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

Improving unique constraints in the models


When we coded the NotificationCategory model in the previous chapter, we specified the True value for the unique argument in the creation of the orm.Column instance named name. As a result, the migrations process generated the necessary unique constraint to make sure that the name field has unique values in the notification_category table. This way, the PostgreSQL database won't allow us to insert duplicate values for the notification_category.name column. However, the error message generated when we try to do so is not clear. The message includes details about the database structure that shouldn't be mentioned in the error message.

Run the following command to create a category with a duplicate name. There is already an existing category with the name equal to 'Warning'. The code file for the sample is included in the restful_python_2_03_01 folder, in the Flask01/cmd301.txt file:

http POST ":5000/service/notification_categories/" name='Warning'

The...