module ActionController module ConditionalGet extend ActiveSupport::Concern include RackDelegation include Head # Sets the etag, last_modified, or both on the response and renders a # 304 Not Modified response if the request is already fresh. # # Parameters: # * :etag # * :last_modified # * :public By default the Cache-Control header is private, set this to true if you want your application to be cachable by other devices (proxy caches). # # Example: # # def show # @article = Article.find(params[:id]) # fresh_when(:etag => @article, :last_modified => @article.created_at, :public => true) # end # # This will render the show template if the request isn't sending a matching etag or # If-Modified-Since header and just a 304 Not Modified response if there's a match. # def fresh_when(options) options.assert_valid_keys(:etag, :last_modified, :public) response.etag = options[:etag] if options[:etag] response.last_modified = options[:last_modified] if options[:last_modified] response.cache_control[:public] = true if options[:public] head :not_modified if request.fresh?(response) end # Sets the etag and/or last_modified on the response and checks it against # the client request. If the request doesn't match the options provided, the # request is considered stale and should be generated from scratch. Otherwise, # it's fresh and we don't need to generate anything and a reply of 304 Not Modified is sent. # # Parameters: # * :etag # * :last_modified # * :public By default the Cache-Control header is private, set this to true if you want your application to be cachable by other devices (proxy caches). # # Example: # # def show # @article = Article.find(params[:id]) # # if stale?(:etag => @article, :last_modified => @article.created_at) # @statistics = @article.really_expensive_call # respond_to do |format| # # all the supported formats # end # end # end def stale?(options) fresh_when(options) !request.fresh?(response) end # Sets a HTTP 1.1 Cache-Control header. Defaults to issuing a private instruction, so that # intermediate caches must not cache the response. # # Examples: # expires_in 20.minutes # expires_in 3.hours, :public => true # expires_in 3.hours, 'max-stale' => 5.hours, :public => true # # This method will overwrite an existing Cache-Control header. # See http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html for more possibilities. def expires_in(seconds, options = {}) #:doc: response.cache_control.merge!(:max_age => seconds, :public => options.delete(:public)) options.delete(:private) response.cache_control[:extras] = options.map {|k,v| "#{k}=#{v}"} end # Sets a HTTP 1.1 Cache-Control header of no-cache so no caching should occur by the browser or # intermediate caches (like caching proxy servers). def expires_now #:doc: response.cache_control.replace(:no_cache => true) end end end