Allow cache to be re-generated on-demand without first deleting it

README.md

@@ -119,6 +119,10 @@ indicates a HTML request the fragment is stored without the
 extension but if an explicit `"html"` is passed in `:format` then
 that _is_ used for storing the fragment.
 
+If you would like your cache to be regenerated on-demand without
+first clearing it, you can append a `cache=force` param to your
+URL (ex: `http://mysite.com/videos/list?cache=force`).
+
 Contributing
 ------------
 

lib/action_controller/caching/actions.rb

@@ -156,7 +156,9 @@ def around(controller)
           path_options = expand_option(controller, @cache_path)
           cache_path = ActionCachePath.new(controller, path_options || {})
 
-          body = controller.read_fragment(cache_path.path, @store_options)
+          unless controller.params[:cache] == 'force'
+            body = controller.read_fragment(cache_path.path, @store_options)
+          end
 
           unless body
             controller.action_has_layout = false unless cache_layout

test/caching_test.rb

@@ -48,6 +48,7 @@ class ActionCachingTestController < CachingController
   caches_action :streaming
   caches_action :invalid
   caches_action :accept
+  caches_action :regenerate
 
   layout "talk_from_action"
 
@@ -142,6 +143,11 @@ def accept
     end
   end
 
+  def regenerate
+    @cache_this = MockTime.now.to_f.to_s
+    render plain: @cache_this
+  end
+
   def expire_accept
     if params.key?(:format)
       expire_action action: "accept", format: params[:format]
@@ -853,6 +859,22 @@ def test_lambda_arity_with_layout
     assert_equal cached_time, read_fragment("hostname.com/action_caching_test/with_layout_proc_param_no_args")
   end
 
+  def test_regenerate_without_expiring
+    draw do
+      get "/action_caching_test/regenerate", to: "action_caching_test#regenerate"
+    end
+
+    get :regenerate
+    cached_time = content_to_cache
+    assert_equal cached_time, @response.body
+    assert fragment_exist?("hostname.com/action_caching_test/regenerate")
+
+    get :regenerate, params: { cache: 'force' }
+    updated_cached_time = content_to_cache
+    assert_equal updated_cached_time, @response.body
+    assert_equal read_fragment("hostname.com/action_caching_test/regenerate"), updated_cached_time
+  end
+
   private
     def get_html(*args)
       @request.accept = "text/html"