Fetches

Fetches is a simple extension to ActionController that allows you to DRY up your model fetching with a simple, intuitive syntax. Rather than creating helpers or manually finding records each time an action is processed, simply add a call to ‘fetches’ in your controller and it will take care of the rest.

Installation

Fetches is available as a gem as well as in traditional plugin format. To install as a gem, add this to your environment.rb:

config.gem 'mbleigh-fetches', :source => 'http://gems.github.com', :lib => "fetches"

To install it as a traditional plugin:

script/plugin install git://github.com/mbleigh/fetches.git

Example

class UsersController < ApplicationController
  fetches :user

  def show
    user # equivalent to a memoizing call to User.find(params[:id])
  end
end

It’s very simple, and can also be extended to meet more complex demands, such as:

# routes as a nested /users/:user_id/articles
class ArticlesController < ApplicationController
  fetches :user, :as => :author, :from => :user_id, :using => :find_by_login
  fetches :article

  def index
    author # equivalent to User.find_by_login(params[:user_id])
  end
end

You may also pass a Proc into the “from” option in order to fetch from a more complex set of requirements:

class UsersController < ApplicationController
  fetches :user, :from => Proc.new{ |c| c.params[:user_id] || c.params[:id] }
end

Finally, you can use the :initialize option to initialize a new record using parameters or Proc-based information:

fetches :user, :initialize => true
fetches :user, :initialize => :author # initialize from params[:author]
fetches :user, :initialize => Proc.new{ |c| {:login => params[:login], :email => params[:email]} }

The helper method generated memoizes (initializes once then doesn’t make additional calls to the database) and is available both in the controller and the view.