【Python Network】getaddrinfo处理Family参数

本实例通过命令行取得主机和端口的信息，使用SOCK_STREAM请求一个TCP socket。使用AF_INET或AF_INET6指定协议，但本实例并不指定协议，而是通过查询匹配得出适用的协议。

#! /usr/bin/env python
# Connect Example with IPv4 Awarness - Chapter 5 - ipv4connect.py

import socket, sys

def getaddrinfo_pref(host, port, socktype, familypreference = socket.AF_INET):
    """Given a host, port and socktype (Usually socket.SOCK_STREAM or 
    socket.SOCK_DGRAM), looks up information with both IPv4 and IPv6. If
    information is found corresponding to the familypreference, it is returned.
    Otherwise, any information found is returned. The family preference defaults
    to IPv4 (socket.AF_INET) but you could also set it to socket.AF_INET6 for IPv6.

    The return value is the appropriate tuple returned from
    socket.getaddrinfo()."""
    
    results = socket.getaddrinfo(host, port, 0, socktype)
    for result in results:
        if result[0] == familypreference:
            return result
    return results[0]

host = sys.argv[1]
port = 'http'

c = getaddrinfo_pref(host, port, socket.SOCK_STREAM)
print "Connecting to ", c[4]
s = socket.socket(c[0], c[1])
s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
s.connect(c[4])
s.sendall("HEAD / HTTP/1.0\r\n\r\n")

while 1:
    buf = s.recv(4096)
    if not len(buf):
        break
    sys.stdout.write(buf)

使用./ipv4connect.py baidu.com运行。截图如下：