Boston Key Party CTF

OptiProxy.rb

require 'nokogiri'
require 'open-uri'
require 'sinatra'
require 'shellwords'
require 'base64'
require 'fileutils'

set :bind, "0.0.0.0"
set :port, 5300
cdir = Dir.pwd
get '/' do
        str = "welcome to the automatic resource inliner, we inline all images"
        str << " go to /example.com to get an inlined version of example.com"
        str << " flag is in /flag"
        str << " source is in /source"
        str
end

get '/source' do
        IO.read "/home/optiproxy/optiproxy.rb"
end

get '/flag' do
        str = "I mean, /flag on the file system... If you're looking here, I question"
        str << " your skills"
        str
end

get '/:url' do
        url = params[:url]
        main_dir = Dir.pwd
        temp_dir = ""
        dir = Dir.mktmpdir "inliner"
        Dir.chdir dir
        temp_dir = dir
        exec = "timeout 5 wget -T 2 --page-requisites #{Shellwords.shellescape url}"
        `#{exec}`
        my_dir = Dir.glob ("**/")
        Dir.chdir my_dir[0]
        index_file = "index.html"
        html_file = IO.read index_file
        doc = Nokogiri::HTML(open(index_file))
        doc.xpath('//img').each do |img|
                header = img.xpath('preceding::h2[1]').text
                image = img['src']
                img_data = ""
                uri_scheme = URI(image).scheme
                begin
                        if (uri_scheme == "http" or uri_scheme == "https")
                                url = image
                        else
                                url = "http://#{url}/#{image}"
                        end
                        img_data = open(url).read
                        b64d = "data:image/png;base64," + Base64.strict_encode64(img_data)
                        img['src'] = b64d
                rescue
                        # gotta catch 'em all
                        puts "lole"
                        next
                end
        end
        puts dir
        FileUtils.rm_rf dir
        Dir.chdir main_dir
        doc.to_html
end