module Sinatra::Helpers

def send_file(path, opts={})
  stat = File.stat(path)
  last_modified stat.mtime
  if opts[:type] or not response['Content-Type']
    content_type opts[:type] || File.extname(path), :default => 'application/octet-stream'
  end
  if opts[:disposition] == 'attachment' || opts[:filename]
    attachment opts[:filename] || path
  elsif opts[:disposition] == 'inline'
    response['Content-Disposition'] = 'inline'
  end
  file_length = opts[:length] || stat.size
  sf = StaticFile.open(path, 'rb')
  if ! sf.parse_ranges(env, file_length)
    response['Content-Range'] = "bytes */#{file_length}"
    halt 416
  elsif r=sf.range
    response['Content-Range'] = "bytes #{r.begin}-#{r.end}/#{file_length}"
    response['Content-Length'] = (r.end - r.begin + 1).to_s
    halt 206, sf
  else
    response['Content-Length'] ||= file_length.to_s
    halt sf
  end
rescue Errno::ENOENT
  not_found
end