Rack A interface por trás dos frameworks web em Ruby 

Oi, eu sou o Phil 

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O que é Rack? 

Ruby Gem 

"Uma interface Ruby para webservers” 

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careers.plataformatec.com.br 

Servidor de aplicação Aplicação Ruby Navegador GET careers.plataformatec.com.br HTTP Rack API P U M A 

Mas como é essa interface? 

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class MyApp def call(env) status = 200 # ok headers = {'Content-Type' => 'text/html'} body = ['

Hello Rubyconf!

'] [status, headers, body] end end 

class MyApp def call(env) status = 200 # ok headers = {'Content-Type' => 'text/html'} body = ['

Hello Rubyconf!

’] [status, headers, body] end end { "HTTP_ACCEPT" => “text/html, ...", "HTTP_USER_AGENT" => "Mozilla/5.0...", "REQUEST_PATH" => "/posts", "REQUEST_METHOD" => "GET", "rack.version" => [1, 3], "rack.request.query_string" => "", "rack.request.query_hash" => {}, "rack.request.cookie_hash" => {} ... } 

class MyApp def call(env) status = 200 # ok headers = {'Content-Type' => 'text/html'} body = ['

Hello Rubyconf!

'] [status, headers, body] end end 

~código ao vivo~ 

Middlewares 

Módulos que ajudam a processar uma requisição 

Pipeline 

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careers.plataformatec.com.br 

M iddlew are 1 M iddlew are 2 M iddlew are 3 M iddlew are 4 REQUISIÇÃO RESPOSTA 

Com m onLogger M iddlew are 2 M iddlew are 3 M iddlew are 4 127.0.0.1 - - [07/Nov/2017:00:46:36 -0200] "GET / HTTP/1.1" 200 - 0.0003 127.0.0.1 - - [07/Nov/2017:00:46:41 -0200] "GET / HTTP/1.1" 200 - 0.0003 127.0.0.1 - - [07/Nov/2017:00:46:41 -0200] "GET / HTTP/1.1" 200 - 0.0003 127.0.0.1 - - [07/Nov/2017:00:46:45 -0200] "GET / HTTP/1.1" 200 - 0.0003 127.0.0.1 - - [07/Nov/2017:00:46:55 -0200] "GET /products/2 HTTP/1.1" 200 - 0.0003 127.0.0.1 - - [07/Nov/2017:00:47:02 -0200] "GET /products/2 HTTP/1.1" 200 - 0.0003 127.0.0.1 - - [07/Nov/2017:00:47:04 -0200] "GET /products HTTP/1.1" 200 - 0.0005 127.0.0.1 - - [07/Nov/2017:00:47:05 -0200] "GET /products/1 HTTP/1.1" 200 - 0.0003 127.0.0.1 - - [07/Nov/2017:00:47:07 -0200] "GET /products/3 HTTP/1.1" 200 - 0.0003 127.0.0.1 - - [07/Nov/2017:00:47:09 -0200] "GET /products/2 HTTP/1.1" 200 - 0.0005 

M iddlew are 3 M iddlew are 4 a Com m onLogger Autenticação 401 UNAUTHORIZED ⛔ 

class MyMiddleware def initialize(app) @app = app end def call(env) # before logic @app.call(env) # after* logic end end 

class MyMiddleware def initialize(app) @app = app end def call(env) # before logic @app.call(env) # after* logic end end 

class MyMiddleware def initialize(app) @app = app end def call(env) # before logic @app.call(env) # after* logic end end 

class MyMiddleware def initialize(app) @app = app end def call(env) # before logic @app.call(env) # after* logic end end 

class MyMiddleware def initialize(app) @app = app end def call(env) # before logic @app.call(env) # after* logic end end 

• Conexão com o banco de dados • Autenticação • Telas de erro (exceção) • Rate limit • Controle de cookies • Roteamento • Recarregamento automático de código • Profiling • Arquivos estáticos 

Funciona com qualquer framework baseado em Rack ✨ 

$ rails middleware 

use Rack::Sendfile use ActionDispatch::Static use ActionDispatch::Executor use Rack::Runtime use Rack::MethodOverride use ActionDispatch::RequestId use ActionDispatch::RemoteIp use Sprockets::Rails::QuietAssets use Rails::Rack::Logger use ActionDispatch::ShowExceptions use WebConsole::Middleware use ActionDispatch::DebugExceptions use ActionDispatch::Reloader use ActionDispatch::Callbacks use ActiveRecord::Migration::CheckPending use ActionDispatch::Cookies ... 

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class ActiveRecord::Migration::CheckPending def initialize(app) @app = app end def call(env) # raises error if there are pending migrations ActiveRecord::Migration.check_pending!(connection) @app.call(env) end def connection ActiveRecord::Base.connection end end 

class ActiveRecord::Migration::CheckPending def initialize(app) @app = app end def call(env) # raises error if there are pending migrations ActiveRecord::Migration.check_pending!(connection) @app.call(env) end def connection ActiveRecord::Base.connection end end 

Problemas 

Template Streaming (Rails 3) 

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Como funciona internamente 

class MyApp def call(env) status = 200 # ok headers = {'Content-Type' => 'text/html'} body_html = [ 'My e-commerce!’, lazy_view ] [status, headers, body_html] end end 

class MyApp def call(env) status = 200 # ok headers = {'Content-Type' => 'text/html'} body_html = [ 'My e-commerce!', lazy_view ] [status, headers, body_html] end end 

class MyApp def call(env) status = 200 # ok headers = {'Content-Type' => 'text/html'} body_html = [ 'My e-commerce!', lazy_view ] [status, headers, body_html] end end 

class MyApp def call(env) status = 200 # ok headers = {'Content-Type' => 'text/html'} body_html = [ 'My e-commerce!', lazy_view ] [status, headers, body_html] end end 

O problema 

class DBConnectionMiddleware def call(env) connection = DB.checkout_connection env['db.connection'] = connection @app.call(env) ensure DB.checkin_connection connection end end 

class DBConnectionMiddleware def call(env) connection = DB.checkout_connection env['db.connection'] = connection @app.call(env) ensure DB.checkin_connection connection end end 

class DBConnectionMiddleware def call(env) connection = DB.checkout_connection env['db.connection'] = connection @app.call(env) ensure DB.checkin_connection connection end end 

class DBConnectionMiddleware def call(env) connection = DB.checkout_connection env['db.connection'] = connection @app.call(env) ensure DB.checkin_connection connection end end 

class DBConnectionMiddleware def call(env) connection = DB.checkout_connection env['db.connection'] = connection @app.call(env) ensure DB.checkin_connection connection end end 

http://bit.ly/tenderlove_rack_api 

http://bit.ly/valim_rack_api 

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A Web está (sempre) mudando 

Existem fluxos que fogem do modelo pedido / resposta 

Websockets ↔ (Action Cable) 

build passou ✅ novo comentário análise de código completa ✅ GitHub conexão bidirecional 

Server push (HTTP/2) ⏩ 

carreers.plataformatec.com.br index.html logo.png layout.css 

class MyApp def call(env) status = 200 # ok headers = {'Content-Type' => 'text/html'} body = ['

Hello Rubyconf!

’] [status, headers, body] end end 1 requisição 1 resposta 

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Rack 3 

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Streams 

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Eventos 

✂ middlewares (Node.js / Connect) 

Retrocompatível 

Conclusões 

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Conheça o funcionamento das coisas que você usa ⚙ 

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Bons exemplos 

Entender e resolver problemas 

Estamos contratando! http://careers.plataformatec.com.br 

Obrigado! peagha @philHenri