internet-delay-chat/servers/py-trio-struct/idc.py

#!/usr/bin/env python3
#
# Internet Delay Chat server written in Python Trio.
#
# Written by: Andrew <https://www.andrewyu.org>
#             luk3yx <https://luk3yx.github.io>
#
# This is free and unencumbered software released into the public
# domain.
#
# Anyone is free to copy, modify, publish, use, compile, sell, or
# distribute this software, either in source code form or as a compiled
# binary, for any purpose, commercial or non-commercial, and by any
# means.
#
# In jurisdictions that recognize copyright laws, the author or authors
# of this software dedicate any and all copyright interest in the
# software to the public domain. We make this dedication for the benefit
# of the public at large and to the detriment of our heirs and
# successors. We intend this dedication to be an overt act of
# relinquishment in perpetuity of all present and future rights to this
# software under copyright law.
#
# 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 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.
#
# This program requires Python 3.9 or later due to its extensive use of
# type annotations.  Usage with an older version would likely cause
# SyntaxErrors.  If mypy has problems detecting types on the Trio
# library, install trio-typing.  Please mypy after every runnable edit.
#

from __future__ import annotations
from typing import Awaitable, Callable
import time

from pprint import pprint

import trio
import ssl
import traceback

import exceptions
import entities
import minilog
import utils
import config

starttime = time.time()

PORT = 6835

ctx = ssl.SSLContext(ssl.PROTOCOL_TLS_SERVER)
ctx.load_cert_chain(
    "/etc/letsencrypt/live/fcm.andrewyu.org/fullchain.pem",
    "/etc/letsencrypt/live/fcm.andrewyu.org/privkey.pem",
)

client_id_counter = -1
local_users: dict[bytes, entities.User] = {}
local_channels: dict[bytes, entities.Channel] = {}

for username in config.users:
    local_users[username] = entities.User(
        username=username,
        password=config.users[username]["password"],
        options=config.users[username]["options"],
    )

for channelname in config.channels:
    local_channels[channelname] = entities.Channel(
        channelname=channelname,
        broadcast_to=[
            local_users[username]
            for username in config.channels[channelname]["broadcast_to"]
        ],
        guild=None,
    )
    for u in local_channels[channelname].broadcast_to:
        u.in_channels.append(local_channels[channelname])


_CMD_HANDLER = Callable[
    [entities.Client, "dict[str, bytes]"], Awaitable[None]
]
_registered_commands: dict[bytes, _CMD_HANDLER] = {}


def register_command(
    command: str,
) -> Callable[[_CMD_HANDLER], _CMD_HANDLER]:
    def register_inner(func: _CMD_HANDLER) -> _CMD_HANDLER:
        _registered_commands[command.encode("ascii")] = func
        return func

    return register_inner


@register_command("HELP")
async def _help_cmd(
    client: entities.Client, args: dict[str, bytes]
) -> None:
    await utils.send(
        client,
        b"HELP",
        AVAILABLE_COMMANDS=b" ".join(_registered_commands),
    )


@register_command("LOGIN")
async def _login_cmd(
    client: entities.Client, args: dict[str, bytes]
) -> None:
    if client.user:
        raise exceptions.AlreadyLoggedIn(
            b"You are already logged in as "
            + client.user.username
            + b"."
        )

    attempting_username = utils.carg(args, "USERNAME", b"LOGIN")
    attempting_password = utils.carg(args, "PASSWORD", b"LOGIN")
    try:
        if (
            local_users[attempting_username].password
            == attempting_password
        ):
            client.user = local_users[attempting_username]
            local_users[attempting_username].connected_clients.append(
                client
            )
            await utils.send(
                client,
                b"LOGIN_GOOD",
                USERNAME=attempting_username,
                COMMENT=b"Login is good.",
            )
            assert client.user is not None
            for c in client.user.in_channels:
                await utils.send(
                    client,
                    b"JOIN",
                    CHANNEL=c.channelname,
                    USERS=b" ".join(
                        [u.username for u in c.broadcast_to]
                    ),
                )
            await utils.send(
                client,
                b"END_BURST",
                COMMENT=b"I'm finished telling you the state you're in.",
            )
            if client.user.queue:
                for i in range(len(client.user.queue)):
                    b = client.user.queue.pop(0)
                    # Do not pop "i" here, because we're modifying the
                    # iterated object within the iteration, so the
                    # indexes change!  Therefore pop 0.
                    await utils.quote(client, b)
            await utils.send(
                client,
                b"END_OFFLINE_MESSAGES",
                COMMENT=b"I'm finished telling you your offline messages.",
            )
        else:
            raise exceptions.LoginFailed(
                b"Invalid password for " + attempting_username + b"."
            )
    except KeyError:
        raise exceptions.LoginFailed(
            attempting_username + b" is not a registered username."
        )


@register_command("PING")
async def _ping_cmd(
    client: entities.Client, args: dict[str, bytes]
) -> None:
    await utils.send(client, b"PONG", COOKIE=utils.carg(args, "COOKIE"))


@register_command("EGG")
async def _egg_cmd(
    client: entities.Client, args: dict[str, bytes]
) -> None:
    await utils.send(
        client,
        b"EASTER_EGG",
        YAY=b"Andrew: Never gonna give you up\nnever gonna let you down\nnever gonna run around and desert you\nnever gonna make you cry\nnever gonna say goodbye\nnever gonna tell a lie and hurt you",
    )


@register_command("PRIVMSG")
async def _privmsg_cmd(
    client: entities.Client, args: dict[str, bytes]
) -> None:  # in the future this should return the raw line sent to the target client
    if not client.user:
        raise exceptions.NotLoggedIn(
            b"You can't use PRIVMSG before logging in!"
        )
    else:
        target_name = utils.carg(args, "TARGET")
        try:
            target_user = local_users[target_name]
        except KeyError:
            raise exceptions.NonexistantTargetError(
                b"The target " + target_name + b" is nonexistant."
            )
        else:
            await utils.send(
                target_user,
                b"PRIVMSG",
                SOURCE=client.user.username,
                TYPE=args.get("TYPE", b"NORMAL"),
                TARGET=utils.carg(args, "TARGET"),
                MESSAGE=utils.carg(args, "MESSAGE"),
            )
            if target_user is not client.user:
                await utils.send(
                    client.user,
                    b"PRIVMSG",
                    SOURCE=client.user.username,
                    TYPE=args.get("TYPE", b"NORMAL"),
                    TARGET=utils.carg(args, "TARGET"),
                    MESSAGE=utils.carg(args, "MESSAGE"),
                )
        # Do you think that we should put echo-message here, or in utils.send()?


@register_command("CHANMSG")
async def _chanmsg_cmd(
    client: entities.Client, args: dict[str, bytes]
) -> None:
    if not client.user:
        raise exceptions.NotLoggedIn(
            b"You can't use CHANMSG before logging in!"
        )
    else:
        target_channel_name = utils.carg(args, "TARGET")
        try:
            target_channel = local_channels[target_channel_name]
        except KeyError:
            raise exceptions.NonexistantTargetError(
                b"The target channel "
                + target_channel_name
                + b"is nonexistant."
            )
        else:

            await utils.send(
                target_channel,
                b"CHANMSG",
                SOURCE=client.user.username,
                TYPE=args.get("TYPE", b"NORMAL"),
                TARGET=target_channel_name,
                MESSAGE=utils.carg(args, "MESSAGE"),
            )


#             await utils.send(
#                 client.user,
#                 b"CHANMSG",
#                 source=client.user.username,
#                 target=target_channel_name,
#                 message=utils.carg(args, "MESSAGE"),
#             )


async def connection_loop(stream: trio.SSLStream) -> None:
    global client_id_counter
    client_id_counter += 1
    ident = str(client_id_counter).encode("ascii")
    minilog.note(f"Connection {str(ident)} has started.")
    client = entities.Client(cid=ident, stream=stream)
    await utils.send(client, b"MOTD", MESSAGE=config.motd)
    client.ccrt = stream.getpeercert()
    await utils.send(client, b"CLIENT_CERT", FINGERPRINT=repr(client.ccrt).encode("utf-8"))
    try:
        msg = b""
        async for newmsg in stream:
            msg += newmsg
            split_msg = msg.split(b"\n")
            if split_msg[-1] == b"\r":
                split_msg = split_msg[:-1]
            if len(split_msg) < 2:
                continue
            data = split_msg[0:-1]
            msg = split_msg[-1]
            minilog.debug(f"{ident.decode('ascii')} >>> {data!r}")
            for cmdline in data:
                try:
                    cmd, args = utils.bytesToStd(cmdline)
                    cmd = cmd.upper()
                    if cmd in _registered_commands:
                        await _registered_commands[cmd](client, args)
                    else:
                        raise exceptions.UnknownCommand(
                            cmd + b" is an unknown command."
                        )
                except exceptions.IDCUserCausedException as e:
                    await utils.send(
                        client,
                        e.severity,
                        PROBLEM=e.error_type,
                        COMMENT=e.args[0],
                    )
    except Exception as exc:
        traceback.print_exc()
        minilog.warning(f"{ident!r}: crashed: {exc!r}")
    finally:
        if client.user:
            client.user.connected_clients.remove(client)
        del client.stream
        del client
        minilog.note(f"Connection {str(ident)} has ended.")


async def tls_wrapper(s: trio.SocketStream) -> None:
    try:
        await connection_loop(trio.SSLStream(s, ctx, server_side=True))
    except trio.BrokenResourceError:
        minilog.caution("Some client has messed-up TLS.")


async def main() -> None:
    await trio.serve_tcp(tls_wrapper, PORT)


def run_i_guess() -> None:
    trio.run(main)


if __name__ == "__main__":
    try:
        minilog.note("Definitions complete.  Establishing listener.")
        trio.run(main)
    except KeyboardInterrupt:
        minilog.error("KeyboardInterrupt!")
    finally:
        minilog.note(
            f"I've ran for {str(time.time() - starttime)} seconds!"
        )