xenu_nntp/lib/nntp/tiny/server.py

import re
import enum
import threading
import socket
import selectors
import ssl

from nntp.tiny.config  import Config, ConfigException
from nntp.tiny.db      import Database
from nntp.tiny.host    import Host
from nntp.tiny.session import Session

class Server():
    def __init__(self, config: Config):
        self.config = config
        self.sslctx = None

        if config.section('listen').get('tls', 'no') == 'yes':
            self.sslctx = ssl.SSLContext(ssl.PROTOCOL_TLS_SERVER)
            self.sslctx.load_cert_chain(config.get('tls', 'cert'),
                                        config.get('tls', 'key'))

    def connect_to_db(self):
        return Database.connect(self.config.get('database', 'path'))

    def listen(self, host: str, port: int, af: int):
        listener = socket.socket(af, socket.SOCK_STREAM)
        listener.bind((host, port))
        listener.listen()

        if self.sslctx:
            return self.sslctx.wrap_socket(listener, server_side=True)

        return listener

    def accept(self, listener):
        sock, addr = None, None

        try:
            sock, addr = listener.accept()
        except ssl.SSLError as e:
            return

        def spawn():
            session = Session(self, sock)

            try:
                session.handle()
            except (ssl.SSLEOFError, ssl.SSLError):
                pass

        thread = threading.Thread(target=spawn)
        thread.start()

    def run(self):
        hosts = re.split(r'\s*,\s*', self.config.get('listen', 'host'))
        port  = int(self.config.get('listen', 'port'))

        listeners = list()

        for host in hosts:
            if Host.is_ipv6(host):
                listeners.append(self.listen(host, port, socket.AF_INET6))
            elif Host.is_ipv4(host):
                listeners.append(self.listen(host, port, socket.AF_INET))
            else:
                for af in (socket.AF_INET, socket.AF_INET6):
                    listeners.append(self.listen(host, port, af))

        if len(listeners) == 0:
            raise ConfigException('No listener hosts specified')

        sel = selectors.DefaultSelector()

        for listener in listeners:
            sel.register(listener, selectors.EVENT_READ)

        while True:
            events = sel.select()

            for key, ev in events:
                self.accept(key.fileobj)

    def stop(self):
        ...