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Diffstat (limited to 'guides/source/rails_on_rack.md')
| -rw-r--r-- | guides/source/rails_on_rack.md | 101 |
1 files changed, 46 insertions, 55 deletions
diff --git a/guides/source/rails_on_rack.md b/guides/source/rails_on_rack.md index d8477d89e3..9c92cf3aea 100644 --- a/guides/source/rails_on_rack.md +++ b/guides/source/rails_on_rack.md @@ -5,7 +5,6 @@ This guide covers Rails integration with Rack and interfacing with other Rack co After reading this guide, you will know: -* How to create Rails Metal applications. * How to use Rack Middlewares in your Rails applications. * Action Pack's internal Middleware stack. * How to define a custom Middleware stack. @@ -28,7 +27,10 @@ Rails on Rack ### Rails Application's Rack Object -`ApplicationName::Application` is the primary Rack application object of a Rails application. Any Rack compliant web server should be using `ApplicationName::Application` object to serve a Rails application. +`ApplicationName::Application` is the primary Rack application object of a Rails +application. Any Rack compliant web server should be using +`ApplicationName::Application` object to serve a Rails +application. `Rails.application` refers to the same application object. ### `rails server` @@ -79,11 +81,11 @@ To use `rackup` instead of Rails' `rails server`, you can put the following insi ```ruby # Rails.root/config.ru -require "config/environment" +require ::File.expand_path('../config/environment', __FILE__) -use Rack::Debugger +use Rails::Rack::Debugger use Rack::ContentLength -run ApplicationName::Application +run Rails.application ``` And start the server: @@ -101,7 +103,7 @@ $ rackup --help Action Dispatcher Middleware Stack ---------------------------------- -Many of Action Dispatchers's internal components are implemented as Rack middlewares. `Rails::Application` uses `ActionDispatch::MiddlewareStack` to combine various internal and external middlewares to form a complete Rails Rack application. +Many of Action Dispatcher's internal components are implemented as Rack middlewares. `Rails::Application` uses `ActionDispatch::MiddlewareStack` to combine various internal and external middlewares to form a complete Rails Rack application. NOTE: `ActionDispatch::MiddlewareStack` is Rails equivalent of `Rack::Builder`, but built for better flexibility and more features to meet Rails' requirements. @@ -116,6 +118,7 @@ $ rake middleware For a freshly generated Rails application, this might produce something like: ```ruby +use Rack::Sendfile use ActionDispatch::Static use Rack::Lock use #<ActiveSupport::Cache::Strategy::LocalCache::Middleware:0x000000029a0838> @@ -128,6 +131,7 @@ use ActionDispatch::DebugExceptions use ActionDispatch::RemoteIp use ActionDispatch::Reloader use ActionDispatch::Callbacks +use ActiveRecord::Migration::CheckPending use ActiveRecord::ConnectionAdapters::ConnectionManagement use ActiveRecord::QueryCache use ActionDispatch::Cookies @@ -140,7 +144,7 @@ use Rack::ETag run MyApp::Application.routes ``` -Purpose of each of this middlewares is explained in the [Internal Middlewares](#internal-middleware-stack) section. +The default middlewares shown here (and some others) are each summarized in the [Internal Middlewares](#internal-middleware-stack) section, below. ### Configuring Middleware Stack @@ -178,18 +182,17 @@ You can swap an existing middleware in the middleware stack using `config.middle config.middleware.swap ActionDispatch::ShowExceptions, Lifo::ShowExceptions ``` -#### Middleware Stack is an Enumerable +#### Deleting a Middleware -The middleware stack behaves just like a normal `Enumerable`. You can use any `Enumerable` methods to manipulate or interrogate the stack. The middleware stack also implements some `Array` methods including `[]`, `unshift` and `delete`. Methods described in the section above are just convenience methods. - -Append following lines to your application configuration: +Add the following lines to your application configuration: ```ruby # config/application.rb config.middleware.delete "Rack::Lock" ``` -And now if you inspect the middleware stack, you'll find that `Rack::Lock` will not be part of it. +And now if you inspect the middleware stack, you'll find that `Rack::Lock` is +not a part of it. ```bash $ rake middleware @@ -221,118 +224,106 @@ config.middleware.delete "Rack::MethodOverride" Much of Action Controller's functionality is implemented as Middlewares. The following list explains the purpose of each of them: - **`ActionDispatch::Static`** +**`Rack::Sendfile`** + +* Sets server specific X-Sendfile header. Configure this via `config.action_dispatch.x_sendfile_header` option. -* Used to serve static assets. Disabled if `config.serve_static_assets` is true. +**`ActionDispatch::Static`** - **`Rack::Lock`** +* Used to serve static assets. Disabled if `config.serve_static_assets` is `false`. + +**`Rack::Lock`** * Sets `env["rack.multithread"]` flag to `false` and wraps the application within a Mutex. - **`ActiveSupport::Cache::Strategy::LocalCache::Middleware`** +**`ActiveSupport::Cache::Strategy::LocalCache::Middleware`** * Used for memory caching. This cache is not thread safe. - **`Rack::Runtime`** +**`Rack::Runtime`** * Sets an X-Runtime header, containing the time (in seconds) taken to execute the request. - **`Rack::MethodOverride`** +**`Rack::MethodOverride`** * Allows the method to be overridden if `params[:_method]` is set. This is the middleware which supports the PUT and DELETE HTTP method types. - **`ActionDispatch::RequestId`** +**`ActionDispatch::RequestId`** * Makes a unique `X-Request-Id` header available to the response and enables the `ActionDispatch::Request#uuid` method. - **`Rails::Rack::Logger`** +**`Rails::Rack::Logger`** * Notifies the logs that the request has began. After request is complete, flushes all the logs. - **`ActionDispatch::ShowExceptions`** +**`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`** +**`ActionDispatch::DebugExceptions`** * Responsible for logging exceptions and showing a debugging page in case the request is local. - **`ActionDispatch::RemoteIp`** +**`ActionDispatch::RemoteIp`** * Checks for IP spoofing attacks. - **`ActionDispatch::Reloader`** +**`ActionDispatch::Reloader`** * Provides prepare and cleanup callbacks, intended to assist with code reloading during development. - **`ActionDispatch::Callbacks`** +**`ActionDispatch::Callbacks`** * Runs the prepare callbacks before serving the request. - **`ActiveRecord::ConnectionAdapters::ConnectionManagement`** +**`ActiveRecord::Migration::CheckPending`** + +* Checks pending migrations and raises `ActiveRecord::PendingMigrationError` if any migrations are pending. + +**`ActiveRecord::ConnectionAdapters::ConnectionManagement`** * Cleans active connections after each request, unless the `rack.test` key in the request environment is set to `true`. - **`ActiveRecord::QueryCache`** +**`ActiveRecord::QueryCache`** * Enables the Active Record query cache. - **`ActionDispatch::Cookies`** +**`ActionDispatch::Cookies`** * Sets cookies for the request. - **`ActionDispatch::Session::CookieStore`** +**`ActionDispatch::Session::CookieStore`** * Responsible for storing the session in cookies. - **`ActionDispatch::Flash`** +**`ActionDispatch::Flash`** * Sets up the flash keys. Only available if `config.action_controller.session_store` is set to a value. - **`ActionDispatch::ParamsParser`** +**`ActionDispatch::ParamsParser`** * Parses out parameters from the request into `params`. - **`ActionDispatch::Head`** +**`ActionDispatch::Head`** * Converts HEAD requests to `GET` requests and serves them as so. - **`Rack::ConditionalGet`** +**`Rack::ConditionalGet`** * Adds support for "Conditional `GET`" so that server responds with nothing if page wasn't changed. - **`Rack::ETag`** +**`Rack::ETag`** * Adds ETag header on all String bodies. ETags are used to validate cache. TIP: It's possible to use any of the above middlewares in your custom Rack stack. -### Using Rack Builder - -The following shows how to replace use `Rack::Builder` instead of the Rails supplied `MiddlewareStack`. - -<strong>Clear the existing Rails middleware stack</strong> - -```ruby -# config/application.rb -config.middleware.clear -``` - -<br /> -<strong>Add a `config.ru` file to `Rails.root`</strong> - -```ruby -# config.ru -use MyOwnStackFromScratch -run ApplicationName::Application -``` - Resources --------- ### Learning Rack -* [Official Rack Website](http://rack.github.com) +* [Official Rack Website](http://rack.github.io) * [Introducing Rack](http://chneukirchen.org/blog/archive/2007/02/introducing-rack.html) * [Ruby on Rack #1 - Hello Rack!](http://m.onkey.org/ruby-on-rack-1-hello-rack) * [Ruby on Rack #2 - The Builder](http://m.onkey.org/ruby-on-rack-2-the-builder) |