Rack: a Ruby Webserver Interface

• (F)CGI
• mod_rails
• mongrel handler
• apache proxy + cluster of mongrels
• meanwhile, Python already had WSGI

• Apache/Passenger
• Nginx/Passenger
• Puma
• Unicorn
• Webrick ;)
• Thin
• Rainbows
• name it!

describe 'rack interface' do  it 'should respond to call and accept hash'  it 'should return [status, headers, and chunks of body]'end

lambda do |env|
  body = "Hello, World!"
    [ 200,    { "Content-Type" =>  "text/plain",      "Content-Length" => body.length.to_s },           [body]  ]
end

 class RackAwesomeMiddleware
    def call(env)      body = "Rack is awesome!"
      [ 200,         {"Content-Type" => "text/plain",          "Content-Length" => body.length.to_s},             [body]      ]    end
 end

use Rack::Reloader, 0
use Rack::ContentLength

app = proc do |env|
  [ 200, {'Content-Type' => 'text/plain'}, ["a"] ]
end

run app

$ rackup config.ru # starts the app

class AwesomeMiddleware  def initialize app    @app = app  end
  def call(env)    @app.call env  endend 

class AwesomeMiddleware  def initialize app    @app = app  end
  def call(env)    res = @app.call(env)    res[1]["Server"] = "Awesome Server"    res  endend 

class AwesomeMiddleware  def initialize app    @app = app  end
  def call(env)    env["RAILS_ENV"] = 'awesome'    @app.call env  endend 

require ::File.expand_path('../config/environment',  __FILE__)
run Rails.application 

 # config/environments/staging.rb
  config.middleware.insert_before(::Rack::Runtime,     "::BasicAuthMiddleware", "Staging") do |u, p|
    u == 'secret' && p == 'password'

  end

class ConfigurableMiddleware  def initialize(app, &block)     config = OpenStruct.new     yield config     ...  endend
# confug.ru / config/environments/*.rbconfig.middleware.use 'ConfigurableMiddleware' do |config|  config.foo = 'bar'end

use Rack::Sendfile
use ActionDispatch::Static
use Rack::Lock
use Rack::Runtime
use Rack::MethodOverride
use ActionDispatch::RequestId
use Rails::Rack::Logger
use ActionDispatch::ShowExceptions
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
use ActionDispatch::Session::CookieStore
use ActionDispatch::Flash
use ActionDispatch::ParamsParser
use Rack::Head
use Rack::ConditionalGet
use Rack::ETag
run MyApp::Application.routes