无法通过Python中的套接字进行客户端 - 服务器通信

Question

在过去的两周里，我一直在反对插座问题，但无济于事。 我有一个12'客户端'机器和一台服务器机器的设置。 服务器被赋予了大量任务，将其分成12个较小的任务，然后将它们分发给12个客户端。 客户流失，一旦完成任务，他们应该让服务器知道他们已经通过套接字通信完成了。 出于某种原因，这只是一点点工作或根本不工作（服务器和客户端，只是坐在while循环中）。

这是服务器上的代码：

socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
socket.bind(('localhost', RandomPort))
socket.listen(0)
socket.settimeout(0.9)

[Give all the clients their tasks, then do the following:]

while 1:
    data = 'None'
    IP = [0,0]   
    try:
        Client, IP = socket.accept()
        data = Client.recv(1024)
        if data == 'Done':
            Client.send('Thanks')
        for ClientIP in ClientIPList():
            if ClientIP == IP[0] and data == 'Done':
                FinishedCount += 1 
            if FinishedCount == 12:
                break
    except:
        pass

以下是所有客户端的代码：

[Receive task from server and execute. Once finished, do the following:]

while 1:
    try:
        f = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
        f.connect((IPofServer, RandomPort)) 
        f.settimeout(0.5)
        f.send('Done')
        data = f.recv(1024)
        if data == 'Thanks':
            f.shutdown(socket.SHUT_RDWR)
            f.close()
            break
    except:
        f.close()
        time.sleep(2+random.random()*5)

我使用过Wireshark，发现数据包正在飞来飞去。 然而，“FinishedCount”似乎永远不会增加......有什么明显的错误，我在设置它时错过了吗？ 这是我第一次接触插座....

谢谢大家的帮助！

编辑：我对代码进行了以下更改：

在服务器上：socket.listen现在是socket.listen（5）

Answer 1

好吧，这花了我一段时间，但我想我弄清楚是什么导致了这个：

1. glglgl的答案是正确的 - 使用'localhost'会导致机器只听自己而不是网络上的其他机器。 这是罪魁祸首。
2. 将que中允许的数量从0增加到5可以降低在客户端获得“连接被拒绝”错误的可能性。

3. 我错误地认为无限时循环中的套接字连接可以无限快地关闭 - 但是，在两侧都有无限的while循环有时会导致客户端有时被计数两次，因为while循环不同步。 当然，这导致“客户端无关”的finishedCount增加了两倍，这导致服务器相信所有客户端都没有完成。 使用chown的代码（谢谢你chown！），这可以像这样处理：

    def main(): sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM) sock.bind((HOST, PORT)) sock.listen(0) FINISHEDCLIENTS = [] while 1: data = 'None' IP = [0, 0] try: client, ip = sock.accept() data = client.recv(1024) print "%s: Server recieved: '%s'" % (time.ctime(), data) if data == 'Done': print "%s: Server sending: 'Thanks'" % time.ctime() client.send('Thanks') if ip[0] in CLIENT_IPS and ip[0] not in FINISHEDCLIENTS: FINISHEDCLIENTS.append(ip[0]) if len(FINISHEDCLIENTS) == 12: #raise MyException break except Exception, e: print "%s: Server Exception - %s" % (time.ctime(), e) 

   在客户端，我将代码更改为此（当然，RandomPort与上面的服务器脚本中使用的相同）：

    SentFlag = 0 data = 'no' while SentFlag == 0: try: f = socket.socket(socket.AF_INET, socket.SOCK_STREAM) f.connect((IPofServer, RandomPort)) f.settimeout(20) f.send('Done') data = f.recv(1024) if data == 'Thanks': f.shutdown(socket.SHUT_RDWR) f.close() SentFlag = 1 except: f.close() time.sleep(2*random.random()) 

PS：我对.shutdown（）vs .close（）的理解是关闭连接，但如果它正在进行另一次通信，则不一定是套接字。 无论它正在做什么，.shutdown（）都会关闭套接字。 我虽然没有任何证据。

我认为应该这样做 - 再次感谢大家帮助修复此代码！

Answer 2

您的服务器有两个错误：

首先，这将打破内部for循环，而不是while循环：

if FinishedCount == 12:
    break

你的while循环没有终止条件。

第二，这种模式：

try:
    ...
except:
    pass

永远不应该使用。 你正在吞噬每一个例外并忽略它。 这是不好的做法，并会导致错误。 它应该是：

try:
    ...
except OneExceptionIWantToIgnore:
    pass
except:
    raise

解决这两个问题并回复我们的结果。

Answer 3

我相信这里的问题是使用RandomPort 。 每个客户端和服务器需要在同一端口上发送/接收才能工作。 另外， for ClientIP in ClientIPList(): if ClientIP == IP[0] and data == 'Done':循环有点冗余且不必要。 它可以替换为if ip[0] in clientIpList:并置于if data == 'Done':在其上方。

一些其他的想法; 永远不要将变量命名为与导入的内容相同的名称（如socket = socket.socket(..) ），因为这样您将无法再使用导入的库。 除非客户端/服务器在同一系统上运行或在同一子网内运行，否则settimeout(0.5)是缩短的方式。

我将您的代码与python socket文档中的一些示例代码合并，并提出了一些可以轻松适应您需求的工作。 这是脚本; 运行服务器和12个客户端的输出粘贴在下面。

server.py：

#!/usr/bin/python
# server.py

import sys
import socket
import time

HOST = ''
PORT = 50008

CLIENT_IPS = ["10.10.1.11"]

## No longer necessary if the nested loop isn't needed
#class MyException(Exception):
#    pass

def main():
    sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    sock.bind((HOST, PORT))
    sock.listen(0)

    finishedCount = 0

    while 1:
        data = 'None'
        IP = [0, 0]
        try:
            client, ip = sock.accept()
            data = client.recv(1024)
            print "%s: Server recieved: '%s'" % (time.ctime(), data)

            if data == 'Done':
                print "%s: Server sending: 'Thanks'" % time.ctime()
                client.send('Thanks')

                if ip[0] in CLIENT_IPS:
                    finishedCount += 1
                    print "%s: Finished Count: '%d'" % (time.ctime(), finishedCount)

                    if finishedCount == 12:
                        #raise MyException
                        break

        except Exception, e:
            print "%s: Server Exception - %s" % (time.ctime(), e)

        #except MyException:
        #    print "%s: All clients accounted for.  Server ending, goodbye!" % time.ctime()
        #    break

    # close down the socket, ignore closing exceptions
    try:
        sock.close()
    except:
        pass
    print "%s: All clients accounted for.  Server ending, goodbye!" % time.ctime()

if __name__ == '__main__':
    sys.exit(main())

client.py：

#!/usr/bin/python
# client.py

import sys
import time
import socket
import random

HOST = '10.10.1.11'
PORT = 50008

def main(n):
    while 1:
        try:
            s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
            s.connect((HOST, PORT))

            s.send('Done')
            print "%s: Client %d: Sending - 'Done'.." % (time.ctime(), n)

            data = s.recv(1024)
            print "%s: Client %d: Recieved - '%s'" % (time.ctime(), n, data)

            if data == 'Thanks':
                break

        except Exception, e:
            print "%s: Client %d: Exception - '%s'" % (time.ctime(), n, e)
            time.sleep(2 + random.random() * 5)
        finally:
            try:
                s.shutdown(socket.SHUT_RDWR)
            except:
                pass
            finally:
                try:
                    s.close()
                except:
                    pass

    print "%s: Client %d: Finished, goodbye!" % (time.ctime(), n)


if __name__ == '__main__':
    if len(sys.argv) > 1 and sys.argv[1].isdigit():
        sys.exit(main(int(sys.argv[1])))

运行12个客户端的输出：

[ 10:52 jon@hozbox.com ~/SO/python ]$ for x in {1..12}; do ./client.py $x && sleep 2; done
Fri Nov 18 10:52:44 2011: Client 1: Sending - 'Done'..
Fri Nov 18 10:52:44 2011: Client 1: Recieved - 'Thanks'
Fri Nov 18 10:52:44 2011: Client 1: Finished, goodbye!
Fri Nov 18 10:52:46 2011: Client 2: Sending - 'Done'..
Fri Nov 18 10:52:46 2011: Client 2: Recieved - 'Thanks'
Fri Nov 18 10:52:46 2011: Client 2: Finished, goodbye!
Fri Nov 18 10:52:48 2011: Client 3: Sending - 'Done'..
Fri Nov 18 10:52:48 2011: Client 3: Recieved - 'Thanks'
Fri Nov 18 10:52:48 2011: Client 3: Finished, goodbye!
Fri Nov 18 10:52:50 2011: Client 4: Sending - 'Done'..
Fri Nov 18 10:52:50 2011: Client 4: Recieved - 'Thanks'
Fri Nov 18 10:52:50 2011: Client 4: Finished, goodbye!
Fri Nov 18 10:52:52 2011: Client 5: Sending - 'Done'..
Fri Nov 18 10:52:52 2011: Client 5: Recieved - 'Thanks'
Fri Nov 18 10:52:52 2011: Client 5: Finished, goodbye!
Fri Nov 18 10:52:54 2011: Client 6: Sending - 'Done'..
Fri Nov 18 10:52:54 2011: Client 6: Recieved - 'Thanks'
Fri Nov 18 10:52:54 2011: Client 6: Finished, goodbye!
Fri Nov 18 10:52:56 2011: Client 7: Sending - 'Done'..
Fri Nov 18 10:52:56 2011: Client 7: Recieved - 'Thanks'
Fri Nov 18 10:52:56 2011: Client 7: Finished, goodbye!
Fri Nov 18 10:52:58 2011: Client 8: Sending - 'Done'..
Fri Nov 18 10:52:58 2011: Client 8: Recieved - 'Thanks'
Fri Nov 18 10:52:58 2011: Client 8: Finished, goodbye!
Fri Nov 18 10:53:01 2011: Client 9: Sending - 'Done'..
Fri Nov 18 10:53:01 2011: Client 9: Recieved - 'Thanks'
Fri Nov 18 10:53:01 2011: Client 9: Finished, goodbye!
Fri Nov 18 10:53:03 2011: Client 10: Sending - 'Done'..
Fri Nov 18 10:53:03 2011: Client 10: Recieved - 'Thanks'
Fri Nov 18 10:53:03 2011: Client 10: Finished, goodbye!
Fri Nov 18 10:53:05 2011: Client 11: Sending - 'Done'..
Fri Nov 18 10:53:05 2011: Client 11: Recieved - 'Thanks'
Fri Nov 18 10:53:05 2011: Client 11: Finished, goodbye!
Fri Nov 18 10:53:07 2011: Client 12: Sending - 'Done'..
Fri Nov 18 10:53:07 2011: Client 12: Recieved - 'Thanks'
Fri Nov 18 10:53:07 2011: Client 12: Finished, goodbye!
[ 10:53 jon@hozbox.com ~/SO/python ]$

服务器同时运行的输出：

[ 10:52 jon@hozbox.com ~/SO/python ]$ ./server.py
Fri Nov 18 10:52:44 2011: Server recieved: 'Done'
Fri Nov 18 10:52:44 2011: Server sending: 'Thanks'
Fri Nov 18 10:52:44 2011: Finished Count: '1'
Fri Nov 18 10:52:46 2011: Server recieved: 'Done'
Fri Nov 18 10:52:46 2011: Server sending: 'Thanks'
Fri Nov 18 10:52:46 2011: Finished Count: '2'
Fri Nov 18 10:52:48 2011: Server recieved: 'Done'
Fri Nov 18 10:52:48 2011: Server sending: 'Thanks'
Fri Nov 18 10:52:48 2011: Finished Count: '3'
Fri Nov 18 10:52:50 2011: Server recieved: 'Done'
Fri Nov 18 10:52:50 2011: Server sending: 'Thanks'
Fri Nov 18 10:52:50 2011: Finished Count: '4'
Fri Nov 18 10:52:52 2011: Server recieved: 'Done'
Fri Nov 18 10:52:52 2011: Server sending: 'Thanks'
Fri Nov 18 10:52:52 2011: Finished Count: '5'
Fri Nov 18 10:52:54 2011: Server recieved: 'Done'
Fri Nov 18 10:52:54 2011: Server sending: 'Thanks'
Fri Nov 18 10:52:54 2011: Finished Count: '6'
Fri Nov 18 10:52:56 2011: Server recieved: 'Done'
Fri Nov 18 10:52:56 2011: Server sending: 'Thanks'
Fri Nov 18 10:52:56 2011: Finished Count: '7'
Fri Nov 18 10:52:58 2011: Server recieved: 'Done'
Fri Nov 18 10:52:58 2011: Server sending: 'Thanks'
Fri Nov 18 10:52:58 2011: Finished Count: '8'
Fri Nov 18 10:53:01 2011: Server recieved: 'Done'
Fri Nov 18 10:53:01 2011: Server sending: 'Thanks'
Fri Nov 18 10:53:01 2011: Finished Count: '9'
Fri Nov 18 10:53:03 2011: Server recieved: 'Done'
Fri Nov 18 10:53:03 2011: Server sending: 'Thanks'
Fri Nov 18 10:53:03 2011: Finished Count: '10'
Fri Nov 18 10:53:05 2011: Server recieved: 'Done'
Fri Nov 18 10:53:05 2011: Server sending: 'Thanks'
Fri Nov 18 10:53:05 2011: Finished Count: '11'
Fri Nov 18 10:53:07 2011: Server recieved: 'Done'
Fri Nov 18 10:53:07 2011: Server sending: 'Thanks'
Fri Nov 18 10:53:07 2011: Finished Count: '12'
Fri Nov 18 10:53:07 2011: All clients accounted for.  Server ending, goodbye!
[ 10:53 jon@hozbox.com ~/SO/python ]$

Answer 4

调用listen（0）不会设置积压，因此您更有可能拒绝连接。 服务器端套接字也永远不会关闭。 暂时摆脱尝试/排除，这样你就可以看出真正的问题是什么。 否则处理显式的socket.error异常。

Answer 5

如果你这样做

socket.bind(('localhost', RandomPort))

您的服务器机器只接受来自它自己的连接，即localhost。

相反，做

socket.bind(('', RandomPort))

监听所有接口。