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Diffstat (limited to 'actionpack/lib/action_controller/base/conditional_get.rb')
| -rw-r--r-- | actionpack/lib/action_controller/base/conditional_get.rb | 133 |
1 files changed, 133 insertions, 0 deletions
diff --git a/actionpack/lib/action_controller/base/conditional_get.rb b/actionpack/lib/action_controller/base/conditional_get.rb new file mode 100644 index 0000000000..d287ec4994 --- /dev/null +++ b/actionpack/lib/action_controller/base/conditional_get.rb @@ -0,0 +1,133 @@ +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: + # * <tt>:etag</tt> + # * <tt>:last_modified</tt> + # * <tt>:public</tt> 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] + cache_control = response.headers["Cache-Control"].split(",").map {|k| k.strip } + cache_control.delete("private") + cache_control.delete("no-cache") + cache_control << "public" + response.headers["Cache-Control"] = cache_control.join(', ') + 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 + + 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 + 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: + # * <tt>:etag</tt> + # * <tt>:last_modified</tt> + # * <tt>:public</tt> 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: + cache_control = response.headers["Cache-Control"].split(",").map {|k| k.strip } + + cache_control << "max-age=#{seconds}" + cache_control.delete("no-cache") + if options[:public] + cache_control.delete("private") + cache_control << "public" + else + cache_control << "private" + end + + # This allows for additional headers to be passed through like 'max-stale' => 5.hours + cache_control += options.symbolize_keys.reject{|k,v| k == :public || k == :private }.map{ |k,v| v == true ? k.to_s : "#{k.to_s}=#{v.to_s}"} + + response.headers["Cache-Control"] = cache_control.join(', ') + 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 |