Skip to content
Rails 3 Version of render_component
Find file
Pull request Compare This branch is 40 commits ahead of rails:master.
Latest commit aeec387 @vhochstein bump version


Components allow you to call other actions for their rendered response while executing another action. You can either delegate
the entire response rendering or you can mix a partial response in with your other content.

  class WeblogController < ActionController::Base
    # Performs a method and then lets hello_world output its render
    def delegate_action
      render_component :controller => "greeter",  :action => "hello_world", :params => { :person => "david" }

  class GreeterController < ActionController::Base
    def hello_world
      render :text => "#{params[:person]} says, Hello World!"

The same can be done in a view to do a partial rendering:

  Let's see a greeting:
  <%= render_component :controller => "greeter", :action => "hello_world" %>

It is also possible to specify the controller as a class constant, bypassing the inflector
code to compute the controller class at runtime:

<%= render_component :controller => GreeterController, :action => "hello_world" %>

== When to use components

Components should be used with care. They're significantly slower than simply splitting reusable parts into partials and
conceptually more complicated. Don't use components as a way of separating concerns inside a single application. Instead,
reserve components to those rare cases where you truly have reusable view and controller elements that can be employed
across many applications at once.

So to repeat: Components are a special-purpose approach that can often be replaced with better use of partials and filters.

Copyright (c) 2007 David Heinemeier Hansson, released under the MIT license
Something went wrong with that request. Please try again.