Ruby on Rails - Duplicate routes & impact on controllers

I am creating a Task Manager.

So, I have:

1. A dashboard where I can do CRUD for tasks (and then I will assign them a group)
2. A group section where I can go inside a group and do CRUD for tasks

Then my routes would look something like this:

Rails.application.routes.draw do
  devise_for :users
  namespace :api, defaults: { format: :json } do
    namespace :v1 do
      resources :groups, only: [ :index, :show, :create, :update, :destroy] do
        member do
          resources :tasks, only: [:index, :show, :create, :update, :destroy]
        end
      end
      resources :tasks, only: [:index, :show, :create, :update, :destroy]
    end
  end
end

For this:

1. A dashboard where I can do CRUD for tasks (and then I will assign them a group)

resources :tasks, only: [:index, :show, :create, :update, :destroy]

And for this:

2. A group section where I can go inside a group and do CRUD for tasks

resources :groups, only: [ :index, :show, :create, :update, :destroy] do
  member do
    resources :tasks, only: [:index, :show, :create, :update, :destroy]
  end
end

But I feel this is duplicating routes. I have 2 questions:

1. Is this the right approach or would there be a better way to solve it?
2. If I go with this, how would I approach the controller actions? Since in one situation (2) we would get the params[:group_id] but in the other I would need to add it as strong_params. Would an if-else condition work? (if there is no [:group_id] in strong_params then take the params[:group_id])

Thanks!

> Is this the right approach or would there be a better way to solve it?

No. Not really.

Deeply nested routes quickly become cumbersome to work with so you should consider using shallow nesting. This only nests the collection routes (index, new, create) and not the member routes (show, edit, update, destroy).

If tasks have a unique id you should be able to show, edit, update and destroy them without the group being involved. The exception to this rule is if tasks are only unique per group (but why?).

In an API this is especially true. The backend shouldn't need to know that you're modifying the resource from page X or Y in your frontend application.

You can use the shallow: true option to generate shallow routes but I would probally just define it as:

# This respresents tasks not nested in a group
resources :tasks, only: [:index, :show, :create, :update, :destroy]
 
resources :groups, only: [:index, :show, :create, :update, :destroy] do
  resources :tasks, only: [:index, :create]
end

> If I go with this, how would I approach the controller actions?

There are really two different approaches here. One I call the "param sniffing method":

module API
  module V1
    class TasksController
      # GET /api/v1/groups/1/tasks
      # GET /api/v1/tasks
      def index
        if params[:group_id]
          render json: Group.find(params[:group_id]).tasks
        else
          render json: Task.all
        end
      end
    end
  end
end

This is the most obvious solution but blatantly violates the Single Responsibity Principle and increases the cyclic complexity of all the methods.

The other solution is to route the nested representation of the resource to a separate controller:

# This respresents tasks not nested in a group
resources :tasks, only: [:index, :show, :create, :update, :destroy]
 
resources :groups, only: [ :index, :show, :create, :update, :destroy] do
  resources :tasks, only: [:index, :create], module: :groups
end

This routes the /groups/:group_id/tasks routes into API::V1::Groups::TasksController.

module API
  module V1
    class TasksController
      # GET /api/v1/tasks
      def index
        render json: Task.all
      end
    end
  end
end

module API
  module V1
    module Groups
      class TasksController
        before_action :set_group
 
        # GET /api/v1/groups/1/tasks
        def index
          render json: @group.tasks
        end

        private

        def set_group
          @group = Group.find(params[:group_id])
        end 
      end
    end
  end
end

You could also just do resources :tasks, only: [:index, :create], controller: :group_tasks if you want to avoid nesting the contants one more step.