client-hints/echo_ua_client_hints_received.py

def main(request, response):
  """
  Simple handler that sets a response header based on which client hint
  request headers were received.
  """

  response.headers.append("Access-Control-Allow-Origin", "*")
  response.headers.append("Access-Control-Allow-Headers", "*")
  response.headers.append("Access-Control-Expose-Headers", "*")

  client_hint_headers = [
    "sec-ch-ua",
    "sec-ch-ua-arch",
    "sec-ch-ua-platform",
    "sec-ch-ua-model",
  ]

  request_client_hints = {i:request.headers.get(i) for i in client_hint_headers}

  for header in client_hint_headers:
    if request_client_hints[header] is not None:
      response.headers.set(header+"-recieved", request_client_hints[header])

  headers = []
  content = ""
  return 200, headers, content