How to get list of controllers and actions in ruby on rails?

Question

In rails, I can get the name of the current controller via controller_name and the current action by calling action_name. I am looking for similar runtime reflection for fetching the following:

1. List of all controllers in the application.
2. List of all actions in a given controller.

For example, I a Product controller which has "add" and "edit" actions. Can I pull the names of these actions programmatically to show the user what operations are supported?

I have looked at a method that calls for use of ActionController::Routing::Routes.named_routes.routes.each but I could not get that to work. I got uninitialized constant ActionDispatch::Routing::Routes error when I used it.

If there is any good tutorial or document that can help me understand how rails reflection capabilities. I searched for it but I mostly got active record reflection related blogs. I am looking for something that lets me get information on controllers and actions/methods at run time.
Thanks,

Tabrez

Solution 1

The easiest way to get a list of controller classes is:

ApplicationController.descendants

However, as classes are loaded lazily, you will need to eager load all your classes before you do this. Keep in mind that this method will take time, and it will slow down your boot:

Rails.application.eager_load!

To get all the actions in a controller, use action_methods

PostsController.action_methods

This will return a Set containing a list of all of the methods in your controller that are "actions" (using the same logic Rails uses to decide whether a method is a valid action to route to).

Solution 2

PostsController.action_methods will return all actions of PostsController including inherited, it's not what I want, I found PostsController.instance_methods(false), which will return all instance methods of PostsController and not include inherited, exactly what I want.

Solution 3

I had a similar problem; in my case it was for writing controller tests. There are certain basic tests that I want to run on every action for certain controllers (e.g., return 401 if the user is not logged in). The problem with the action_methods solution is that it picks up all methods on the controller class, even if the method does not have a corresponding route in config/routes.rb.

Here's what I ended up doing:

def actions_for_controller(controller_path)
  route_defaults = Rails.application.routes.routes.map(&:defaults)
  route_defaults = route_defaults.select { |x| x[:controller] == controller_path }
  route_defaults.map { |x| x[:action] }.uniq
end

So if you wanted a list of actions for PostsController, you'd say:

actions_for_controller('posts')

And you would get:

['show', 'create', 'edit', 'destroy'] (or whatever)

If you wanted a list of all controllers, something like this should do it:

def controllers_list
  route_defaults = Rails.application.routes.routes.map(&:defaults)
  files = route_defaults.map { |x| "#{x[:controller]}_controller" }.uniq
  files -= ['_controller']
  files.map { |x| x.split('/').map(&:camelize).join('::').constantize }
end

Solution 4

We are cleaning out unused controllers and actions. So I wanted to create an exhaustive list to mark for deletion. Here's what I ended up doing

ApplicationController.descendants.each do |controller|
  puts controller.name
  controller.action_methods.each do |action|
    puts '  ' + action
  end
end

That provides a nice list with actions indented under controller names.

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