What is Resourceful?
A whirlwind tour of resourcefulness in Rails.
What is a Resource?
- A Resource is a thing, a noun, a specific source of information.
- You can have a collection of things, or pick out a specific thing.
- Furthermore, you can do things to things. This is where verbs come in.
The seven Rails verbs
Rails is an opinionated framework, they provide seven main verbs for working with resources.
- index
- show
- new
- create
- edit
- update
- destroy
These are a very specific set of verbs. Let’s find out where they came from.
Four main HTTP verbs:
- GET: Gets the resource
- POST: Creates a new resource
- PUT: Updates an existing resource
- DELETE: Destroys a resource
These verbs can either apply to one resource, or the entire collection of resources.
Verbs in relation to the individual
http://example.com/resources/1
- GET: Show the individual record.
- POST: Treat the record as a collection and create a new entry in it.
- PUT: Update or replace an existing record.
- DELETE: Destroy the individual record.
Verbs in relation to the collection
http://example.com/resources/
- GET: List all of the collection’s records.
- POST: Create a new record in the collection.
- PUT: Replace the entire collection with another collection.
- DELETE: Destroy the entire collection.
The most common verbs
Typically, when dealing with resources, you end up with five verb/subject combinations you use almost exclusively.
GET /books # show all of the books
POST /books # create a new book
GET /books/:id # show a specific book
PUT /books/:id # update a specific book
DELETE /books/:id # destroy a specific book
How the common verbs map to Rails
Since web browsers only GET, we end up with two of these routes by name in rails:
books GET /books # show all of the books
POST /books # create a new book
book GET /books/:id # show a specific book
PUT /books/:id # update a specific book
DELETE /books/:id # destroy a specific book
But that’s only five verbs. What are the other two?
Forms, forms, forms
It wouldn’t make sense for us to POST to create a new book or PUT to update a book without describing what data we would like the book to have.
This is where forms come in. We get two more verbs now, new and edit, describing the actions before create and update respectively.
These both should give us a form to let us describe what data we would like to send with the request.
books GET /books # show all of the books
POST /books # create a new book
new_book GET /books/new # form for a new book
edit_book GET /books/:id/edit # form for an existing book
book GET /books/:id # show a specific book
PUT /books/:id # update a specific book
DELETE /books/:id # destroy a specific book
A Rails Resource
In fact, this is the exact output for a new rails resource when you run rake routes.
todos GET /todos(.:format) {:controller=>"todos", :action=>"index"}
POST /todos(.:format) {:controller=>"todos", :action=>"create"}
new_todo GET /todos/new(.:format) {:controller=>"todos", :action=>"new"}
edit_todo GET /todos/:id/edit(.:format) {:controller=>"todos", :action=>"edit"}
todo GET /todos/:id(.:format) {:controller=>"todos", :action=>"show"}
PUT /todos/:id(.:format) {:controller=>"todos", :action=>"update"}
DELETE /todos/:id(.:format) {:controller=>"todos", :action=>"destroy"}
There are four verbs we can GET, and these end up being our pages.
The other three non-GET verbs are used by the server itself or by a non-browser client.
Why is being resourceful important?
- Being resourceful is all about following standards.
- If we can treat all resources the same way, it’s easy to start working with another one.
- Some RIA frameworks like ActiveResource and Backbone count on it.
Backbone.js
Backbone is a framework that allows you to easily work with Rails resources.
Backbone, however, does NOT easily let you work with anything else.
If the back-end’s API is anything different than the resourceful set of routes we described earlier, give up on Backbone now.