download_progress.rb

#from http://stackoverflow.com/questions/2301009/get-file-size-before-downloading-counting-how-much-already-downloaded-httpru

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

url = "http://ipv4.download.thinkbroadband.com/5MB.zip"

url_base = url.split('/')[2]
url_path = '/'+url.split('/')[3..-1].join('/')
@counter = 0

Net::HTTP.start(url_base) do |http|
  response = http.request_head(URI.escape(url_path))
  ProgressBar
  pbar = ProgressBar.new("file name:", response['content-length'].to_i)
  File.open("test.file", 'w') {|f|
    http.get(URI.escape(url_path)) do |str|
      f.write str
  @counter += str.length 
  pbar.set(@counter)
    end
   }
  pbar.finish
end

puts "Done."

Gemfile

source "https://rubygems.org"

gem "progressbar"

output.log

$ bundle exec ruby download_progress.rb
file name::    100% |oooooooooooooooooooooooooooooooooooooooooooo| Time:   0:00:00
Done.