错误 - 全局名称 'SOL_SOCKET' 未定义

Question

我正在尝试创建一个基本的即时消息程序，这个程序使用点对点（p2p）连接，所以不需要服务器。我觉得我的代码应该没问题，但每次运行我写的客户端程序时，都会出现这个错误：

s.setsockopt(SOL_SOCKET, SO_REUSEADDR, 1) NameError: global name 'SOL_SOCKET' is not defined

这是我的程序：

import socket

def Receiver():

    # Create socket that supports IPv4, TCP Protocol
    s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    print "Socket created."
    # Requests for IP of host (DNS)
    dns = "localhost"
    HOST = ''
    PORT = 25395
    try:

        s.setsockopt(SOL_SOCKET, SO_REUSEADDR, 1)
    except socket.error as serror:
        print "socket error"
    s.bind((HOST, PORT)) # Listens on all interfaces...
    print 'Listening on port 25565'
    s.listen(True) # Listen on the newly created socket... 
    conn, addr = s.accept()
    print 'Connected in port 25565'
    data = conn.recv(1024)
    print data
    s.close()
def Sender():

    s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    dns = "localhost"
    HOST = socket.gethostbyname(dns)
    port = 25565    
    # Connect to server
    s.connect((host,port))

    print "Socket connected to " + dns + " on IP " + host

    # Assign message to be sent to server to a variable
    message = raw_input("Message to be sent to server: ")

    #Send the actual message to server
    s.sendall(message)
    print "Message sent successfully"
    s.close()


input = raw_input('S is send, R is receive: ')
if input == 's':
    Sender()
if input == 'r':
    Receiver()

我试过去掉 s.setsockopt(SOL_SOCKET, SO_REUSEADDR, 1) 这行代码，但它告诉我不能在同一个端口上使用两个套接字，而实际上并没有两个套接字在使用同一个端口。

Answer 1

在你的代码中：

 s.setsockopt(SOL_SOCKET, SO_REUSEADDR, 1)

可以这样做：

 s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
  #            ^^^^ added         ^^^

因为你只导入了 socket，请查看以下代码片段：

>>> import socket
>>> SOL_SOCKET
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
NameError: name 'SOL_SOCKET' is not defined
>>> socket.SOL_SOCKET
1