Ruby on Rails 3 - Reload lib directory for each re

Question

I'm creating a new engine for a rails 3 application. As you can guess, this engine is in the lib directory of my application.

However, i have some problems developing it. Indeed, I need to restart my server each time I change something in the engine.

Is there a way to avoid this ?

Can I force rails to completely reload the lib directory or a specific file and his requirements for each request ?

Thanks for your help :)

Answer 1

TL;DR

• put this in config/application.rb

  config.eager_load_paths += ["#{Rails.root}/lib"]

• remove require statements for your lib files

Go!

---

Let me explain in detail.

I don't know why this answer is accepted, since it doesn't help with reloading lib folder on each request. First I thought that it works for Rails 2, but the question clearly states that it was for Rails 3 and the release date of 3.0.0 is before the date of the answer.

Other answers seem over-complicated or don't provide a real solution.

I decided to investigate things a little, because it was bothering me and I've even found out that people have a workaround for this and it involves saving lib files inside app/models in development and then moving it to /lib when done. We can do better, right?

---

My solution is tested against:

• Rails 3.0.20
• Rails 3.1.12
• Rails 3.2.13
• Rails 4.0.0.rc1

Put this into your config/application.rb:

# in config/application.rb
config.eager_load_paths += ["#{Rails.root}/lib"]

That's it!™

Make sure you put it here since it will not work if you put it in config/environments/development.rb, for example.

Make sure your remove all the require statements for your /lib code since require statements will also cause this solution to not work.

---

This code implicitly requires your code, so if you do environment checks (which are unnecessary) and instead of the above code, you decide to write something like this:

# in config/application.rb
config.eager_load_paths += ["#{Rails.root}/lib"] if Rails.env.development?

you should watch out on the old require statements, since they are still required on all the non-development environments, in this scenario.

So if you still decide to do environment checks, make sure you do inverse checks for require statements. Otherwise you'll get bitten!

require "beer_creator" unless Rails.env.development?

You might think that writing entire paragraph about something that's unnecessary is also unnecessary, but I think that warning people about something that's necessary when doing something unnecessary is also necessary.

If you would like to know more about this topic, check out this little tutorial.

Answer 2

You have to add

config.autoload_paths += %W(#{config.root}/lib)

to your Application class in config/application.rb

https://rails.lighthouseapp.com/projects/8994/tickets/5218-rails-3-rc-does-not-autoload-from-lib

Answer 3

Also, make sure that you comment out the following line in application.rb (in addition to @dishod's solution), and make sure that your module name is the same as your file name (otherwise, rails won't be able to find it)

#Dir.glob("./lib/*.{rb}").each { |file| require file } # require each file from lib directory

Answer 4

Since we are talking Rails, the easiest way is to 'require' your lib/* .rb files using 'require_dependency'. So long as the controller/helper/etc (.rb files under app/) uses require_dependency instead of just require reloading works, without the need to do anything funky.

Before I went down that track, the only solution that worked was the one on hemju.com, but I really did not want to have to hack the ApplicationController for Dev speed.

Answer 5

Add to application_controller.rb or your base controller:

  before_filter :dev_reload if Rails.env.eql? 'development'

  def dev_reload
    # add lib files here
    ["rest_client.rb"].each do |lib_file|
      ActiveSupport::Dependencies.load_file lib_file
    end
  end

Worked for me.

Answer 6

note that in Rails 3 "load_once_paths" becomes "autoload_once_paths."

Also, it appears that it should be empty unless you explicitly put something in it.