builder

gistfile1.rb

require 'debugger'
class Builder
  def initialize(&block)
    @wares = []
    @runner = nil
    instance_eval(&block) if block_given?
  end

  def use(middleware, *args, &block)
    @wares << if block_given?
      lambda { |app| middleware.new(app, *args, &block) }
    else
      lambda { |app| middleware.new(app, *args) }
    end
  end

  def run(runner, *args, &block)
    # runner is the entry point, you can think of it as the 
    # first middleware to run.
    @runner = lambda { |env|
      env = "I set a runner to #{runner}"
      # env[:response] = Response.new
      env
    }
    @runner
  end
  
  def to_app
    # want to use @runner here rather than @wares.last?
    # @wares << @runner
    # @wares[0...-1].reverse.inject(@wares.last) { |a,e| e.call(a) }
    @wares.inject(@runner) { |a,e| e.call(a) }
  end

  def call(env)
    to_app.call(env)
  end
end


class FirstMiddleware
  def initialize(app = nil, args, &block)
    @app = app
    @args = args
    puts "init: FirstMiddleware.new(#{app}, #{args})"
  end
  
  def call(env)
    resp = @app.call(env)
    puts "FirstMiddleware call env: #{env}, #{@args}"
    resp += ", #{@args}"
    resp
  end
  def inspect() "FirstMiddleware - 1" end
end

class SecondMiddleware
  def initialize(app = nil, args, &block)
    @app = app
    @args = args
    @block = instance_eval(&block) if block_given?
    puts "init: SecondMiddleware.new(#{app}, #{args})"
  end

  def call(env)
    resp = @app.call(env)
    puts "SecondMiddleware call env: #{env}, #{@args}"
    resp.upcase! # += ", #{@args}"
    resp
  end
  
  def current_user=(x)
    @current_user = x
  end
  def inspect() "SecondMiddleware - 1" end
end

class Runner
  def initialize(app = nil)

    puts "RUNNER INIT HAS: #{app}"
    app
  end
  # 
  # def call(env)
  #   puts "RUNNER HAS: #{env}"
  #   @app.call(env)
  # end
end

app = Builder.new {
  use FirstMiddleware, 'first_arg'
  use( SecondMiddleware, 'second_arg') { |t|
    t.current_user= "aoeu"
  }
  run Runner
}

puts "result: #{app.call('start')}"

puts "app.inspect: #{app.inspect}"
a = 2