Grab some pony gifs

grab.rb

#!/usr/bin/env ruby

require "optparse"
require "ostruct"
require "nokogiri"
require "uri"
require "open-uri"
require "net/http"

options = OpenStruct.new
OptionParser.new do |opts|
  opts.banner = "Usage: grab.rb [options] \n" +
                "Image grabber for the 200 gifs for 100 days MLP thread"

  options.target_dir = Dir.getwd
  opts.on("--target-dir DIRECTORY", "The output directory, defaults to the current directory") do |dir|
    # maybe we are given a directory relative to our working dir?
    dir = File.join(Dir.getwd, dir) unless Dir.exists?(dir)
    fail "No such directory: #{dir}" unless Dir.exists?(dir)
    options.target_dir = dir
  end

  opts.on("-o", "--overwrite", "Overwrite existing files") do |overwrite|
    options.overwrite = true
  end

  opts.on("-n", "--no-separate-folders", "Do not create separate folders for the different seasons and the bonus gifs") do |no_separate_folders|
    options.no_separate_folders = true
  end
  options.separate_folders = {
    :season => "Season%02d",
    :bonus => "Bonus",
  }

  options.url = "http://www.reddit.com/r/mylittlepony/comments/1ki386/200_gifs_for_100_days_a_gif_retrospective_of_mlp/"
  opts.on("--url URL", "Url to use to grab the images, defaults to '#{options.url}'") do |url|
    options.url = url
  end

  options.selector = ".expando a, .id-t1_cc09ygp > .entry .usertext-body a"
  opts.on("--selector SELECTOR", "The link selector to use, defaults to '#{options.selector}'") do |selector|
    options.selector = selector
  end

  options.bonus_selector = ".id-t1_ccwgi0x > .entry .usertext-body a, .id-t1_ccwgiew > .entry .usertext-body a, .id-t1_cdi7vmy > .entry .usertext-body a"
  opts.on("--bonus-selector SELECTOR", "The link selector to use, defaults to '#{options.bonus_selector}'") do |bonus_selector|
    options.bonus_selector = bonus_selector
  end
end.parse!


links = []
Nokogiri::HTML(open(options.url)).css(options.selector, options.bonus_selector).each do |link|
  links << { text: link.text, uri: link["href"] } if link["href"].match(/\.gif\z/)
end

$bonus_name_counter = 0
def filename_from_text(text, ext, options)
  filename = text.strip.gsub(' ', '-').gsub(/[^\w-]/, '') + ext
  unless filename.match(/\AS\d{2}E\d{2}/i)
    filename = "Bonus-%03d-%s" % [$bonus_name_counter+=1, filename]
  end

  unless options.no_separate_folders
    case filename
    when /\AS(\d{2})/i
      filename = File.join(options.separate_folders[:season] % Regexp.last_match(1), filename)
    when /\ABonus/i
      filename = File.join(options.separate_folders[:bonus], filename)
    end
  end

  filename
end

links.each_with_index do |link, i|
  print "Downloading %03d of %03d \"%s\"                                                                          \r" % [i+1, links.size, link[:text]]

  uri = URI::Parser.new.parse(link[:uri])
  Net::HTTP.start(uri.host) do |http|
    filename = File.join(options.target_dir, filename_from_text(link[:text], File.extname(uri.path), options))
    Dir.mkdir(File.dirname(filename)) unless Dir.exists?(File.dirname(filename))
    File.open(filename, "wb") do |f|
      http.request_get(uri.path) do |response|
        response.read_body do |segment|
          f.write(segment)
        end
      end
    end if !File.size?(filename) || options.overwrite
  end
end