Working With Rails

Http Caching

= http_caching plugin for Rails

Allows your Rails application to take advantage of the caching mechanisms built into HTTP 1.1 (i.e., 304 Not Modified return code). Inspired by a Rails cookbook entry (http://manuals.rubyonrails.com/read/chapter/62).

Installation

If your project is source-controlled by Subversion (which it should be, really), the easiest way to install this is via Rails' plugin script:

./script/plugin install -x http://svn.codahale.com/http_caching

If you're not using Subversion, or if you don't want it adding svn:externals in your project, remove the -x switch:

./script/plugin install http://svn.codahale.com/http_caching

Usage

An example using send_data:

def get_orders
  @photo = Photo.find(params[:id])
  if_cached_before @photo.updated_at do
    send_data @photo.data, :type => @photo.mime_type, :disposition => 'inline'
  end
end

Another example, this time using a simple RHTML view:

def get_user_profile
  @user = User.find(params[:id])
  render_if_cached_before @user.updated_at
end

A slightly more complicated RHTML example:

def get_orders
  render_if_cached_before Order.maximum(:updated_at), :layout => 'orders_feed', :action => 'all_orders'
end

Or you can keep frequent refreshers from swamping your server:

def shiny_object
  if_cached_before 10.minutes.ago do
    @shiny_object = ShinyObject.complicated_database_call(:woo => :hah)
  end
end

You get the idea.

Resources = Subversion

• http://svn.codahale.com/http_caching

=== Blog

• http://blog.codahale.com

== Credits

Written by Coda Hale <coda>. Released under the MIT License for great justice.

NOTE: This description has been extracted from the Plugin README and so the formatting may need updating to make browser friendly