Python：用一些消息通过套接字发送文件

Question

我有一个使用python^{}的客户机-服务器脚本，其中客户机读取文件并通过套接字发送。它一直工作，直到我尝试在文件被传输后从服务器发送到客户端。i、 e.服务器接收到文件后发送一条消息“file Received” 服务器还使用^{}（以容纳并发客户端）

以下是服务器脚本：

#!/usr/bin/python
import socket
from threading import Thread
from SocketServer import ThreadingMixIn

HOST = '192.168.56.106'
TCP_PORT = 60001
BUFFER_SIZE = 1024


class ClientThread(Thread):

    def __init__(self, ip, port, sock):
        Thread.__init__(self)
        self.ip = ip
        self.port = port
        self.sock = sock

    def run(self):
        filename = 'mytext.txt'
        f = open(filename, 'wb')
        while True:
            data = self.sock.recv(1024)
            if not data:
                f.close()
                # self.sock.close()
                break
            f.write(data)
        self.sock.sendall("File received")
        self.sock.close()


tcpsock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
tcpsock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
tcpsock.bind((HOST, TCP_PORT))
threads = []

while True:
    tcpsock.listen(5)
    (conn, (ip, port)) = tcpsock.accept()
    newthread = ClientThread(ip, port, conn)
    newthread.start()
    threads.append(newthread)

for t in threads:
    t.join()

和客户端脚本：

^{pr2}$

它们显然都被困在^{}等待另一端发送数据。在

# strace -f -e network ./server.py
socket(PF_INET, SOCK_STREAM, IPPROTO_IP) = 3
setsockopt(3, SOL_SOCKET, SO_REUSEADDR, [1], 4) = 0
bind(3, {sa_family=AF_INET, sin_port=htons(60001), sin_addr=inet_addr("192.168.56.106")}, 16) = 0
listen(3, 5)                            = 0
accept(3, {sa_family=AF_INET, sin_port=htons(49045), sin_addr=inet_addr("192.168.56.106")}, [16]) = 4
Process 4537 attached
[pid  4532] listen(3, 5)                = 0
[pid  4532] accept(3,  <unfinished ...>
[pid  4537] recvfrom(4, "This is test file\n", 1024, 0, NULL, NULL) = 18
[pid  4537] recvfrom(4,


# strace -e network ./client.py
socket(PF_INET, SOCK_STREAM, IPPROTO_IP) = 3
connect(3, {sa_family=AF_INET, sin_port=htons(60001), sin_addr=inet_addr("192.168.56.106")}, 16) = 0
sendto(3, "This is test file\n", 18, 0, NULL, 0) = 18
File transfer completed
recvfrom(3,

编辑： 正如Pynchia建议的那样，设置一个超时可以修复它，下面是一个工作片段。在

while True:
    tcpsock.listen(5)
    (conn, (ip, port)) = tcpsock.accept()
    conn.settimeout(2)
    newthread = ClientThread(ip, port, conn)
    newthread.start()
    threads.append(newthread)

。。。。在

 def run(self):
        filename = 'mytext.txt'
        f = open(filename, 'wb')
        while True:
            try:
                data = self.sock.recv(1024)
            except timeout:
                pass
            if not data:
                f.close()
                # self.sock.close()
                break
            f.write(data)
            self.sock.sendall("File received")
        self.sock.close()

很有魅力。当然，上面对超时异常的处理需要更多的调优（至少我知道现在应该在哪里查找）。在

# strace -f -e network ./server.py
socket(PF_INET, SOCK_STREAM, IPPROTO_IP) = 3
setsockopt(3, SOL_SOCKET, SO_REUSEADDR, [1], 4) = 0
bind(3, {sa_family=AF_INET, sin_port=htons(60001), sin_addr=inet_addr("192.168.56.106")}, 16) = 0
listen(3, 5)                            = 0
accept(3, {sa_family=AF_INET, sin_port=htons(49566), sin_addr=inet_addr("192.168.56.106")}, [16]) = 4
Process 13161 attached
[pid 13156] listen(3, 5)                = 0
[pid 13156] accept(3,  <unfinished ...>
[pid 13161] recvfrom(4, "Hello 124\nThis is test file\n</em"..., 1024, 0, NULL, NULL) = 37
[pid 13161] sendto(4, "File received", 13, 0, NULL, 0) = 13
[pid 13161] recvfrom(4, "", 1024, 0, NULL, NULL) = 0
[pid 13161] +++ exited with 0 +++

Answer 1

默认情况下，套接字被创建为阻塞（参见官方文档中的this note）。在

所以在服务器上

data = self.sock.recv(1024)

当客户端无限期地发送完块文件时。在

而且，由于客户机接着从服务器接收返回的内容，所以两者最终陷入死锁。在

在服务器代码中，一种解决方案是使用

socket.setblocking(flag)

或使用设置超时

socket.settimeout(value)

也请看这个SO Q&A