require 'net/http'

# WARNING do not use this; it works but is very limited
def resolve url
  res = Net::HTTP.get_response URI(url)
  if res.code == '301' then res['location']
  else url.to_s
  end
end

# Why the above method sucks:
# - doesn't handle multiple redirects
# - uses HTTP GET instead of HEAD (slower, wasted bandwidth)
# - no HTTP error and Ruby exception handling
# - no HTTPS support
# - no strict timeouts (lookups can block for too long)