module ActionController::ConditionalGet::ClassMethods - actionpack-4.2.4 Documentation

# module ActionController::ConditionalGet::ClassMethods

### Public Instance Methods

etag(&etagger) click to toggle source

Allows you to consider additional controller-wide information when generating an ETag. For example, if you serve pages tailored depending on who's logged in at the moment, you may want to add the current user id to be part of the ETag to prevent authorized displaying of cached pages.

    class InvoicesController < ApplicationController
      etag { current_user.try :id }

      def show
        # Etag will differ even for the same invoice when it's viewed by a different current_user
        @invoice = Invoice.find(params[:id])
        fresh_when(@invoice)
      end
    end

    # File lib/action_controller/metal/conditional_get.rb, line 30
    def etag(&etagger)
      self.etaggers += [etagger]
    end