update purpose of middleware

1 files changed, 66 insertions, 11 deletions

diff --git a/guides/source/rails_on_rack.textile b/guides/source/rails_on_rack.textile
index f2cf224987..73e0f242cc 100644
--- a/guides/source/rails_on_rack.textile
+++ b/guides/source/rails_on_rack.textile
@@ -164,18 +164,73 @@ config.middleware.delete(middleware)
 
 h4. Internal Middleware Stack
 
-Much of Action Controller's functionality is implemented as Middlewares. The following table explains the purpose of each of them:
+Much of Action Controller's functionality is implemented as Middlewares. The following list explains the purpose of each of them:
 
-|_.Middleware|_.Purpose|
-|+Rack::Lock+|Sets <tt>env["rack.multithread"]</tt> flag to +true+ and wraps the application within a Mutex.|
-|+ActionController::Failsafe+|Returns HTTP Status +500+ to the client if an exception gets raised while dispatching.|
-|+ActiveRecord::QueryCache+|Enables the Active Record query cache.|
-|+ActionDispatch::Session::CookieStore+|Uses the cookie based session store.|
-|+ActionDispatch::Session::CacheStore+|Uses the Rails cache based session store.|
-|+ActionDispatch::Session::MemCacheStore+|Uses the memcached based session store.|
-|+ActiveRecord::SessionStore+|Uses the database based session store.|
-|+Rack::MethodOverride+|Sets HTTP method based on +_method+ parameter or <tt>env["HTTP_X_HTTP_METHOD_OVERRIDE"]</tt>.|
-|+Rack::Head+|Discards the response body if the client sends a +HEAD+ request.|
+ *+ActionDispatch::Static+*
+* Used to serve static assets. Disabled if <tt>config.serve_static_assets</tt> is true.
+
+ *+Rack::Lock+*
+* Sets <tt>env["rack.multithread"]</tt> flag to +true+ and wraps the application within a Mutex.
+
+ *+ActiveSupport::Cache::Strategy::LocalCache::Middleware+*
+* Used for memory caching. This cache is not thread safe.
+
+ *+Rack::Runtime+*
+* Sets an X-Runtime header, containing the time (in seconds) taken to execute the request.
+
+ *+Rack::MethodOverride+*
+* Allows the method to be overridden if <tt>params[:_method]</tt> is set. This is the middleware which supports the PUT and DELETE HTTP method types.
+
+ *+ActionDispatch::RequestId+*
+* Makes a unique +X-Request-Id+ header available to the response and enables the <tt>ActionDispatch::Request#uuid</tt> method.
+
+ *+Rails::Rack::Logger+*
+* Notifies the logs that the request has began. After request is complete, flushes all the logs.
+
+ *+ActionDispatch::ShowExceptions+*
+* Rescues any exception returned by the application and calls an exceptions app that will wrap it in a format for the end user.
+
+ *+ActionDispatch::DebugExceptions+*
+* Responsible for logging exceptions and showing a debugging page in case the request is local.
+
+ *+ActionDispatch::RemoteIp+*
+* Checks for IP spoofing attacks.
+
+ *+ActionDispatch::Reloader+*
+* Provides prepare and cleanup callbacks, intended to assist with code reloading during development.
+
+ *+ActionDispatch::Callbacks+*
+* Runs the prepare callbacks before serving the request.
+
+ *+ActiveRecord::ConnectionAdapters::ConnectionManagement+*
+* Cleans active connections after each request, unless the <tt>rack.test</tt> key in the request environment is set to +true+.
+
+ *+ActiveRecord::QueryCache+*
+* Enables the Active Record query cache.
+
+ *+ActionDispatch::Cookies+*
+* Sets cookies for the request.
+
+ *+ActionDispatch::Session::CookieStore+*
+* Responsible for storing the session in cookies.
+
+ *+ActionDispatch::Flash+*
+* Sets up the flash keys. Only available if <tt>config.action_controller.session_store</tt> is set to a value.
+
+ *+ActionDispatch::ParamsParser+*
+* Parses out parameters from the request into <tt>params</tt>.
+
+ *+ActionDispatch::Head+*
+* Converts HEAD requests to +GET+ requests and serves them as so.
+
+ *+Rack::ConditionalGet+*
+* Adds support for "Conditional +GET+" so that server responds with nothing if page wasn't changed.
+
+ *+Rack::ETag+*
+* Adds ETag header on all String bodies. ETags are used to validate cache.
+
+ *+ActionDispatch::BestStandardsSupport+*
+* Enables “best standards support” so that IE8 renders some elements correctly.
 
 TIP: It's possible to use any of the above middlewares in your custom Rack stack.