DRY Controller Example

Readme.md

A DRY Controller Example

• DRY with respond_with and respond_to
• Use responder for i18n flash messages
• USe responder for expiration headers
• Default pagination
• Use has_scope for model scopes
• Custom record not found error
• CSV export

_not_found.html.erb

<!-- app/views/gizmos_not_found.html.erb -->
<h1> Gizmo not found </h1>
<p>Can't find Any Gismo with id <%= params[:id] %> </p>

<%= link_to 'Cheaper than 10', gizmos_path(:cheap  => 10) %>
<%= link_to 'recent', gizmos_path(:recent  => "1") %>
<%= link_to "All Gizmos", gizmos_path %>

Gemfile

gem 'responders'
gem 'has_scope'
gem 'kaminari'

# TODO: Find a better gem
gem 'csv_builder'

gizmo.rb

class Gizmo < ActiveRecord::Base
  scope :cheap, lambda {|price|
    where("price < ?", price)
  }
  scope :recent, lambda { |d|
    d ||= 2
    where("gizmos.created_at > ?", d.to_i.days.ago)
  }
end

gizmos_controller.rb

class GizmosController < ApplicationController

  has_scope :recent, :allow_blank => true
  has_scope :cheap,  :allow_blank => true do |contr, scope, value|
    value = (value || 100).to_i
    scope.cheap(value)
  end
  has_scope :page, default: 1, :only => :index, :unless => :csv_request?

  responders :flash, :http_cache
  respond_to :html, :json, :xml

  respond_to :csv, :only => :index

  rescue_from ActiveRecord::RecordNotFound, :with => :rescue_not_found

  def index
    @gizmos = apply_scopes(Gizmo).scoped
    @filename = 'gizmos.csv'
    @output_encoding = 'UTF-8'
    @csv_options = { :force_quotes => true, :col_sep => ',' }

    respond_with(@gizmos)
  end

  def show
    @gizmo = Gizmo.find(params[:id])
    respond_with(@gizmo)
  end

  def new
    @gizmo = Gizmo.new
    respond_with(@gizmo)
  end

  def edit
    @gizmo = Gizmo.find(params[:id])
  end

  def create
    @gizmo = Gizmo.new(params[:gizmo])
    @gizmo.save
    respond_with(@gizmo)
  end

  def update
    @gizmo = Gizmo.find(params[:id])
    @gizmo.update_attributes(params[:gizmo])
    respond_with(@gizmo)
  end

  def destroy
    @gizmo = Gizmo.find(params[:id])
    @gizmo.destroy
    respond_with(@gizmo)
  end

  protected
  def rescue_not_found
    render :partial => 'not_found', :status => :not_found
  end
  def csv_request?
    request.format.to_s.downcase == 'text/csv'
  end

end

index.csv.csvbuilder

csv << ["Name", "Price"]
@gizmos.each do |row|
  csv << [row.name, row.price]
end

index.html.erb

<%= link_to 'Cheaper than 10', gizmos_path(:cheap  => 10) %>
<%= link_to 'recent', gizmos_path(:recent  => "1") %>
<%= link_to "All Gizmos", gizmos_path %>
<%= link_to 'Gizmos AS CSV', gizmos_path(:format => :csv) %>