# Extending Alchemy
At some point you may come across the need of adding some behavior to already existing controllers or models, that Alchemy provides. Obviously you could just copy the files, insert them into your projects and edit them there, but this isn't a really clean solution.
- This section will give you a hint on how to extend existing Alchemy files without overriding everything.
# Tell Rails to load our extensions
Tell Rails to load our extensions by adding some lines into
# config/application.rb config.to_prepare do Dir.glob(Rails.root.join('app', '**', '*_extension.rb')) do |f| Rails.configuration.cache_classes ? require(f) : load(f) end end
# Adding an extension
After you set up the loading for our extensions, we can actually start making some. Lets assume you want to add a before_action method to the
Alchemy::PagesController. You go into your host app and add a file in
pages_controller_extension.rb. It's important to add the
_extension to the filename so Rails will load them.
Into this file you add the following code:
module AlchemyPagesControllerExtension end Alchemy::PagesController.prepend AlchemyPagesControllerExtension
Into this block you can add anything you want your controller to do. As already mentioned, we want to add a before_action to this controller for some show off. It could then look like this:
module AlchemyPagesControllerExtension def prepended(base) base.before_action :some_method, only: :show end end
The last step is adding some_method to your
ApplicationController. This is done like you are used to in Rails.