Code to download a CSV file on Heroku (using Rails) and run a script on it

File download on Heroku

# I'm using smarter-csv gem to help parse the CSV
require 'net/ftp'

filename = 'filename-here.csv'
temp_file = Tempfile.new("download-#{filename}")
temp_file.binmode
import_options = {chunk_size: 10000, downcase_header: true, :row_sep => :auto, encoding: "UTF-8"}

size = 0
progress = 0

Net::FTP.open('ftp.domain.com') do |ftp|
  ftp.passive = true
  ftp.login 'username', 'password'
  ftp.chdir('/direct-if-there-is-one') 

  total = ftp.size(filename)

  ftp.getbinaryfile(filename, nil, 8192) do |chunk|
    temp_file << chunk
    size += chunk.size
    new_progress = (size * 100) / total
    unless new_progress == progress
      puts "\rDownloading %s (%3d%%) " % [filename, new_progress]
    end
    progress = new_progress
  end
end

SmarterCSV.process(temp_file, import_options) do |chunk|
  chunk.each do |row|
    puts row
  end
end