178 downloader

dl.rb

#!/usr/bin/env ruby

require 'nokogiri'
require 'open-uri'
require 'execjs'
require 'net/http'
require "em-synchrony"
require "em-synchrony/em-http"
require "em-synchrony/fiber_iterator"

HOST = 'http://imgfast.manhua.178.com/'

url = ARGV[0]
doc = Nokogiri::HTML(open(url))
script = doc.css('script')[0]

dir = doc.css('title')[0].content
Dir.mkdir dir unless Dir.exists? dir

context = ExecJS.compile(script.content)
urls = context.eval("arr_pages").map { |page| "#{HOST}#{URI.encode(URI.decode(page))}" }

EM.synchrony do
  concurrency = 10
  EM::Synchrony::FiberIterator.new(urls, concurrency).each do |url|
    index = urls.index(url) + 1
    p "#{index} of #{urls.count}"
  	http = EventMachine::HttpRequest.new(url).get
  	file = open("#{dir}/#{'%03d' % index}.jpg", "wb")
  	file.write(http.response)
  	file.close
  end
  EventMachine.stop
  system("zip #{dir} #{dir}/*")
  system("rm -rf #{dir}")
end

Gemfile

source 'https://rubygems.org/'

gem 'nokogiri'
gem 'execjs'
gem 'em-synchrony'
gem 'em-http-request'