Rack

minimal interface for web servers

gem i rack

require'rack'

Rack handler

Rack::Handler.constants

A Rack application is an Ruby object (not a class) that responds to call. It takes exactly one argument, the environment and returns an Array of exactly three values: The status, the headers, and the body.

Ruby object that responds to call

object

lambda or proc

method

->{}.call

It takes exactly one argument, the environment and returns an Array of exactly three values: The status, the headers, and the body.

->(env){[200, {}, [Hello Saito]]}

Rack::Handler::Thin.run ->(env){[200, {}, ["Hey Saito"]]}

Middleware

class Decorator
def initialize(app)
@app = app
end

def call(env)
status, headers, body = @app.call(env)
[status, headers, body]
end
end

Rack::Handler::Thin.run Decorator(->(env){[200, {}, ["Hey Saito"]]})

Rack middleware is also a rack application.

Sinatra

Sinatra is a DSL for quickly creating web applications in Ruby with minimal effort

require'sinatra'

get '/' do 'Hello saito!' end

REST, RFC-2616

get, post, put, patch, delete, options

Rails pull request 505

Sinatra-contrib

sinatra/reloader
sinatra/namespace
sinatra/respond_with

…

Padrino

the Godfather of Sinatra

Key Features

Admin

Helpers Generators Mountable

Padrino is another Rails

Others

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