Book Image

Learning Python Design Patterns - Second Edition - Second Edition

By : Chetan Giridhar, Gennadiy Zlobin
Book Image

Learning Python Design Patterns - Second Edition - Second Edition

By: Chetan Giridhar, Gennadiy Zlobin

Overview of this book

With the increasing focus on optimized software architecture and design it is important that software architects think about optimizations in object creation, code structure, and interaction between objects at the architecture or design level. This makes sure that the cost of software maintenance is low and code can be easily reused or is adaptable to change. The key to this is reusability and low maintenance in design patterns. Building on the success of the previous edition, Learning Python Design Patterns, Second Edition will help you implement real-world scenarios with Python’s latest release, Python v3.5. We start by introducing design patterns from the Python perspective. As you progress through the book, you will learn about Singleton patterns, Factory patterns, and Façade patterns in detail. After this, we’ll look at how to control object access with proxy patterns. It also covers observer patterns, command patterns, and compound patterns. By the end of the book, you will have enhanced your professional abilities in software architecture, design, and development.
Table of Contents (19 chapters)
Learning Python Design Patterns Second Edition
Credits
Foreword
About the Author
About the Reviewer
www.PacktPub.com
Preface
Index

Understanding the Proxy design pattern


Proxy, in general terms, is a system that intermediates between the seeker and provider. Seeker is the one that makes the request, and provider delivers the resources in response to the request. In the web world, we can relate this to a proxy server. The clients (users in the World Wide Web), when they make a request to the website, first connect to a proxy server asking for resources such as a web page. The proxy server internally evaluates this request, sends it to an appropriate server, and gets back the response, which is then delivered to the client. Thus, a proxy server encapsulates requests, enables privacy, and works well in distributed architectures.

In the context of design patterns, Proxy is a class that acts as an interface to real objects. Objects can be of several types such as network connections, large objects in memory and file, among others. In short, Proxy is a wrapper or agent object that wraps the real serving object. Proxy could...