Python 3.X Unix Socket Example

Question

I have been searching the last couple of hours on finding a simple Server / Client Unix Socket Example. I have found examples for Python 2.X, but I am failing at finding one that works for Python 3.X.

I keep getting TypeErrors.

The example that I have been working with is:

client.py

# -*- coding: utf-8 -*-
import socket
import os
# import os, os.path

print("Connecting...")
if os.path.exists("/tmp/python_unix_sockets_example"):
    client = socket.socket( socket.AF_UNIX, socket.SOCK_DGRAM )
    client.connect("/tmp/python_unix_sockets_example")
    print("Ready.")
    print("Ctrl-C to quit.")
    print("Sending 'DONE' shuts down the server and quits.")
    while True:
#        try:
            x = input( "> " )
            if "" != x:
            print("SEND:", x)
                client.send( x )
                if "DONE" == x:
                    print("Shutting down.")
                break
#        except KeyboardInterrupt, k:
#            print("Shutting down.")
    client.close()
else:
    print("Couldn't Connect!")
    print("Done")

With the client portion, I was not sure how to get a KeyboardInterupt to work in 3.X, so I killed the Try and Except portions. Any Advice?
Also, the syntax from the example I used had multiple modules being loaded from one import import os, os.path Is this the old way of only loading os.path from os module?

server.py

# -*- coding: utf-8 -*-

import socket
import os
# import os, os.path
# import time

if os.path.exists("/tmp/python_unix_sockets_example"):
    os.remove("/tmp/python_unix_sockets_example")

print("Opening socket...")
server = socket.socket(socket.AF_UNIX, socket.SOCK_DGRAM)
server.bind("/tmp/python_unix_sockets_example")

print("Listening...")
while True:
    datagram = server.recv(1024)

    if not datagram:
        break
    else:
        print("-" * 20)
        print(datagram)
        if "DONE" == datagram:
            break
print("-" * 20)
print("Shutting down...")
server.close()
os.remove("/tmp/python_unix_sockets_example")
print("Done")

When I run this I get TypeError: 'str' does not support the buffer interface.
Does Python 3.4 Unix Sockets only support binary?
What is the easiest way to make this work?

Thanks in advance!

With the help of John Hobbs from www.velvetcache.org, I was able to make the above work in Python 3.4. Thanks for the help John! https://gist.github.com/jmhobbs/11276249 — Timis, May 01 '14 at 16:23

score 2 · Answer 1 · answered Jul 03 '15 at 08:06

To answer the OP's questions explicitly:

The "TypeError: 'str' does not support the buffer interface" error was caused by attempting to send/receive string-encoded data over a bytes interface.
Unix sockets have no knowledge of encodings, they pass raw bytes, and Python 3+ no longer does any magic bytes<->encoded string conversions for you, so in this sense yes, (Python 3(.4)) Unix sockets only support "binary".
The easiest way to make it work was as @jmhobbs demonstrated in his above-linked gist: you must .encode() your strings to bytes when client.send()'ing them and .decode() the bytes back to strings when server.recv()'ing them.

score -5 · Answer 2 · answered Sep 10 '14 at 00:09

-5

One thing you may need to do is replace if os.path.exists("/tmp/python_unix_sockets_example"): with if os.path.exists("/tmp/python_unix_sockets_example") == True:

answered Sep 10 '14 at 00:09

Jameson

1
1

1

It's exactly the same – Grief Mar 31 '16 at 16:31
2

Actually it's worse, to rephrase the line explicitly it would be `if os.path.exists("/tmp/python_unix_sockets_example") is True:` whereas the `==` is for matching a variable to a value. As in `if x == "some text string": print(x)`. – Ben Jan 24 '18 at 06:32

Python 3.X Unix Socket Example

2 Answers2

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