Python:必须按 ctrl+c 才能得到结果

Question

我正在尝试创建一个 python 脚本来检查端口是否可用。下面是一段代码(不是整个脚本)。

但是当我运行脚本时，终端没有显示任何输出，当我按 ctrl + c 时，我得到脚本的单个结果，当我再次按 ctrl+c 时，我得到第二个结果。当脚本完成后，它最终退出......

#!/usr/bin/python

import re
import socket
from itertools import islice

resultslocation = '/tmp/'
f2name = 'positives.txt'
f3name = 'ip_addresses.txt'
f4name = 'common_ports.txt'

#Trim down the positive results to only the IP addresses and scan them with the given ports in the common_ports.txt file

with open(resultslocation + f2name, 'r') as f2, open(resultslocation + f3name, 'w') as f3:
    hits = f2.read()
    list = re.findall(r'name = (.+).', hits)
    for items in list:
        ip_addresses = socket.gethostbyname(items)
        with open(resultslocation + f4name, 'r') as f4:
            for items in f4:
                ports = int(items)
                s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
                try:
                    s.connect((ip_addresses, ports))
                    s.shutdown(2)
                    print 'port', ports, 'on', ip_addresses, 'is open'
                except:
                    print 'port', ports, 'on', ip_addresses, 'is closed'

我做错了什么？

提前致谢!

Answer 1

默认情况下，套接字以阻塞模式创建。

因此，一般情况下，建议在调用 connect() 之前调用 settimeout() 或将超时参数传递给 create_connection() 并使用它而不是连接。由于您的代码已经捕获了异常，因此第一个选项很容易实现；

with open(resultslocation + f2name, 'r') as f2, open(resultslocation + f3name, 'w') as f3:
    hits = f2.read()
    list = re.findall(r'name = (.+).', hits)
    for items in list:
        ip_addresses = socket.gethostbyname(items)
        with open(resultslocation + f4name, 'r') as f4:
            for items in f4:
                ports = int(items)
                s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
                s.settimeout(1.0) # Set a timeout (value in seconds).
                try:
                    s.connect((ip_addresses, ports))
                    s.shutdown(2)
                    print 'port', ports, 'on', ip_addresses, 'is open'
                except:
                    # This will alse catch the timeout exception.
                    print 'port', ports, 'on', ip_addresses, 'is closed'