Simple Python3 (HTTPs) Server for a static website, including security headers for A+ rating

server.py

"""
Copyright (c) 2021 1-2.dev
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
"""

from http.server import HTTPServer, SimpleHTTPRequestHandler

# Config
WWW_DIR = '/var/www/html'
HOST = '0.0.0.0'
PORT = 80


# Generate self signed certificate using openssl command
def generate_self_signed_cert():
    import os

    try:
        command = 'openssl req -newkey rsa:4096 -x509 -sha256 -days 3650 -nodes -out cert.pem -keyout key.pem -subj ' \
                  '"/CN=*" '
        os.system(command)
        print('<<<<Certificate Generated>>>>>>')
    except OSError:
        print('Error while generating certificate.')


# Override the Request Handler
class Handler(SimpleHTTPRequestHandler):
    def do_GET(self):
        from pathlib import Path
        import mimetypes

        request_file = self.path

        if request_file == '/':
            request_file = '/index.html'

        request_file = WWW_DIR.rstrip('/') + request_file
        local_path = Path(request_file)

        if local_path.is_file():
            self.send_response(200)
            self.send_header('Content-type', mimetypes.guess_type(request_file)[0])
            self.send_header('Permissions-Policy', 'accelerometer=(), autoplay=(), camera=(), document-domain=(), '
                                                   'encrypted-media=(), fullscreen=(), geolocation=(), gyroscope=(), '
                                                   'magnetometer=(), microphone=(), midi=(), payment=(), '
                                                   'picture-in-picture=(), sync-xhr=(), usb=(), interest-cohort=()')
            self.send_header('Content-Security-Policy', 'upgrade-insecure-requests')
            self.send_header('X-XSS-Protection', '1; mode=block')
            self.send_header('X-Frame-Options', 'SAMEORIGIN')
            self.send_header('X-Content-Type-Options', 'nosniff')
            self.send_header('Referrer-Policy', 'no-referrer')
            self.end_headers()

            with open(request_file, 'rb') as file:
                self.wfile.write(file.read())
        else:
            self.send_response(301)
            self.send_header('Location', '/')
            self.end_headers()


# Start the server
if __name__ == '__main__':
    srv = HTTPServer((HOST, PORT), Handler)

    if PORT == 443 or PORT == 4433 or PORT == 8443:
        import ssl

        generate_self_signed_cert()
        srv.socket = ssl.wrap_socket(srv.socket, keyfile='key.pem', certfile='cert.pem',
                                     server_side=True, ssl_version=ssl.PROTOCOL_TLSv1_2, ca_certs=None,
                                     do_handshake_on_connect=True, suppress_ragged_eofs=True,
                                     ciphers='ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA'
                                             '-AES256-GCM-SHA384:ECDHE-ECDSA-AES256-GCM-SHA384:DHE-RSA-AES128-GCM'
                                             '-SHA256:DHE-DSS-AES128-GCM-SHA256:kEDH+AESGCM:ECDHE-RSA-AES128-SHA256'
                                             ':ECDHE-ECDSA-AES128-SHA256:ECDHE-RSA-AES128-SHA:ECDHE-ECDSA-AES128-SHA'
                                             ':ECDHE-RSA-AES256-SHA384:ECDHE-ECDSA-AES256-SHA384:ECDHE-RSA-AES256-SHA'
                                             ':ECDHE-ECDSA-AES256-SHA:DHE-RSA-AES128-SHA256:DHE-RSA-AES128-SHA:DHE-DSS'
                                             '-AES128-SHA256:DHE-RSA-AES256-SHA256:DHE-DSS-AES256-SHA:DHE-RSA-AES256'
                                             '-SHA:!aNULL:!eNULL:!EXPORT:!DES:!RC4:!3DES:!MD5:!PSK')

    try:
        print('Server started.')
        srv.serve_forever()
    except KeyboardInterrupt:
        pass
    finally:
        srv.server_close()
        print('Server stopped.')