---
title: yeah what is that
teaser: Review of singleton resource routes in Rails.
tags: web,rails
author: Jared Carroll
published_on: 2007-10-12
---

Now most of the Rails community is familiar with `map.resources` since it was
officially released in Rails 1.2.3.  But another method came with it that I've
never used or seen anyone use.  So I decided to investigate it.

Looking at the doc for `ActionController::Resources#resource` it says

> No default index, new, or create routes are created for the singleton resource
> controller.

OK, so it looks like I shouldn't be creating these things with <abbr
title="HyperText Markup Language">HTML</abbr> forms.  My first impression was
that #resource was for one-to-one associations but that doesn't seem to be the
case.

Some further reading says #resource only gives you #new and #edit named routes.

OK, so it looks like I can view and edit these things and not delete them.

Here's what I think they should be used for.

Say we have users in our system.  And users have some attributes that are
central (and are usually required) to a user:

* email
* password
* name

As well as several attributes that seem to be related to their profile (and are
usually optional):

* age
* date\_of\_birth
* bio

Now you could say we have 2 objects here:

* User
* Profile

And a `User` `has_one` `Profile`.  But lets keep it simple and instead put
everything in the users table.

A client is then going to ask can we have 2 separate pages for viewing/editing
our basic user information and our profile information?.

Our first implementation might look like this:

```ruby
class UsersController < ApplicationController

  def new
  end

  def create
  end

  def show
  end

  def edit
  end

  def update
  end

  def profile
  end

  def edit_profile
  end

end
```

Look at those 2 ugly actions:

* profile
* edit\_profile

Lets move them into a separate profiles controller so we can stay with the <abbr
title="Create Read Update Delete">CRUD</abbr> action naming convention.

```ruby
class ProfilesController < ApplicationController

  def show
  end

  def edit
  end

end
```

We don't need an #update action in our `ProfilesController` because the #edit
form will POST to `UsersController#update` because it is editing a `User`
anyway.

Here's our routes file:

In `config/routes.rb`:

```ruby
ActionController::Routing::Routes.draw do |map|

  map.resources :users do |user|
    user.resource :profile
  end

end
```

That #resource gives us:

    /users/1/profile
    /users/1/profile;edit

And some named routes:

    profile_path
    profile_url
    edit_profile_path
    edit_profile_url

Now we have actions whos names don't stray from the basic <abbr title="Create
Read Update Delete">CRUD</abbr> naming conventions and also get some free named
routes from Rails.

Has anyone else used #resource? And what for?