Python3.5 异步 TCP 扫描器

Question

我是 Python3.5 的新手，除了在 Python 2.7 中少量使用 Twisted 外，我一般都是异步的。我正在将它构建到一个更大的应用程序中，我需要一小部分，而不是一个单一的框架，来执行 TCP 端口扫描。

import asyncio
from random import SystemRandom

def run(task, *, loop=None):
    if loop is None:
        loop = asyncio.get_event_loop()
    return loop.run_until_complete(asyncio.ensure_future(task, loop=loop))

async def scanner(ip, port, loop=None):
    fut = asyncio.open_connection(ip, port, loop=loop)
    try:
        reader, writer = await asyncio.wait_for(fut, timeout=0.5) # This is where it is blocking?
        print("{}:{} Connected".format(ip, port))
    except asyncio.TimeoutError:
        pass

def scan(ips, ports, randomize=False):
    if randomize:
        rdev = SystemRandom()
        ips = rdev.shuffle(ips)
        ports = rdev.shuffle(ports)
    for port in ports:
        for ips in ips:
            run(scanner(ip, port))

 ips = ["192.168.0.{}".format(i) for i in range(1, 255)]
 ports = [22, 80, 443, 8080]
 scan(ips, ports)

这仍然需要与单个线程一样长的时间。我怎样才能把它变成一个异步 TCP 扫描器？

Answer 1

run_until_complete 正在阻塞，执行停止并等待直到第一次扫描结束，然后是下一次...

您应该安排所有（或部分）任务并使用wait 等待所有任务。

import asyncio
from random import SystemRandom

def run(tasks, *, loop=None):
    if loop is None:
        loop = asyncio.get_event_loop()
    # waiting for all tasks
    return loop.run_until_complete(asyncio.wait(tasks))

async def scanner(ip, port, loop=None):
    fut = asyncio.open_connection(ip, port, loop=loop)
    try:
        reader, writer = await asyncio.wait_for(fut, timeout=0.5) # This is where it is blocking?
        print("{}:{} Connected".format(ip, port))
    except asyncio.TimeoutError:
        pass
    # handle connection refused and bunch of others
    except Exception as exc:
        print('Error {}:{} {}'.format(ip, port, exc))

def scan(ips, ports, randomize=False):
    loop = asyncio.get_event_loop()
    if randomize:
        rdev = SystemRandom()
        ips = rdev.shuffle(ips)
        ports = rdev.shuffle(ports)

    # let's pass list of task, not only one
    run([scanner(ip, port) for port in ports for ip in ips])

ips = ["192.168.0.{}".format(i) for i in range(1, 255)]
ports = [22, 80, 443, 8080]
scan(ips, ports)

我还添加了except 块来捕获其余异常，包括最常见的连接被拒绝。