Tom Ordonez

Data Science, Analytics, Growing Teams

Python Socket Syntax


As seen on late night TV...

  • Python3
  • Linux

Thou shall:

import socket
sux = socket.socket(socket.AF_INET, socket.SOCK_STREAM)

Did I dream this? I could be sure that I wrote this tutorial before but I cannot find it.

To read the official docs about Python sockets go here.

First you start with importing the module:

import socket

Then you need to create a socket object and pass some arguments:

  • socket.AF_INET: This means address family internet protocol v4
  • socket.SOCK_STREAM: This means a TCP socket.

Other arguments

These are the default for IPv4 and TCP:

  • socket.AF_INET
  • socket.SOCK_STREAM

If you want IPv6:

  • socket.AF_INET6

If you want UDP:

  • socket.DGRAM

Different socket families use different number of arguments:

  • AF_INET: A pair-tuple (host, port).
  • AF_INET6: A four-tuple (host, port, flowinfo, scopeid).

You can also use bluetooth:

  • AF_BLUETOOTH

Closing the socket

If you do this:

import socket
sux = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
sux.connect( (host, port) )

Then you have to close it like this:

sux.close()

Keep in mind that the argument for IPv4 (AF_INET) is a pair-tuple:

sux.connect( (host, port) )

You don't need the whitespace but it helps me remember that it needs a tuple. This won't work:

sux.connect(host, port)

You can also open and close the socket like this:

with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as sux:
    sux.connect( (host, port) )

Which has a similar syntax as the open method.

with open('simpsons.txt', 'r') as fhandle:

Summary

The default:

  • AF_INET: IPv4
  • SOCK_STREAM: TCP

Using with...as:

import socket
with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as sux:
    sux.connect( (host, port) )
    ...
    something_awesome_here
    ...