Simple Python3 webserver with custom POST handler

server.py

import sys, os, cgi, _thread
from http.server import SimpleHTTPRequestHandler, HTTPServer

class MyServer(SimpleHTTPRequestHandler):
  #Custom POST handler that saves POSTed file content to local disk
  def do_POST(self):
    post_env = { 
      'REQUEST_METHOD': 'POST',
      'CONTENT_TYPE': self.headers['Content-Type'],
    }   
    form = cgi.FieldStorage(fp=self.rfile, headers=self.headers, environ=post_env)
    if 'file' in form: _thread.start_new_thread(save_file, (form['file'],))
        
    content_len = int(self.headers['Content-Length'])

    self.send_response(200)
    self.send_header('Content-type', 'text/html')
    self.send_header('Content-length', 0)
    self.end_headers()
    self.wfile.write(''.encode('utf-8'))

#Threaded function
def save_file(f):
  with open(f.filename, 'wb') as fp: fp.write(f.file.read())
  print('Saved ' + f.filename)

if __name__ == "__main__":
  PORT = int(sys.argv[1])
  HOSTNAME = '0.0.0.0'

  server = HTTPServer((HOSTNAME, PORT), MyServer)

  try:
    server.serve_forever()
  except KeyboardInterrupt:
    pass

  server.server_close()