在 Python sockets 中尝试将数据从服务器发送到客户端时出现损坏的 pipe 错误

Question

I am trying to use "vanilla" Python sockets to transmit data from a server to a client, without using any asynchronous programming. My use case is the following: I would like a local Raspberry Pi to connect to my internet exposed server, and the server to send data through the created socket when a given event occurs.

I followed several tutorials on simple socket programming in Python to build the following code:

server.py

import socket
import time

def server():
    PORT = 65432
    s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
    s.bind(('0.0.0.0', PORT))
    s.listen(1)
    conn,address=s.accept()  # accept an incoming connection using accept() method which will block until a new client connects
    print("address: ", address[0])
    time.sleep(5)
    s.send("hey".encode())
    conn.close()
    return

server()

client.py

import socket
import time

HOST = "my.remote.domain"
PORT = 65432

with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
    s.connect((HOST, PORT))
    while True :
        print(s.recv(1024))
        time.sleep(1)

When launching the server and the client on their respective machine, I can see that the connexion is correctly made, since the IP address of the client is printed in the logs of the server. However, after few seconds and before sending any data, I get the following error on the server side:

address:  client_ip_address_appears_here
Traceback (most recent call last):
  File "main.py", line 32, in <module>
    receiver()
  File "main.py", line 18, in receiver
    s.send("heeey".encode())
BrokenPipeError: [Errno 32] Broken pipe

Meanwhile on the client side, no data is received:

b''
b''
b''
b''
b''
b''
b''
b''
b''

Is there a conceptual problem in the way I try to handle the socket?

Answer 1

After trying out the code, I think the biggest problem you have is that the server is trying to send on the wrong socket. ie this line:

s.send("hey".encode())

should be rewritten like this:

conn.send("hey".encode())

As it is, you are trying to send() on the TCP accepting-socket rather than on the TCP connection to the client, which doesn't make sense. On my (MacOS/X) system, the server process prints this error output:

Jeremys-Mac-mini-2:~ jaf$ python server.py
('address: ', '127.0.0.1')
Traceback (most recent call last):
File "server.py", line 18, in <module>
  server()
File "server.py", line 14, in server
  s.send("hey".encode())
socket.error: [Errno 57] Socket is not connected