适用于同一端口上的新客户端的Python更新TCP / IP套接字

Question

I am working with a program that acts as a server, in that it receives a TCP/IP connection rather than making the connection. When the program is started, I am able to open a TCP/IP port within the program and connect to it using:

import socket
s = socket.create_connection(("localhost",20100))
s.send("PAUSE\30")
s.recv(1024)

This will pause my program. I can continue to send commands in this fashion. However, if I close the program, re-open the program, re-open the port in the program, and then try the same command, I receive:

s.send("PAUSE\30")
s.recv(1024)

---------------------------------------------------------------------------
error                                     Traceback (most recent call last)
<ipython-input-7-40f527ce990f> in <module>()
      1 s.send("PAUSE\30")
----> 2 s.recv(1024)[1:-1]

error: [Errno 10053] An established connection was aborted by the software in your host machine

If I open a new port, say 20101, in the program and try to connect to it again, I receive:

s = socket.create_connection(("localhost",20101))

---------------------------------------------------------------------------
error                                     Traceback (most recent call last)
<ipython-input-8-857374ef86d3> in <module>()
----> 1 s = socket.create_connection(("localhost",20101))

C:\Program Files\Enthought\Canopy\App\appdata\canopy-1.5.5.3123.win-x86_64\lib\socket.pyc in create_connection(address, timeout, source_address)
    569 
    570     if err is not None:
--> 571         raise err
    572     else:
    573         raise error("getaddrinfo returns an empty list")

error: [Errno 10061] No connection could be made because the target machine actively refused it

I have only been able to successfully reconnect if I restart the program, re-open the port, and restart my Python kernel.

I would like to still communicate to the program after it is closed and re-opened without needing to restart my Python kernel. Is it possible to do so? If not, why? If so, how could I augment my code to achieve this?

Answer 1

The problem I see there is the lack of s.close(). You need to properly close the connection when you close or exit the program for the actual socket descriptor to be free. Are you calling that?