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Diffstat (limited to 'railties/guides/source/rails_on_rack.textile')
| -rw-r--r-- | railties/guides/source/rails_on_rack.textile | 51 |
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diff --git a/railties/guides/source/rails_on_rack.textile b/railties/guides/source/rails_on_rack.textile index 512be43668..eaebb05f17 100644 --- a/railties/guides/source/rails_on_rack.textile +++ b/railties/guides/source/rails_on_rack.textile @@ -222,57 +222,6 @@ use MyOwnStackFromStratch run ActionController::Dispatcher.new </ruby> -h3. Rails Metal Applications - -Rails Metal applications are minimal Rack applications specially designed for integrating with a typical Rails application. As Rails Metal Applications skip all of the Action Controller stack, serving a request has no overhead from the Rails framework itself. This is especially useful for infrequent cases where the performance of the full stack Rails framework is an issue. - -Ryan Bates' "Railscast on Rails Metal":http://railscasts.com/episodes/150-rails-metal provides a nice walkthrough generating and using Rails Metal. - -h4. Generating a Metal Application - -Rails provides a generator called +metal+ for creating a new Metal application: - -<shell> -$ rails generate metal poller -</shell> - -This generates +poller.rb+ in the +app/metal+ directory: - -<ruby> -# Allow the metal piece to run in isolation -require(File.dirname(__FILE__) + "/../../config/environment") unless defined?(Rails) - -class Poller - def self.call(env) - if env["PATH_INFO"] =~ /^\/poller/ - [200, {"Content-Type" => "text/html"}, ["Hello, World!"]] - else - [404, {"Content-Type" => "text/html", "X-Cascade" => "pass"}, ["Not Found"]] - end - end -end -</ruby> - -Metal applications within +app/metal+ folders in plugins will also be discovered and added to the list. - -Metal applications are an optimization. You should make sure to "understand the related performance implications":http://weblog.rubyonrails.org/2008/12/20/performance-of-rails-metal before using it. - -WARNING: To continue the Metal chain execution, return an +X-Cascade+ HTTP header with a value of +pass+. - -h4. Execution Order - -All Metal Applications are executed in alphabetical order of their filenames, so +aaa.rb+ will come before +bbb.rb+ in the metal chain. - -You can override the default ordering in your environment. Simply add a line like the following to +config/application.rb+ - -It is, however, possible to override the default ordering in your environment. Simply add a line like the following to +config/environment.rb+ - -<ruby> -config.metals = ["Bbb", "Aaa"] -</ruby> - -Each string in the array should be the name of your metal class. If you do this then be warned that any metal applications not listed will not be loaded. - h3. Resources h4. Learning Rack |