Autoloader

DRY up your controllers by autoloading the used models with AutoLoader. With Autoloader, you can get rid of those tedious and repetitive User.find(params[:id])-calls and enjoy the real programming of the controllers.

Installation

Add this line to your application's Gemfile:

gem 'autoloader', :git => 'https://bitbucket.org/musicspot/autoloader'

And then execute:

$ bundle install

Beta note

Autoloader is still in beta and not available on rubygems.org yet. We will publish it there as soon as it's a bit stable. Please don't use it in production yet and expect the API to change a tiny bit in the future.

Usage

The autoload_resource controller macro will automatically be added to all your controllers. It lets you define which model you want to load based on your own criteria.

The autoload_resource call lets you define a few options to customize its behaviour. You can use it as follows:

autoload_resource model, [options]

Options are

:identifier (Symbol) which param to use to find the record. Default: :id

    autoload_resource :user, :identifier => :member_id
    
:only (Symbol) on which controller actions the record should be loaded

    autoload_resource :user, :only => [:show, :index]
    
:except (Symbol) on which actions to skip loading

    autoload_resource :user, :except => :destroy
    
:scope (Proc) the scope in which to search the record. Default: Model class

    autoload_resource :user, :scope => Proc.new { User.administrators }
    # Produces User.administrators.find(#)

Example

That's some though stuff to understand. Here's an example to make it more clear:

class PostController < ApplicationController
  autoload_resource :post, :scope => { current_user.posts }, :except => :share 

  def index
    # @posts is available, can be used directly in view
  end

  def show
    # @post is available
    @comments = @post.comments
  end

  def create
    # @post is Post.new(params[:post])
    @post.save
  end
  
  def share
  	FacebookConnector.publish_all
  end
end

The above code tells autoloader to automatically load the Sample-model on all actions except for the share action. That means that the entire collection of posts is loaded for the index action, and one post for each of the other actions (show, new, create, edit, update, destroy). To see how the records are generated, read the How Records Are Loaded section.

How Records Are Loaded

Autoloader uses a different strategy to load the models for the different actions. Here is a list how they work, in this example with a call to autoload_resource :post:

• show: A single record is loaded with Post.find(:id) and available as @post
• index: All records in the defined scope are loaded with Post.all and available as @posts
• new: A new record is initalized with Post.new and available as @post
• create: A new record, initalized with the attributes in params[:post], but not yet saved, is available as @post
• edit: A single record, obtained with Post.find(:id) is available as @post
• update: A single record, updated with the attributes in params[:post], but not yet saved, is available as @post
• destroy: A single record, loaded with Post.find(:id) is available in @post
• Custom actions: if the id parameter is available, a single record is loaded (similar to the show action). Otherwise, all records are loaded (similar to the index action)

Multiple Loaders

If you really need to, you can define multiple loaders in a single controller. Consider an application with the Group and Contact models, which reference each other with a has_many relation. The controller could look as follows:

class GroupsController < ApplicationController
  autoload_resource :group
  autoload_resource :contact, :identifier => :contact_id, :only => [:add_contact, :remove_contact]

  def create
    current_user.groups << @group
    redirect_to contacts_path
  end

  def add_contact
    ContactBook.new.for(current_user).add_to_group(@contact, @group)
    redirect_to contacts_path
  end

  def remove_contact
    @group.contacts.delete @contact
    redirect_to contacts_path
  end

  def destroy
    @group.destroy
    redirect_to contacts_path
  end


  private

  def group_params
    params.required(:group).permit(:name)
  end
end

Help me!

If you need help, use either the issue tracker or Twitter (@LukasSkywalker).

Contributing

1. Fork it
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create new Pull Request