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Diffstat (limited to 'guides/source/rails_on_rack.textile')
| -rw-r--r-- | guides/source/rails_on_rack.textile | 123 |
1 files changed, 84 insertions, 39 deletions
diff --git a/guides/source/rails_on_rack.textile b/guides/source/rails_on_rack.textile index 9526526bc7..ff862273fd 100644 --- a/guides/source/rails_on_rack.textile +++ b/guides/source/rails_on_rack.textile @@ -91,13 +91,15 @@ For a freshly generated Rails application, this might produce something like: <ruby> use ActionDispatch::Static use Rack::Lock -use ActiveSupport::Cache::Strategy::LocalCache +use #<ActiveSupport::Cache::Strategy::LocalCache::Middleware:0x000000029a0838> use Rack::Runtime +use Rack::MethodOverride +use ActionDispatch::RequestId use Rails::Rack::Logger use ActionDispatch::ShowExceptions use ActionDispatch::DebugExceptions use ActionDispatch::RemoteIp -use Rack::Sendfile +use ActionDispatch::Reloader use ActionDispatch::Callbacks use ActiveRecord::ConnectionAdapters::ConnectionManagement use ActiveRecord::QueryCache @@ -105,8 +107,9 @@ use ActionDispatch::Cookies use ActionDispatch::Session::CookieStore use ActionDispatch::Flash use ActionDispatch::ParamsParser -use Rack::MethodOverride use ActionDispatch::Head +use Rack::ConditionalGet +use Rack::ETag use ActionDispatch::BestStandardsSupport run Blog::Application.routes </ruby> @@ -145,62 +148,104 @@ You can swap an existing middleware in the middleware stack using +config.middle <ruby> # config/application.rb -# Replace ActionController::Failsafe with Lifo::Failsafe -config.middleware.swap ActionController::Failsafe, Lifo::Failsafe +# Replace ActionDispatch::ShowExceptions with Lifo::ShowExceptions +config.middleware.swap ActionDispatch::ShowExceptions, Lifo::ShowExceptions </ruby> h5. Middleware Stack is an Array The middleware stack behaves just like a normal +Array+. You can use any +Array+ methods to insert, reorder, or remove items from the stack. Methods described in the section above are just convenience methods. -For example, the following removes the middleware matching the supplied class name: +Append following lines to your application configuration: <ruby> -config.middleware.delete(middleware) +# config/application.rb +config.middleware.delete "Rack::Lock" </ruby> +And now if you inspect the middleware stack, you'll find that +Rack::Lock+ will not be part of it. + +<shell> +$ rake middleware +(in /Users/lifo/Rails/blog) +use ActionDispatch::Static +use #<ActiveSupport::Cache::Strategy::LocalCache::Middleware:0x00000001c304c8> +use Rack::Runtime +... +run Myapp::Application.routes +</shell> + 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. -TIP: It's possible to use any of the above middlewares in your custom Rack stack. + *+Rack::Lock+* +* Sets <tt>env["rack.multithread"]</tt> flag to +true+ and wraps the application within a Mutex. -h4. Customizing Internal Middleware Stack + *+ActiveSupport::Cache::Strategy::LocalCache::Middleware+* +* Used for memory caching. This cache is not thread safe. -It's possible to replace the entire middleware stack with a custom stack using <tt>ActionController::Dispatcher.middleware=</tt>. + *+Rack::Runtime+* +* Sets an X-Runtime header, containing the time (in seconds) taken to execute the request. -Put the following in an initializer: + *+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. -<ruby> -# config/initializers/stack.rb -ActionController::Dispatcher.middleware = ActionController::MiddlewareStack.new do |m| - m.use ActionController::Failsafe - m.use ActiveRecord::QueryCache - m.use Rack::Head -end -</ruby> + *+ActionDispatch::RequestId+* +* Makes a unique +X-Request-Id+ header available to the response and enables the <tt>ActionDispatch::Request#uuid</tt> method. -And now inspecting the middleware stack: + *+Rails::Rack::Logger+* +* Notifies the logs that the request has began. After request is complete, flushes all the logs. -<shell> -$ rake middleware -(in /Users/lifo/Rails/blog) -use ActionController::Failsafe -use ActiveRecord::QueryCache -use Rack::Head -run ActionController::Dispatcher.new -</shell> + *+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. h4. Using Rack Builder |