module ActionController module ConditionalGet extend ActiveSupport::Concern include RackConvenience # 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.utc, :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] if options[:public] response.cache_control[:public] = true end if request.fresh?(response) head :not_modified end end # Return a response that has no content (merely headers). The options # argument is interpreted to be a hash of header names and values. # This allows you to easily return a response that consists only of # significant headers: # # head :created, :location => person_path(@person) # # It can also be used to return exceptional conditions: # # return head(:method_not_allowed) unless request.post? # return head(:bad_request) unless valid_request? # render def head(*args) if args.length > 2 raise ArgumentError, "too many arguments to head" elsif args.empty? raise ArgumentError, "too few arguments to head" end options = args.extract_options! status = args.shift || options.delete(:status) || :ok location = options.delete(:location) options.each do |key, value| headers[key.to_s.dasherize.split(/-/).map { |v| v.capitalize }.join("-")] = value.to_s end render :nothing => true, :status => status, :location => location 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.utc) # @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 shouldn't 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.headers["Cache-Control"] = "no-cache" end end end