Coast
Resourceful behavior for Rails controllers
Simply include the Coast module in your controller and get these actions for free.
new
edit
index
show
create
update
destroy
But wait... there's more.
- Lightweight - about 200 lines of code... you can grok it in 5 minutes by skimming lib/coast.rb
- Unobtrusive - no monkey patches
- Flexible - support for html, xml, and json formats
- Familiar - simple DSL for hooking into action callbacks
- Secure - implicit authorization with your favorite libs... such as CanCanCan, Perm, et al.
Works best when you stick to Rails conventions
Quick-start for the lazy
Assume you have a simple app structure for beach bums.
app/controllers/beach_bums_controller.rb
app/models/beach_bum.rb
Install the GEM.
$gem install coast
Tweak some files.
# config/routes.rb
Beach::Application.routes.draw do
resources :beach_bums
end
# app/controllers/beach_bums_controller.rb
class BeachBumsController < ApplicationController
include Coast
end
Congratulations... you now have a RESTful API for beach bums.
Callbacks
Coast uses a Sinatra like DSL to provide hooks into the action lifecycle.
The following hooks are supported for each action.
-
before
- before any other action logic is performed... just like a Rails before_filter -
respond_to
- after authorization and db work but before rendering or redirecting -
after
- after all other action logic is performed... just like a Rails after_filter
How to use the callbacks
# app/controllers/beach_bums_controller.rb
class BeachBumsController < ApplicationController
include Coast
before :show do
# take control and load a 'beach_bum' instead of letting Coast do it for us
@resourceful_item = BeachBum.find(params[:id])
# Coast will implicitly create an @beach_bum variable that references @resourceful_item
# cool eh?
end
respond_to :show do
# take control of rendering or redirecting instead of letting Coast do it for us
render :text => "Out surfing."
end
after :show do
# do some last minute housekeeping after every thing else is done
Rails.logger.info "Hey brah... we just completed the show action."
end
end
Authorization
Coast implicitly calls an authorize method prior to executing any action logic.
You have complete control over this method. Here's an example.
# app/controllers/beach_bums_controller.rb
class BeachBumsController < ApplicationController
include Coast
set_authorize_method :authorize
def authorize(action, data, request)
# restrict all RESTful actions
raise "Unauthorized"
end
rescue_from Exception do |ex|
render :text => "Not Allowed", :status => 401
end
end
Note the authorize method signature. The first arg is the action being performed. The second arg is the record(s) being operated on. The last arg is the request object.
While originally written to support CanCan, its pretty simple to take control and manage authorization yourself.
Localization
Enable I18n internationalization with a simple method call.
# app/controllers/beach_bums_controller.rb
class BeachBumsController < ApplicationController
include Coast
set_localized true
end
Advanced Usage
Coast comes with few tricks up its sleeve.
If your model and controller names deviate from Rails conventions, you can explicitly set the model like so.
# app/controllers/beach_bums_controller.rb
class BeachBumsController < ApplicationController
include Coast
set_resourceful_model SurferDude
end
You can conditionally prevent mutating behavior on the server by setting an instance variable like so. It's a little arcane, but that's on purpose.
# app/controllers/beach_bums_controller.rb
class BeachBumsController < ApplicationController
include Coast
before :create do
# prevent the user from actually creating a record
@skip_db_create = true
end
before :update do
# prevent the user from actually saving a record
@skip_db_update = true
end
before :destroy do
# prevent the user from actually destroying a record
@skip_db_destroy = true
end
end
Praise
-- Brandon Hayes, April 10, 2012