Question

这是我的服务器应用程序：

import socket, sys

sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
sock.bind(("127.0.0.1", 1060))
sock.listen(1)
print("Server is ready to receive.")
s, sockname = sock.accept()
while True:
    data = s.recv(100)
    # dead lock happens without following 'if'
    #if not data:
        #break
    print("The client from {} said: {}".format(s.getpeername(), 
    data.decode("utf-8")))
    sys.stdout.flush()

这是客户：

import socket

sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
sock.connect(("127.0.0.1", 1060))
print("client is ready")
message = '''Hello, server, my name is client!
         Here is oversize message: saasdasdas
         asdasdasdasssasdasdasdasdasdacsdvas
         sdavsdvavsdavxcvxczvdsavsavadsvasdv
         xcavdasvdsavewavwvdsvdsavasdvdsavad
         sdavsvxcvdavawevsdavsdavsavwevsdvsa
         dsvasdvadsvdasvsdavsadvasdvsdavsdvv
         sacascascwdqdadqwdqwdqwdsadwqdqwdqw
         '''
data = message.encode("utf-8")
sock.sendall(data)
print("I have sent a message of {} length, now I want to close the 
sock!".format(len(data)))
sock.close()

消息的长度（391bytes）比服务器套接字接收缓冲区（100字节）长。

如果我不添加：

if not data:
    break

当客户端向服务器发送数据时，服务器的输出为：

The client from ('127.0.0.1', 63758) said:
The client from ('127.0.0.1', 63758) said:
The client from ('127.0.0.1', 63758) said:
The client from ('127.0.0.1', 63758) said:
The client from ('127.0.0.1', 63758) said:
(...dead loop...)

这里的方法recv()是阻塞的，它可以从套接字缓冲区接收100个字节。

在我看来，服务器将收到4次，直到数据为止发送完毕后，当所有数据都已发出时，服务器应用将在data = s.recv(100)被阻止并等待下一个数据。

但事实并非如此。而且我也感到困惑的是，现在它似乎是非阻塞recv()，为什么不打印data.decode("utf-8")？

使用阻塞recv（）时python tcp socket死循环

0 个答案: