如何在套接字编程聊天应用程序中实现线程

Question

所以我还包括代码的服务器端，但客户端的问题。这是一个简单的 TCP 客户端套接字代码。问题是在第 21 行，在第一个 while 循环之后（我还在代码中注释了我所指的地方），我要求用户输入。

然后发生的情况是，当更多用户连接时，任何用户的聊天屏幕都不会更新，除非他们按下回车键，如您所见，只有在向“消息”变量提供输入后才会继续。

现在我知道线程需要在这里完成，但我并没有真正获得足够的相关知识。因此，如果有人可以指导我或帮助我修改代码，以便无需输入即可更新聊天。

Cient 代码（第 21 行的问题，在第一个 while 循环之后...已注释）

from socket import *
import select
import errno
import sys

header_length = 10
ip = "127.0.0.1"
port = 1234

my_username = input("Username: ")
client_socket = socket(AF_INET, SOCK_STREAM)
client_socket.connect((ip, port))
client_socket.setblocking(False)

username = my_username.encode()
username_header = f"{len(username):<{header_length}}".encode()
client_socket.send(username_header + username)

while True:
    #Where my issue is
    message = input(f"{my_username} > ")

    if message:
        message = message.encode()
        message_header = f"{len(message):<{header_length}}".encode()
        client_socket.send(message_header + message)
        
    try:
        while True:
            #receive messages
            username_header = client_socket.recv(header_length)
            if not len(username_header):
                print("Connection closed by the server...")
                sys.exit()
            
            username_length = int(username_header.decode().strip())
            username = client_socket.recv(username_length).decode()

            message_header = client_socket.recv(header_length)
            message_length = int(message_header.decode().strip())
            message = client_socket.recv(message_length).decode()

            print(f"{username} > {message}")

    except IOError as e:
        if e.errno != errno.EAGAIN and e.errno != errno.EWOULDBLOCK:
            print("Reading error: ", str(e))
            sys.exit()
        continue

    except Exception as e:
        print("General error: ", str(e))
        sys.exit()

服务器代码（如果有人需要）：

from socket import *
import select

header_length = 10
ip = "127.0.0.1"
port =  1234

server_socket = socket(AF_INET, SOCK_STREAM)
server_socket.setsockopt(SOL_SOCKET, SO_REUSEADDR, 1)

server_socket.bind((ip, port))
server_socket.listen()
 
socket_list = [server_socket]
clients = {}


#Handles message receiving
def recieve_message(client_socket):
    try:
        message_header = client_socket.recv(header_length)

        if not len(message_header):
            return False
        
        message_length = int(message_header.decode().strip())
        return {'header': message_header, 'data': client_socket.recv(message_length)}

    except:
        return False


print(f'Listening for connections on {ip}:{port}...')

while True:
    read_sockets, _, exception_sockets = select.select(socket_list, [], socket_list)

    for notified_socket in read_sockets:
        if notified_socket == server_socket:
            client_socket, client_address = server_socket.accept()
            user = recieve_message(client_socket)

            if user is False:
                continue

            socket_list.append(client_socket)
            clients[client_socket] = user
            print(f"Accepted new connection from {client_address[0]}:{client_address[1]} username:{user['data'].decode()}")
        
        else:
            message = recieve_message(notified_socket)

            if message is False:
                print(f"Closed connection from {clients[notified_socket]['data'].decode()}")
                socket_list.remove(notified_socket)
                del clients[notified_socket]
                continue

            user = clients[notified_socket]
            print(f"Recieved messasge from {user['data'].decode()}: {message['data'].decode()}")

            for client_socket in clients:
                if client_socket != notified_socket:
                    client_socket.send(user['header'] + user['data'] + message['header'] + message['data'])                
    
    for notified_socket in exception_sockets:
        socket_list.remove(notified_socket)
        del clients[notified_socket]

我还包含了图像...正如您所见，当我在客户端 1 的窗口中输入 hello 时，客户端 2 没有显示它。直到我输入一些东西并按回车后才会这样做

非常感谢:)

Answer 1

为什么不像 服务器 那样将select.select 用于客户端？ 效果很好。

Linux 版本

from socket import *
import select
import errno
import sys


def prompt(username):
    sys.stdout.write(f"{username} > ")
    sys.stdout.flush()


header_length = 10
ip = "127.0.0.1"
port = 1234

my_username = input("Username: ")
client_socket = socket(AF_INET, SOCK_STREAM)
client_socket.connect((ip, port))
client_socket.setblocking(False)

username = my_username.encode()
username_header = f"{len(username):<{header_length}}".encode()
client_socket.send(username_header + username)

while True:
    socket_list = [sys.stdin, client_socket]
    prompt(my_username)

    read_sockets, write_sockets, error_sockets = select.select(socket_list, [], [])
    for socket in read_sockets:
        try:
            if socket == sys.stdin:
                message = sys.stdin.readline()
                message = message.encode()
                message_header = f"{len(message):<{header_length}}".encode()
                client_socket.send(message_header + message)
            elif socket == client_socket:
                username_header = client_socket.recv(header_length)
                if not len(username_header):
                    print("Connection closed by the server...")
                    sys.exit()

                username_length = int(username_header.decode().strip())
                username = client_socket.recv(username_length).decode()
                message_header = client_socket.recv(header_length)
                message_length = int(message_header.decode().strip())
                message = client_socket.recv(message_length).decode()
                print(f"\n{username} > {message}")

        except IOError as e:
            if e.errno != errno.EAGAIN and e.errno != errno.EWOULDBLOCK:
                print("Reading error: ", str(e))
                sys.exit()
            continue
        except Exception as e:
            print("General error: ", str(e))
            sys.exit()

Windows/Linux 版本（由于select 限制）

注意： Windows 上的文件对象是不可接受的，但套接字是。在 Windows 上， 底层的 select() 函数由 WinSock 库提供，并不 处理并非源自 WinSock 的文件描述符。

import threading
from socket import *
import select
import errno
import sys


def prompt(username):
    sys.stdout.write(f"{username} > ")
    sys.stdout.flush()


def redirect_sdtin(dest):
    for ln in sys.stdin:
        dest.send(ln.encode())


header_length = 10
ip = "127.0.0.1"
port = 1234

my_username = input("Username: ")
stdin_in, stdin_out = socketpair()
threading.Thread(target=redirect_sdtin, args=(stdin_in,), daemon=True).start()

client_socket = socket(AF_INET, SOCK_STREAM)
client_socket.connect((ip, port))
client_socket.setblocking(False)

username = my_username.encode()
username_header = f"{len(username):<{header_length}}".encode()
client_socket.send(username_header + username)

while True:
    socket_list = [stdin_out, client_socket]
    prompt(my_username)

    read_sockets, write_sockets, error_sockets = select.select(socket_list, [], [])
    for socket in read_sockets:
        try:
            if socket == stdin_out:
                message = stdin_out.recv(1024)
                message_header = f"{len(message):<{header_length}}".encode()
                client_socket.send(message_header + message)
            elif socket == client_socket:
                username_header = client_socket.recv(header_length)
                if not len(username_header):
                    print("Connection closed by the server...")
                    sys.exit()

                username_length = int(username_header.decode().strip())
                username = client_socket.recv(username_length).decode()
                message_header = client_socket.recv(header_length)
                message_length = int(message_header.decode().strip())
                message = client_socket.recv(message_length).decode()
                print(f"\n{username} > {message}")

        except IOError as e:
            if e.errno != errno.EAGAIN and e.errno != errno.EWOULDBLOCK:
                print("Reading error: ", str(e))
                sys.exit()
            continue
        except Exception as e:
            print("General error: ", str(e))
            sys.exit()