套接字服务器和客户端在相同的python脚本中

Question

The below code does not work, when I keep both socket server and client code in the same script file where I run server in the main thread and the client in a separate thread using start_new_thread

import socket, sys
from thread import *

host = socket.gethostname()
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
try:
    s.bind((host, 8888))
except socket.error as msg:
    print 'Bind failed. Error Code : ' + str(msg[0]) + ' Message ' + msg[1]
    sys.exit()
s.listen(10)

def clientthread(conn):
    conn.send('Welcome to the server. Type something and hit enter\n')
    while True:
        data = conn.recv(1024)
        reply = 'OK...' + data
        if not data:
            break
        conn.sendall(reply)
    conn.close()

while 1:
    conn, addr = s.accept()
    print 'Connected with ' + addr[0] + ':' + str(addr[1])
    start_new_thread(clientthread ,(conn,))
s.close()

Answer 1

If you bind() to your gethostname() , you also have to connect to that interface from the client, even if it is on the same computer. "localhost" or "127.0.0.1" will not work. If you want them to work, either bind() to them directly, or bind to everything ( "0.0.0.0" or just an empty string, "" ).

Low-budget test code:

from _thread import *
import socket,time

def client():
    print("Thread starts")
    time.sleep(1)
    print("Thread connects")
    sock=socket.create_connection((socket.gethostname(),8888))
    #sock=socket.create_connection(("localhost",8888))
    print("Thread after connect")
    sock.sendall(b"Hello from client")
    sock.close()
    print("Thread ends")

serv=socket.socket()
serv.bind((socket.gethostname(),8888))
#serv.bind(("localhost",8888))
#serv.bind(("0.0.0.0",8888))
#serv.bind(("",8888))
serv.listen(10)
start_new_thread(client,())
print("Before accept")
s,c=serv.accept()
print("After accept "+c[0])
print("Message: "+s.recv(1024).decode("ASCII"))
s.close()
serv.close()

Feel free to experiment with testing the various sock+bind combinations.