Book Image

Python Network Programming Cookbook - Second Edition

By : Pradeeban Kathiravelu, Gary Berger, Dr. M. O. Faruque Sarker
Book Image

Python Network Programming Cookbook - Second Edition

By: Pradeeban Kathiravelu, Gary Berger, Dr. M. O. Faruque Sarker

Overview of this book

Python Network Programming Cookbook - Second Edition highlights the major aspects of network programming in Python, starting from writing simple networking clients to developing and deploying complex Software-Defined Networking (SDN) and Network Functions Virtualization (NFV) systems. It creates the building blocks for many practical web and networking applications that rely on various networking protocols. It presents the power and beauty of Python to solve numerous real-world tasks in the area of network programming, network and system administration, network monitoring, and web-application development. In this edition, you will also be introduced to network modelling to build your own cloud network. You will learn about the concepts and fundamentals of SDN and then extend your network with Mininet. Next, you’ll find recipes on Authentication, Authorization, and Accounting (AAA) and open and proprietary SDN approaches and frameworks. You will also learn to configure the Linux Foundation networking ecosystem and deploy and automate your networks with Python in the cloud and the Internet scale. By the end of this book, you will be able to analyze your network security vulnerabilities using advanced network packet capture and analysis techniques.
Table of Contents (15 chapters)

Setting and getting the default socket timeout

Sometimes, you need to manipulate the default values of certain properties of a socket library, for example, the socket timeout.

How to do it...

You can make an instance of a socket object and call a gettimeout() method to get the default timeout value and the settimeout() method to set a specific timeout value. This is very useful in developing custom server applications.

We first create a socket object inside a test_socket_timeout() function. Then, we can use the getter/setter instance methods to manipulate timeout values.

Listing 1.6 shows socket_timeout as follows:

#!/usr/bin/env python 
# Python Network Programming Cookbook, Second Edition -- Chapter - 1 
# This program is optimized for Python 2.7.12 and Python 3.5.2. 
# It may run on any other version with/without modifications. 
 
 
import socket 
 
def test_socket_timeout(): 
    s = socket.socket(socket.AF_INET, socket.SOCK_STREAM) 
    print ("Default socket timeout: %s" %s.gettimeout()) 
    s.settimeout(100) 
    print ("Current socket timeout: %s" %s.gettimeout())     
     
if __name__ == '__main__': 
    test_socket_timeout() 
 
 

After running the preceding script, you can see how this modifies the default socket timeout as follows:

$ python 1_6_socket_timeout.py 
Default socket timeout: None
Current socket timeout: 100.0
  

How it works...

In this code snippet, we have first created a socket object by passing the socket family and socket type as the first and second arguments of the socket constructor. Then, you can get the socket timeout value by calling gettimeout() and alter the value by calling the settimeout() method. The timeout value passed to the settimeout() method can be in seconds (non-negative float) or None. This method is used for manipulating the blocking-socket operations. Setting a timeout of None disables timeouts on socket operations.