From bd6b61be88dfe6eb1ff1dcc5c17542d804a842c7 Mon Sep 17 00:00:00 2001
From: Yehuda Katz <wycats@gmail.com>
Date: Thu, 6 Aug 2009 19:52:11 -0300
Subject: Rename /base to /metal and make base.rb and metal.rb top-level to
 reflect their module locations

---
 .../lib/action_controller/metal/conditional_get.rb | 118 +++++++++++++++++++++
 1 file changed, 118 insertions(+)
 create mode 100644 actionpack/lib/action_controller/metal/conditional_get.rb

(limited to 'actionpack/lib/action_controller/metal/conditional_get.rb')

diff --git a/actionpack/lib/action_controller/metal/conditional_get.rb b/actionpack/lib/action_controller/metal/conditional_get.rb
new file mode 100644
index 0000000000..6d35137428
--- /dev/null
+++ b/actionpack/lib/action_controller/metal/conditional_get.rb
@@ -0,0 +1,118 @@
+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]
+        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
+
+      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:
+      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
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