Learn Rails Inside and Out: Rack example code

config.ru

require 'rack'
your_app = Proc.new { [200, {}, ["Hello World!"]] }
Rack::Server.start app: your_app, Port: 9292

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your_app = proc { [200, {}, ["Hello World!"]] }
run your_app

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run proc { [200, {}, ["<h1>Hello World!</h1>"]] }

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run proc { [200, { "Content-Type" => "text/html" }, ["<h1>Hello World!</h1>"]] }

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# encoding: utf-8
run proc { [200, { "Content-Type" => "text/html; charset=utf-8" }, ["<h1>Hello World! 👍</h1>"]] }

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run proc { |env| [200, {}, ["env is a #{env.class}"]] }

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run proc { |env|

  list = env.map do |key, value|
    "<dt>#{key}</dt>" +
    "<dd>#{value.inspect.gsub('<', '&lt;')}</dd>"
  end
  [200, { "Content-Type" => "text/html" }, ["<dl>", *list, "</dl>"]]

}

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run proc { |env|

  params = Rack::Utils.parse_query(env['QUERY_STRING'])
  name = params["name"]
  [200, { "Content-Type" => "text/html" }, ["Your name is #{name}"]]

}

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run proc { |env|

  request = Rack::Request.new(env)
  name = request.params["name"]
  [200, { "Content-Type" => "text/html" }, ["Your name is #{name}"]]

}

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run proc { |env|

  request = Rack::Request.new(env)
  methods = request.public_methods(false).sort.map { |m| "<li>#{m}</li>" }
  [200, { "Content-Type" => "text/html" }, ['<ul>', *methods, '</ul>']]

}

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class DumbLogger
  def initialize(app)
    @app = app
  end
  def call(env)
    start = Time.now
    status, headers, body = @app.call(env)
    finish = Time.now
    [status, headers, body + ["\n<!-- Request took #{finish - start} seconds -->"]]
  end
end

use DumbLogger
run proc { |env| sleep(1); [200, {}, ["hello"]] }

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class CoreValueHeader
  VALUES = [
    "1. Deliver WOW Through Service",
    "2. Embrace and Drive Change",
    "3. Create Fun and A Little Weirdness",
    "4. Be Adventurous, Creative, and Open-Minded",
    "5. Pursue Growth and Learning",
    "6. Build Open and Honest Relationships With Communication",
    "7. Build a Positive Team and Family Spirit",
    "8. Do More With Less",
    "9. Be Passionate and Determined",
    "10. Be Humble"
  ]

  def initialize(app)
    @app = app
  end

  def call(env)
    status, headers, body = @app.call(env)
    [status, headers.merge({ "X-Core-Value" => VALUES.sample(1).first }), body]
  end
end

use CoreValueHeader
run proc { [200, { "Content-Type" => "text/html" }, ["Hello World"]] }

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class Router
  def call(env)
    # controller.action(action).call(env)
    [200, {}, ["router called"]]
  end
end

run Router.new

#####################

# /foo/bar
class FooController
  def bar
    "hi from foo#bar"
  end
end

#####################

class Router
  def call(env)
    # "/foo/bar" => ["/", "foo", "bar"]
    url_parts = env['REQUEST_PATH'].split("/")
    controller_name = url_parts[1]
    action = url_parts[2].to_sym

    controller_name = "#{controller_name.capitalize}Controller"
    controller = Kernel.const_get(controller_name)

    controller.action(action).call(env)
  end
end

#####################

class BaseController
  def self.action(action_name)
    lambda { |env|
      [200, {}, ["BaseController::action called"]]
    }
  end
end

class FooController < BaseController
end

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lambda { |env|
  [200, {}, [self.new.send(action_name)]]
}

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def call(env)
rescue NoMethodError
  [404, {}, ["Not Found (action missing)"]]
end

#####################

def baz
  "FOO! BAZ!"
end

#####################

def baz
  @things = %w{one two three}
  template = File.read("foo/baz.html.erb")
  ERB.new(template).result(binding).to_s
end

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require 'action_controller'

class FooController < ActionController::Metal
  include ActionController::Rendering
  append_view_path File.dirname(__FILE__)

  def bar
    self.response_body = "hi from foo#bar"
  end

  def baz
    @things = %w{one two three}
    render "foo/baz"
  end
end

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require 'sinatra'

class MyApp < Sinatra::Base
  get '/foo/bar' do
    "hi from foo#bar"
  end

  get '/foo/baz' do
    @things = %w{one two three}
    erb :baz, views: File.dirname(__FILE__) + "/foo"
  end
end

run MyApp