Optional belongs_to and Rails routing

Question

I'm working on a Rails 3 task demo project in which each instance of Project has many tasks, and instances of Task belong to one project. However, this latter relationship is optional, although it's defined in the Task model as belongs_to :project.

Essentially, I want to be able to have routes like the following:

example.com/tasks/1
example.com/tasks/new

example.com/project/1/tasks/1
example.com/project/1/tasks/new

I'm not sure if this is possible or even good practice. Really what's most important is for me to be able to create project-less tasks from within the general tasks#index action, and tasks belonging to a project from within the project#show action via links to new actions.

I've read Rails Routing from the Outside In, but it didn't really explain what I'm going for.

Any help would be greatly appreciated.

Answer 1

This is actually more common than you think. Here is a solution:

class TasksController < ApplicationController
before_filter :get_project
before_filter :get_tasks


  private

  def get_project
    @project = Project.find(params[:project_id]) if params[:project_id]
  end

  def get_tasks
    @tasks = (@project) ? @project.tasks : Task
  end

end

From there you, you would always reference @tasks when you want to get the tasks.

So for an example:

def new
  @tasks.new(params[:task])
end

Would yield correct results whether you are nested or not.

In the case of nested, it would be like calling:

@projects.tasks.new(params[:task])

and without nested, it would be like calling:

Task.new(params[:task])