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. # # You can also just pass a record where last_modified will be set by calling updated_at and the etag by passing the object itself. Example: # # def show # @article = Article.find(params[:id]) # fresh_when(@article) # end # # When passing a record, you can still set whether the public header: # # def show # @article = Article.find(params[:id]) # fresh_when(@article, :public => true) # end def fresh_when(record_or_options, additional_options = {}) if record_or_options.is_a? Hash options = record_or_options options.assert_valid_keys(:etag, :last_modified, :public) else record = record_or_options options = { :etag => record, :last_modified => record.try(:updated_at) }.merge(additional_options) end 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 # # You can also just pass a record where last_modified will be set by calling updated_at and the etag by passing the object itself. Example: # # def show # @article = Article.find(params[:id]) # # if stale?(@article) # @statistics = @article.really_expensive_call # respond_to do |format| # # all the supported formats # end # end # end # # When passing a record, you can still set whether the public header: # # def show # @article = Article.find(params[:id]) # # if stale?(@article, :public => true) # @statistics = @article.really_expensive_call # respond_to do |format| # # all the supported formats # end # end # end def stale?(record_or_options, additional_options = {}) fresh_when(record_or_options, additional_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, :public => true, :must_revalidate => true # # This method will overwrite an existing Cache-Control header. # See http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html for more possibilities. # # The method will also ensure a HTTP Date header for client compatibility. def expires_in(seconds, options = {}) #:doc: response.cache_control.merge!( :max_age => seconds, :public => options.delete(:public), :must_revalidate => options.delete(:must_revalidate) ) options.delete(:private) response.cache_control[:extras] = options.map {|k,v| "#{k}=#{v}"} response.date = Time.now unless response.date? 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