server.py

#!/usr/bin/env python3

# This wrapper turns off the Python HTTP server's overly aggressive
# cache headers, which can get in the way of Verso hovers.

from http import server # Python 3
from http.server import ThreadingHTTPServer, test
import os


class NonCachingHTTPRequestHandler(server.SimpleHTTPRequestHandler):
    def end_headers(self):
        self.send_my_headers()
        server.SimpleHTTPRequestHandler.end_headers(self)

    def send_my_headers(self):
        self.send_header("Cache-Control", "no-cache, no-store, must-revalidate")
        self.send_header("Pragma", "no-cache")
        self.send_header("Expires", "0")

if __name__ == '__main__':
    import argparse
    import contextlib

    parser = argparse.ArgumentParser()
    parser.add_argument('-b', '--bind', metavar='ADDRESS',
                        help='bind to this address '
                             '(default: all interfaces)')
    parser.add_argument('-d', '--directory', default="_out/html-multi",
                        help='serve this directory '
                             '(default: _out/html-multi)')
    parser.add_argument('-p', '--protocol', metavar='VERSION',
                        default='HTTP/1.0',
                        help='conform to this HTTP version '
                             '(default: %(default)s)')
    parser.add_argument('port', default=8000, type=int, nargs='?',
                        help='bind to this port '
                             '(default: %(default)s)')
    args = parser.parse_args()

    # ensure dual-stack is not disabled; ref #38907
    class DualStackServer(ThreadingHTTPServer):

        def server_bind(self):
            # suppress exception when protocol is IPv4
            with contextlib.suppress(Exception):
                self.socket.setsockopt(
                    socket.IPPROTO_IPV6, socket.IPV6_V6ONLY, 0)
            return super().server_bind()

        def finish_request(self, request, client_address):
            self.RequestHandlerClass(request, client_address, self,
                                     directory=args.directory)

    print(args)

    test(
        HandlerClass=NonCachingHTTPRequestHandler,
        ServerClass=DualStackServer,
        port=args.port,
        bind=args.bind,
        protocol=args.protocol,
    )