Use your own classes in the lib directory with Rails6

How to create and use your own class, This time, I will introduce how to make it under root / lib.


rails 6.0.3

application.rb settings


module Myapp
  class Application < Rails::Application
    config.load_defaults 6.0
    config.paths.add 'lib', eager_load: true #Add this

Add under lib to autoload_paths. About autoload_paths here

Configuration under lib

 ├── assets
 ├── asks
 └── utils
     └── hoge.rb

I have created utils / hoge.rb. Let's give it a descriptive name.

Contents of hoge.rb


class Utils::Hoge



module Utils
  class Hoge
     def greeting

Let's define a class with the name of the parent directory as the namespace. By doing this, you can hijack the rules of autoload_paths and call it as follows.


class ApplicationController < ActionController::Base
   hoge =
   #=> hello  


While writing this article, I found the following post. (The lack of research was revealed ...)

Fixed autoload_paths to eliminate mystery error

According to Rails Guaid "Before Rails 5, it was common to include lib / and below in autoload_paths, but now it is not recommended to put the code in a location other than the app folder and make it an autoload target." It is said that an error specific to the production environment may occur.

Since the app is included in autoload_paths by default, It seems good to use that.

So why does the lib directory exist? I wonder if people who are good at development use it properly.

That's all for this time, when new questions have arisen. Dedicated every day

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