Python套接字端口使用

Question

I'm trying to set a server application and client application in which the server will listen for connections using localhost and a certain port - however - if for example, the port is 2001 - if that port is not available, I would like to use 2002, if that's not available then 2003 - etc. How do I implement that in my code?

example = socket.socket(socket.AF_INET,socket.SOCK_STREAM)
example.bind(("localhost",2001))

Answer 1

may be just loop around till it doesnt generate an exception

port = 2001
while True:
    try:
        example.bind(("localhost",port))
    except:
        port += 1
        continue
    break

Answer 2

Rather than try to find an available free port in some kind of loop you can bind to port 0 ( zero ) and let your OS bind to a suitable free port. You can then access the bound port via introspecting the server socket object using socket.getsockname()

Answer 3

I prefer to bind the socket to a random port number assigned by the kernel and then query for the port number opened.

example.bind((host,0)) #0-random, free port number
example.getsockname()