Adam Hopkins - Python Web Development with Sanic: An in-depth guide for Python web developers to improve the speed and scalability of web applications

Copyright 2021 Packt Publishing

All rights reserved. No part of this book may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, without the prior written permission of the publisher, except in the case of brief quotations embedded in critical articles or reviews.

Every effort has been made in the preparation of this book to ensure the accuracy of the information presented. However, the information contained in this book is sold without warranty, either express or implied. Neither the author, nor Packt Publishing, and its dealers and distributors will be held liable for any damages caused or alleged to be caused directly or indirectly by this book.

Packt Publishing has endeavored to provide trademark information about all of the companies and products mentioned in this book by the appropriate use of capitals. However, Packt Publishing cannot guarantee the accuracy of this information.

Early Access Publication: Python Web Development with Sanic

Early Access Production Reference: B17504

Published by Packt Publishing Ltd.

Livery Place

35 Livery Street

Birmingham

B3 2PB, UK

ISBN: 978-1-80181-441-6

Copyright 2022 Packt Publishing

All rights reserved. No part of this book may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, without the prior written permission of the publisher, except in the case of brief quotations embedded in critical articles or reviews.

Welcome to Packt Early Access. Were giving you an exclusive preview of this book before it goes on sale. It can take many months to write a book, but our authors have cutting-edge information to share with you today. Early Access gives you an insight into the latest developments by making chapter drafts available. The chapters may be a little rough around the edges right now, but our authors will update them over time. Youll be notified when a new version is ready.

This title is in development, with more chapters still to be written, which means you have the opportunity to have your say about the content. We want to publish books that provide useful information to you and other customers, so well send questionnaires out to you regularly. All feedback is helpful, so please be open about your thoughts and opinions. Our editors will work their magic on the text of the book, so wed like your input on the technical elements and your experience as a reader. Well also provide frequent updates on how our authors have changed their chapters based on your feedback.

You can dip in and out ofthis bookorfollow alongfrom start to finish; Early Access is designed to be flexible.We hope you enjoy getting to know more about the process of writing a Packt book. Join the exploration of new topics by contributing your ideas and see them come to life in print.

1. Introduction to Sanic and async frameworks
2. Organizing a project
3. Routing and Intaking HTTP Requests
4. Ingesting HTTP Data
5. Handling and Responding Views
6. Operating outside the Request Handler
7. Dealing with Security Concerns
8. Running a Sanic Server
9. Best Practices to Improve your Web Applications
10. Implementing Common Use Cases with Sanic

There should be oneand preferably only oneobvious way to do it.

- Tim Peters, The Zen of Python

Too often, this maxim of Python is taken to mean that there must be only one way to do something. Any Python web developer can simply look at the number of web frameworks that exist and tell you that the choice is not so simple. There are dozens of web frameworks on PyPI, and within the ecosystem of any single framework, you will find even more options to solve a single problem. Go ahead and type authentication into the search bar at https://pypi.org. Looking at the number of results, that there is only [one] obvious way to do it does not seem so obvious. Maybe this sentence needs a change. Perhaps it could read, There should be one obvious way for you to do it. Why? Because adding in the context that we are talking about your specific application brings us to the next level.

This is Sanic, and this is the goal of this book.

What may be obvious for someone building a stock portfolio tracker will not be obvious to someone building a streaming media player. Therefore, to figure out what the obvious solution is, we must first understand the problem. And, to understand the problem, we must be hyper-aware of our specific use case.

When trying to find a solution to a problem, many other tools and frameworks respond by saying: here is how you should do it. Do you want to read data from your web request? Heres how to validate it. Do you need cross-site request forgery (CSRF) protection? Heres the snippet you need to add. This approach fails to make you a better developer and fails to find the optimal solution for your use case.

Why should I validate my data this way? Why do I need this snippet to protect myself? Because someone else made the decision for you. You cannot answer these questions. All you know is that the framework documentationor some blog on the Internettold you to do this, so you did it.

And this is why Sanicand indeed, the booktakes a different approach. By the end of this book, we want you to know how to spot peculiar use cases, and how to bend the tooling to meet your needs. You should be able to think through different types of implementations and select one that is most meaningful for your needs. This will be the obvious solution.

Sanic prides itself on being unopinionated. That is not to say that the maintainers of the project do not have strong opinions. I welcome you to engage me or anyone in the community in a discussion about proxy forwarding, deployment strategies, authentication schemes, etc. You will certainly find passionate opinions. By unopinionated, we mean to say that Sanics job is to take care of the plumbing so all you need to do is build the logic. The decision of how to tackle problems is not the domain of the framework.

You will find that Sanic developers are most keen to find solutions that are hyper-focused on solving the particular challenges that they face. Developers use Sanic because it is fast and simple. But, you will also find that using Sanic means the obvious solution to a problem is not based upon Sanic but upon your unique application requirements.

The other side of the story is that sometimes your use case is not in need of a hyper-focused solution. This is also fine. For this reason, you will find a number of plugins (many of which are supported by active members of the Sanic core-developer team) or off-the-shelf solutions. We wholly support your adoption of them and their patterns. Throughout this book, our examples will steer away from implementations that require plugins. However, where there are popular solutions including plugins, we will also point them out to you for reference.

Our goal in this book is to learn to identify your unique application requirements and match them with the tools at our disposal to: (1) make our applications better; and (2) make us better developers.