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

I'm tired of writing RESTful boilerplate (& scaffold is overkill), so I'm stoked natehop released the Coast gem.

-- Brandon Hayes, April 10, 2012

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hopsoft / coast

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