Book Image

Hands-On RESTful Python Web Services - Second Edition

By : Gaston C. Hillar
1 (1)
Book Image

Hands-On RESTful Python Web Services - Second Edition

1 (1)
By: Gaston C. Hillar

Overview of this book

Python is the language of choice for millions of developers worldwide that builds great web services in RESTful architecture. This second edition of Hands-On RESTful Python Web Services will cover the best tools you can use to build engaging web services. This book shows you how to develop RESTful APIs using the most popular Python frameworks and all the necessary stacks with Python, combined with related libraries and tools. You’ll learn to incorporate all new features of Python 3.7, Flask 1.0.2, Django 2.1, Tornado 5.1, and also a new framework, Pyramid. As you advance through the chapters, you will get to grips with each of these frameworks to build various web services, and be shown use cases and best practices covering when to use a particular framework. You’ll then successfully develop RESTful APIs with all frameworks and understand how each framework processes HTTP requests and routes URLs. You’ll also discover best practices for validation, serialization, and deserialization. In the concluding chapters, you will take advantage of specific features available in certain frameworks such as integrated ORMs, built-in authorization and authentication, and work with asynchronous code. At the end of each framework, you will write tests for RESTful APIs and improve code coverage. By the end of the book, you will have gained a deep understanding of the stacks needed to build RESTful web services.
Table of Contents (19 chapters)
Title Page
Dedication
About Packt
Contributors
Preface
Index

Adding unique constraints to the models


Our API has some important issues that we need to solve quickly. Right now, we can create many ESRB ratings with the same description. We shouldn't be able to do so, and therefore, we will make the necessary changes to the EsrbRating model to add a unique constraint on the description field. We will also add a unique constraint on the name field for the Game and Player models. This way, we will learn the necessary steps to make changes to the constraints for many models and reflect the changes in the underlying database schema through migrations.

Make sure you quit the Django development server. Remember that you just need to press Ctrl+ C in the Terminal or Command Prompt window in which it is running.

Now we will make changes to introduce unique constraints to the description and name fields for the models that we use to represent and persist the ESRB ratings, games, and players. Open the models.py file in the games_service/games folder and replace...