Book Image

Learning Python

By : Fabrizio Romano
Book Image

Learning Python

By: Fabrizio Romano

Overview of this book

Learning Python has a dynamic and varied nature. It reads easily and lays a good foundation for those who are interested in digging deeper. It has a practical and example-oriented approach through which both the introductory and the advanced topics are explained. Starting with the fundamentals of programming and Python, it ends by exploring very different topics, like GUIs, web apps and data science. The book takes you all the way to creating a fully fledged application. The book begins by exploring the essentials of programming, data structures and teaches you how to manipulate them. It then moves on to controlling the flow of a program and writing reusable and error proof code. You will then explore different programming paradigms that will allow you to find the best approach to any situation, and also learn how to perform performance optimization as well as effective debugging. Throughout, the book steers you through the various types of applications, and it concludes with a complete mini website built upon all the concepts that you learned.
Table of Contents (20 chapters)
Learning Python
Credits
About the Author
Acknowledgements
About the Reviewers
www.PacktPub.com
Preface
Index

How does the Web work?


In a nutshell, HTTP is an asymmetric request-response client-server protocol. An HTTP client sends a request message to an HTTP server. The server, in turn, returns a response message. In other words, HTTP is a pull protocol in which the client pulls information from the server (as opposed to a push protocol in which the server pushes information down to the client). Take a look at the following image:

HTTP is based on TCP/IP (Transmission Control Protocol/Internet Protocol), which provides the tools for a reliable communication exchange.

An important feature of the HTTP protocol is that it's stateless. This means that the current request has no knowledge about what happened in previous requests. This is a limitation, but you can browse a website with the illusion of being logged in. Under the covers though, what happens is that, on login, a token of user information is saved (most often on the client side, in special files called cookies) so that each request the...