but they all seem to deal with naming conventions and other issues that I didn't to have to worry about before- My lib classes already worked for per-request loading, I just want to change it to per-startup loading. What's the right way to do this?

Answer 1

I think this may solve your problem:
in config/application.rb:
config.autoload_paths << Rails.root.join('lib')
and keep the right naming convention in lib.
in lib/foo.rb:
class Foo
end
in lib/foo/bar.rb:
class Foo::Bar
end
if you really wanna do some monkey patches in file like lib/extensions.rb, you may manually require it:
in config/initializers/require.rb:
require "#{Rails.root}/lib/extensions"
P.S.
Rails 3 Autoload Modules/Classes by Bill Harding.
And to understand what does Rails exactly do about auto-loading?
read Rails autoloading — how it works, and when it doesn't by Simon Coffey.

Answer 2

Though this does not directly answer the question, but I think it is a good alternative to avoid the question altogether.
To avoid all the autoload_paths or eager_load_paths hassle, create a "lib" or a "misc" directory under "app" directory. Place codes as you would normally do in there, and Rails will load files just like how it will load (and reload) model files.

Answer 3

This might help someone like me that finds this answer when searching for solutions to how Rails handles the class loading ... I found that I had to define a module whose name matched my filename appropriately, rather than just defining a class:
In file lib/development_mail_interceptor.rb (Yes, I'm using code from a Railscast :))
module DevelopmentMailInterceptor
class DevelopmentMailInterceptor
def self.delivering_email(message)
message.subject = "intercepted for: #{message.to} #{message.subject}"
message.to = "myemail#mydomain.org"
end
end
end
works, but it doesn't load if I hadn't put the class inside a module.

Answer 4

Use config.to_prepare to load you monkey patches/extensions for every request in development mode.
config.to_prepare do |action_dispatcher|
# More importantly, will run upon every request in development, but only once (during boot-up) in production and test.
Rails.logger.info "\n--- Loading extensions for #{self.class} "
Dir.glob("#{Rails.root}/lib/extensions/**/*.rb").sort.each do |entry|
Rails.logger.info "Loading extension(s): #{entry}"
require_dependency "#{entry}"
end
Rails.logger.info "--- Loaded extensions for #{self.class}\n"
end