Book Image

Building Python Web APIs with FastAPI

By : Abdulazeez Abdulazeez Adeshina
Book Image

Building Python Web APIs with FastAPI

By: Abdulazeez Abdulazeez Adeshina

Overview of this book

RESTful web services are commonly used to create APIs for web-based applications owing to their light weight and high scalability. This book will show you how FastAPI, a high-performance web framework for building RESTful APIs in Python, allows you to build robust web APIs that are simple and intuitive and makes it easy to build quickly with very little boilerplate code. This book will help you set up a FastAPI application in no time and show you how to use FastAPI to build a REST API that receives and responds to user requests. You’ll go on to learn how to handle routing and authentication while working with databases in a FastAPI application. The book walks you through the four key areas: building and using routes for create, read, update, and delete (CRUD) operations; connecting the application to SQL and NoSQL databases; securing the application built; and deploying your application locally or to a cloud environment. By the end of this book, you’ll have developed a solid understanding of the FastAPI framework and be able to build and deploy robust REST APIs.
Table of Contents (14 chapters)
Part 1: An Introduction to FastAPI
Part 2: Building and Securing FastAPI Applications
Part 3: Testing And Deploying FastAPI Applications

Error handling

Earlier on in this chapter, we learned what status codes are and how they are useful in informing the client about the request status. Requests can return erroneous responses, and these responses can be ugly or have insufficient information about the cause of failure.

Errors from requests can result from attempting to access non-existent resources, protected pages without sufficient permissions, and even server errors. Errors in FastAPI are handled by raising an exception using FastAPI’s HTTPException class.

What Is an HTTP Exception?

An HTTP exception is an event that is used to indicate a fault or issue in the request flow.

The HTTPException class takes three arguments:

  • status_code: The status code to be returned for this disruption
  • detail: Accompanying message to be sent to the client
  • headers: An optional parameter for responses requiring headers

In our to-do route path definitions, we return a message when a to-do can’...