How to autoload files in folder under rails app's root

Question

I am trying to have files under myapplication/somefolder. Google and Stackoverflow say I should add this:

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

in my config/application.rb, so I did.

But the files don't get loaded.

I tried namig somefolder/myclass.rb both class Myclass and class Somefolder::Myclass but still no luck.

I can see that the dir was found in Rails.application.config.autoload_paths in console does indeed include my /path/to/myapplication/somefolder directory, so that should be okay.

All the other questions around this topic use theapp/app/somefolder or theapp/lib/somefolder but not theapp/somefolder so maybe thats where it gets rotten.

So I tried referencing the class with ::Somefolder::MyClass but not even that helped.

I am using Rails 3.2.1

More research shows that `ActiveSupport::Dependencies.autoload_paths` didn't contain my `somefolder` path at runtime. Any ideas why? — hakunin, Feb 24 '12 at 11:56

score 2 · Accepted Answer · answered Aug 28 '13 at 23:53

Just ran into this myself today and decided to dive deep.

The reason you don't see in ActiveSupport::Dependencies.autoload_paths the paths you're adding to config.autoload_paths in config/application.rb is that they aren't copied over until the application is initialized. See rails/engine.rb in the railties gem:

module Rails
  class Engine < Railtie
    …

    # Set the paths from which Rails will automatically load source files,
    # and the load_once paths.
    #
    # This needs to be an initializer, since it needs to run once
    # per engine and get the engine as a block parameter
    initializer :set_autoload_paths, :before => :bootstrap_hook do |app|
      ActiveSupport::Dependencies.autoload_paths.unshift(*_all_autoload_paths)
      ActiveSupport::Dependencies.autoload_once_paths.unshift(*_all_autoload_once_paths)

      # Freeze so future modifications will fail rather than do nothing mysteriously
      config.autoload_paths.freeze
      config.eager_load_paths.freeze
      config.autoload_once_paths.freeze
    end

    …

    def _all_autoload_paths
      @_all_autoload_paths ||= (config.autoload_paths + config.eager_load_paths + config.autoload_once_paths).uniq
    end

    …
  end
end

Were you by any chance trying to invoke MyClass from within config/application.rb or, even earlier, from a script or module that requires config/application.rb? If so, you'll have to explicitly require the file defining MyClass, e.g.:

require File.expand_path('../../somefolder/my_class',  __FILE__)
# now use MyClass

score 1 · Answer 2 · answered Sep 14 '12 at 14:02

1

You should name somefolder/my_class.rb in order to autoload MyClass. You also should keep that config.autoload_paths += %W(#{config.root}/somefolder) line in your config/application.rb.

answered Sep 14 '12 at 14:02

gustavotkg

4,099
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score 1 · Answer 3 · answered Feb 24 '12 at 13:19

1

The workaround is to go to ActiveSupport::Dependencies.autoload_paths directly.

ActiveSupport::Dependencies.autoload_paths << "#{config.root}/somefolder"

But I am still looking for the reason why config.autoload_paths didn't work so if you post an aswer to that, I'll accept it!

answered Feb 24 '12 at 13:19

hakunin

4,041
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I have a same problem too :(. I'm using Rails 3.2.3. – Zeck May 15 '12 at 12:27

How to autoload files in folder under rails app's root

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