Parser HTTP em Ruby

parser.rb

class Parser
  END_OF_HEADERS = /\r\n\r\n/

  attr_accessor :method, :version, :headers, :path

  def initialize
    @data      = ""
    @completed = false
    @headers   = {}
  end

  def feed(partial)
    @data << partial

    if @data =~ END_OF_HEADERS
      process!(@data)
    end
  end

  def process!(data)
    lines = data.split("\r\n")

    # GET /check HTTP/1.1
    # @method   = GET
    # @path     = /check
    # @version  = HTTP/1.1
    @method, @path, @version = lines.shift.split(" ")

    lines.each do |line|
      name, value = line.split(":", 2)
      @headers[name] = value.lstrip
    end

    @completed = true
  end

  def completed?
    @completed
  end
end

parser_spec.rb

require_relative './parser'

describe Parser do
  let(:parser) { described_class.new }

  def each_chunk(file)
    size = 10
    open(file, 'rb') do |f|
      yield f.read(size) until f.eof?
    end
  end

  it 'parser http request' do
    each_chunk('request.txt') do |chunk|
      parser.feed(chunk)
    end

    expect(parser).to be_completed
    expect(parser.method).to  eq('GET')
    expect(parser.path).to    eq('/')
    expect(parser.version).to eq('HTTP/1.1')
    expect(parser.headers).to eq({
      'Host'       => 'localhost:8000',
      'User-Agent' => 'curl/7.51.0',
      'Accept'     => '*/*'
    })
  end
end

request.txt

GET / HTTP/1.1
Host: localhost:8000
User-Agent: curl/7.51.0
Accept: */*