Simple HTTP Proxy with Python

#!/usr/bin/python3

import os, sys
# from urllib.parse import urlparse
# from urllib.request import urlopen
import urllib.request

# import cgi
# cgi.print_environ()
path_info = os.environ.get("PATH_INFO", "").lstrip("/")
query_string = os.environ.get("QUERY_STRING", "")


url = "https://"+path_info+"?"+query_string
print ("opening", url, file=sys.stderr)
req = urllib.request.Request(
    url, 
    headers={
        'User-Agent': 'Mozilla/5.0 (Macintosh; Intel Mac OS X 10_9_3) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/35.0.1916.47 Safari/537.36'
    })
f = urllib.request.urlopen(req)
ct = f.info().get("content-type")

print ("Serving data with content-type", ct, file=sys.stderr)
header = ct+"\n\n"
sys.stdout.buffer.write(header.encode("utf-8"))
while True:
    bytes = f.read()
    if bytes:
        sys.stdout.buffer.write(bytes)
    else:
        break

sys.stdout.buffer.flush()

Running (on port 8090)

   python -m http.server 8090 --cgi