Auto-loading lib files in Rails 4

Question

I use the following line in an initializer to autoload code in my /lib directory during development:

config/initializers/custom.rb:

Answer 1

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 2

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

Answer 3

I think this may solve your problem:

1. 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
   

2. 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 4

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.