progress-bar-test.rb

#!/usr/bin/env ruby
#
# PoC to show bug in ProgressBar/Zlib handling
#
# Joshua J. Drake (jduck)
#

COMPRESSED_WRONG_SIZE_URL = "http://sourceforge.net/projects/pocfiles/files/"

require 'uri'
require 'net/http'
require 'progressbar'

def get_with_bug(url)
  uri = URI.parse(url)
  gr = Net::HTTP::Get.new(uri.request_uri)
  data = ''
  Net::HTTP.start(uri.host, uri.port) { |http|
    http.request(gr) { |res|
      case res.code
      when "200"
        pbar = nil
        len = res['content-length'].to_i
        if len > 0
          puts "expecting #{len} bytes"
          pbar = ProgressBar.new("  Progress", len)
          pbar.file_transfer_mode
        end

        count = 0
        res.read_body { |chunk|
          count += chunk.length
          puts "#{count} / #{len} received"
          if pbar
            pbar.set(count)
          end
          data << chunk
        }
        puts ""
        if (not (data and data.length > 0))
          raise RuntimeError, "Unable to open #{url.to_s}"
        end

      end
    }
  }
  return data
end

def get_without_bug(url)
  uri = URI.parse(url)
  gr = Net::HTTP::Get.new(uri.request_uri)
  data = ''
  Net::HTTP.start(uri.host, uri.port) { |http|
    http.request(gr) { |res|
      case res.code
      when "200"
        pbar = nil
        len = res['content-length'].to_i
        if len > 0
          puts "expecting #{len} bytes"
          pbar = ProgressBar.new("  Progress", len)
          pbar.file_transfer_mode
        end

        count = 0
        res.read_body { |chunk|
          count += chunk.length
          puts "#{count} / #{len} received"
          if pbar
            pbar.set(count) rescue nil
          end
          data << chunk
        }
        puts ""
        if (not (data and data.length > 0))
          raise RuntimeError, "Unable to open #{url.to_s}"
        end

      end
    }
  }
  return data
end

data = get_without_bug(COMPRESSED_WRONG_SIZE_URL)
puts "without bug, we got #{data.length} bytes"

data = get_with_bug(COMPRESSED_WRONG_SIZE_URL)
puts "with bug, we got #{data.length} bytes"