FastAPI Cookbook: Develop high-performance APIs and web applications with Python

FastAPI Cookbook

Copyright © 2024 Packt Publishing

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First published: August 2024

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To my dear nephew, Marco.

You bring endless joy to our lives. I wish you a future filled with love, growth, and happiness. May you always find success and fulfillment in everything you do.

– Giunio De Luca

Foreword

Having worked alongside Giunio for over a year, I can confidently say that his expertise and passion for Python development are evident in every line of code he produces. I affirm this with no shadow of a doubt, as I am a developer with over 30 years of experience across several countries and prominent industries, including Microsoft, NATO, and IBM.

We naturally became friends due to our mutual respect and shared interests, both professional and personal. Giunio stood out in our team at Coreso, one of the European Regional Coordination Centers for high-voltage electricity flows. He has an impressive academic background coupled with extensive international experience. What truly sets him apart, however, is his deep and thorough understanding of Python and FastAPI. Giunio’s code is not only functional but also exceptionally clean and clear—a hallmark of a skilled developer, or in other words, a subject matter expert.

Beyond his technical prowess, Giunio possesses a quality that I find equally important: an open mind. He readily embraces new challenges, tackling them with both enthusiasm and a solid foundation of knowledge, which he diligently builds and extends if he does not already possess it. I believe that he has brought these qualities to fruition in creating this book, pushing it beyond the scope of a typical cookbook. For instance, dealing with real-time communication and WebSockets is something rarely found in other cookbooks, and finding the right solution for your needs can consume a lot of valuable time searching online.

This book promises to be a valuable resource for anyone seeking to become proficient in the use of FastAPI. Despite the excellent work the creators do with the product documentation, navigating it can easily lead to hours of frustration. Whether you’re a seasoned Python developer or just starting your journey, Giunio’s clear explanations and practical examples will guide you every step of the way.

So, let Giunio be your expert guide to the power and efficiency of FastAPI!

Antonio Ferraro

MSc Computer Science, Business Owner

Contributors

About the author

Giunio De Luca is a software engineer with over 10 years of experience in fields such as physics, sports, and administration. He graduated in industrial engineering from the University of Basilicata and holds a PhD in numerical simulations from Paris-Saclay University. His work spans developing advanced algorithms, creating sports analytics applications, and improving administrative processes. As an independent consultant, he collaborates with research labs, government agencies, and start-ups across Europe. He also supports coding education in schools and universities through workshops, lectures, and mentorship programs, inspiring the next generation of software engineers with his expertise and dedication.

With heartfelt gratitude, I thank my family and my loved ones for their continuous encouragement. I am also thankful to all my employers who have believed in my expertise, and my current clients and colleagues who keep trusting my work and providing me with valuable opportunities for professional growth.

About the reviewer

Adarsh Divakaran is an experienced backend developer with expertise in architecting, building, and deploying APIs, primarily using Python. He is the co-founder of Digievo Labs, a global technology firm. He loves reading all sorts of Python content and runs a newsletter, Python in the Wild, showcasing Python concepts and examples from open source projects. Adarsh also speaks at global Python conferences, including PyCascades, EuroPython, and FlaskCon.

Table of Contents

Preface

1

First Steps with FastAPI

Technical requirements

Setting up your development environment

Getting ready

How to do it...

Creating a new FastAPI project

Getting ready

How to do it...

There’s more...

See also

Understanding FastAPI basics

How to do it…

See also

Defining your first API endpoint

Getting ready

How to do it...

How it works…

Working with path and query parameters

Getting ready

How to do it…

How it works…

See also

Defining and using request and response models

Getting ready

How to do it...

See also

Handling errors and exceptions

How to do it…

There’s more…

See also

2

Working with Data

Technical requirements

Setting up SQL databases

Getting ready

How to do it…

Establishing a database connection

See also

Understanding CRUD operations with SQLAlchemy

Getting ready

How to do it…

See also

Integrating MongoDB for NoSQL data storage

Getting ready

How to do it…

See also

Working with data validation and serialization

Getting ready

How to do it…

Serialization and deserialization concepts

Advanced validation techniques

See also

Working with file uploads and downloads

Getting ready

How to do it…

Implementing file uploads

Managing file downloads and storage

See also

Handling asynchronous data operations

Getting ready

How to do it…

There’s more…

See also

Securing sensitive data and best practices

Getting ready

How to do it…

There’s more…

3

Building RESTful APIs with FastAPI

Technical requirements

Creating CRUD operations

How to do it…

How it works...

Creating RESTful Endpoints

Getting ready…

How to do it…

Testing your RESTful API

Getting ready…

How to do it...

See also

Handling complex queries and filtering

Getting ready…

How to do it...

Versioning your API

Getting ready…

How to do it...

There’s more…

See also

Securing your API with OAuth2

Getting ready…

How to do it…

There’s more…

See also

Documenting your API with Swagger and Redoc

Getting ready…

How to do it...

See also

4

Authentication and Authorization

Technical requirements

Setting up user registration

Getting ready

How to do it…

How it works...

See also

Working with OAuth2 and JWT for authentication

Getting ready

How to do it...

How it works…

See also

Setting up RBAC

Getting ready

How to do it...

There’s more…

Using third-party authentication

Getting ready

How to do it...

How it works…

See also

Implementing MFA

Getting ready

How to do it...

See also

Handling API key authentication

Getting ready

How to do it...

There’s more…

Handling session cookies and logout functionality

Getting ready

How to do it...

There’s more…

See also

5

Testing and Debugging FastAPI Applications

Technical requirements

Setting up testing environments

Getting ready

How to do it...

See also

Writing and running unit tests

Getting ready

How to do it…

See also

Testing API Endpoints

Getting ready

How to do it…

See also

Running tests techniques

Getting ready

How to do it...

Check test coverage

See also

Handling logging messages

Getting ready

How to do it...

There’s more

See also

Debugging techniques

Getting ready

How to do it...

Debugging with PDB

Debugging with VS Code

Debugging with PyCharm

See also

Performance testing for high traffic applications

Getting ready

How to do it...

See also

6

Integrating FastAPI with SQL Databases

Technical requirements

Setting up SQLAlchemy

Getting ready

How to do it...

How it works…

See also

Implementing CRUD operations

Getting ready

How to do it…

How it works…

Working with migrations

Getting ready

How to do it…

How it works…

See also

Handling relationships in SQL databases

Getting ready

How to do it…

See also

Optimizing SQL queries for performance

Getting ready

How to do it…

There’s more…

Securing sensitive data in SQL databases

Getting ready

How to do it…

See also

Handling transactions and concurrency

Getting ready

How to do it…

There’s more…

See also

7

Integrating FastAPI with NoSQL Databases

Technical requirements

Setting up MongoDB with FastAPI

Getting ready

How to do it…

See also

CRUD operations in MongoDB

Getting ready

How to do it…

See also

Handling relationships in NoSQL databases

Getting ready

How to do it…

See also

Working with indexes in MongoDB

Getting ready

How to do it…

How it works…

There’s more…

See also

Exposing sensitive data from NoSQL databases

Getting ready

How to do it…

There’s more…

See also

Integrating FastAPI with Elasticsearch

Getting ready

How to do it…

See also

Using Redis for caching in FastAPI

Getting ready

How to do it…

There’s more…

See also

8

Advanced Features and Best Practices

Technical requirements

Implementing dependency injection

Getting ready

How to do it…

How it works…

There’s more…

See also

Creating custom middleware

Getting ready…

How to do it…

How it works…

See also

Internationalization and localization

Getting ready

How to do it…

See also

Optimizing application performance

Getting ready

How to do it…

There’s more...

See also

Implementing rate limiting

Getting ready

How to do it…

There's more...

See also

Implementing background tasks

Getting ready

How to do it…

How it works…

See also

9

Working with WebSocket

Technical requirements

Setting up WebSockets in FastAPI

Getting ready

How to do it…

How it works…

See also

Sending and receiving messages over WebSockets

Getting ready

How to do it…

See also

Handling WebSocket connections and disconnections

Getting ready

How to do it…

Handling WebSocket errors and exceptions

Getting ready

How to do it…

See also

Implementing chat functionality with WebSockets

Getting ready

How to do it…

How it works…

See also

Optimizing WebSocket performance

Getting ready

How to do it…

There’s more…

See also

Securing WebSocket connections with OAuth2

Getting ready

How to do it…

See also

10

Integrating FastAPI with other Python Libraries

Technical requirements

Integrating FastAPI with gRPC

Getting ready

How to do it…

There’s more…

See also

Connecting FastAPI with GraphQL

Getting ready

How to do it…

See also

Using ML models with Joblib

Getting ready

How to do it…

See also

Integrating FastAPI with Cohere

Getting ready

How to do it…

See also

Integrating FastAPI with LangChain

Getting ready

How to do it…

See also

11

Middleware and Webhooks

Technical requirements

Creating custom ASGI middleware

Getting ready

How to do it…

How it works…

There’s more…

See also

Developing middleware for request modification

Getting ready

How to do it…

See also

Developing middleware for response modification

Getting ready

How to do it…

See also

Handling CORS with middleware

Getting ready

How to do it…

See also

Restricting incoming requests from hosts

Getting ready

How to do it…

See also

Implementing webhooks

Getting ready

How to do it…

How it works…

There’s more…

See also

12

Deploying and Managing FastAPI Applications

Technical requirements

Running the server with the FastAPI CLI

Getting ready

How to do it…

There’s more…

See also

Enabling HTTPS on FastAPI applications

Getting ready

How to do it…

There’s more…

See also

Running FastAPI applications in Docker containers

Getting ready

How to do it…

See also

Running the server across multiple workers

Getting ready

How to do it…

There’s more…

See also

Deploying your FastAPI application on the cloud

Getting started

How to do it…

There’s more…

See also

Shipping FastAPI applications with Hatch

Getting ready

How to do it…

There’s more…

See also

Index

Other Books You May Enjoy

Preface

FastAPI Cookbook is a vital resource for Python developers who want to master the FastAPI framework to build APIs. Created by Sebastián Ramírez Montaño, FastAPI was first released in December 2018. It quickly gained popularity and became one of the most widely used Python frameworks for building APIs.

The book starts by introducing FastAPI, showing its advantages, and it will help you set up your development environment. It then moves on to data handling, showing database integration and create, read, update and delete (CRUD) operations, to help you manage data effectively within your APIs.

As the book progresses, it explores how to create RESTful APIs, covering advanced topics such as complex queries, versioning, and extensive documentation. Security is also important, and the book has a chapter on implementing authentication mechanisms such as OAuth2 and JWT tokens to secure FastAPI applications.

Testing is an essential part of development, and the book offers strategies to ensure the quality and reliability of FastAPI applications. Deployment strategies are discussed, highlighting best practices for production environments. For applications with high traffic, the book examines scaling techniques to improve performance.

Extending FastAPI’s functionality is possible through middleware, and the book also demonstrates how to boost FastAPI’s capabilities by integrating it with other Python tools and frameworks to accommodate machine learning models and expose LLM RAG applications.

Real-time communication is handled with a chapter on WebSockets, and advanced data handling techniques are provided to manage large datasets and file management.

The book ends with a focus on serving real-world traffic with FastAPI, stressing deployment strategies and packaging shipping. Each chapter is carefully designed to build your expertise, making the FastAPI Cookbook a valuable guide for professional-grade API development.

Who this book is for

The book is tailored for intermediate to advanced Python developers who have a foundational understanding of web development concepts. It’s particularly beneficial for those seeking to build efficient, scalable APIs with the modern FastAPI framework. The book is a valuable resource for developers looking to enhance their API development skills and apply practical solutions to real-world programming challenges. Whether you’re looking to secure APIs, manage data effectively, or optimize performance, this book provides the knowledge and hands-on examples to elevate your expertise in FastAPI.

What this book covers

Chapter 1

, First Steps with FastAPI, serves as an introduction to the framework, emphasizing its speed, ease of use, and comprehensive documentation. This chapter is the gateway for you to set up your development environment, create your first FastAPI project, and explore its fundamental concepts.

Chapter 2

, Working with Data, is dedicated to mastering the critical aspect of data handling in web applications. It covers the intricacies of integrating, managing, and optimizing data storage using both SQL and NoSQL databases.

Chapter 3

, Building RESTful APIs with FastAPI, dives into the essentials of constructing RESTful APIs, which are fundamental to web services, enabling applications to communicate and exchange data efficiently.

Chapter 4

, Authentication and Authorization, delves into the critical realms of securing your web applications against unauthorized access. It covers the basics of user registration and authentication, the integration of OAuth2 protocols with JWT for enhanced security, and the creation of essential components for an API.

Chapter 5

, Testing and Debugging FastAPI Applications, pivots toward a crucial aspect of software development that ensures the reliability, robustness, and quality of your applications – testing and debugging.

Chapter 6

, Integrating FastAPI with SQL Databases, embarks on a journey to harness the full potential of SQL databases within FastAPI applications. It is meticulously designed to guide you through leveraging SQLAlchemy, a powerful SQL toolkit and Object-Relational Mapper (ORM) for Python.

Chapter 7

, Integrating FastAPI with NoSQL Databases, explores the integration of FastAPI with NoSQL databases by guiding you through the process of setting up and using MongoDB, a popular NoSQL database, with FastAPI. It covers CRUD operations, working with indexes for performance optimization, and handling relationships in NoSQL databases. Additionally, the chapter discusses integrating FastAPI with Elasticsearch for powerful search capabilities and implementing caching using Redis.

Chapter 8

, Advanced Features and Best Practices, explores advanced techniques and best practices to optimize the functionality, performance, and scalability of FastAPI applications. It covers essential topics such as dependency injection, custom middleware, internationalization, performance optimization, rate limiting, and background task execution.

Chapter 9

, Working with WebSockets, is a comprehensive guide to implementing real-time communication features in FastAPI applications using WebSockets. It covers setting up WebSocket connections, sending and receiving messages, handling connections and disconnections, error handling, and implementing chat functionality.

Chapter 10

, Integrating FastAPI with other Python Libraries, deep dives into the potential of FastAPI when coupled with external libraries, enhancing its capabilities beyond its core features. It provides a recipe-based approach to integrating FastAPI with various technologies, such as Cohere and LangChain, to build LLM RAG applications.

Chapter 11

, Middleware and Webhooks, delves into the advanced and crucial aspects of middleware and Webhooks in FastAPI. Middleware allows you to process requests and responses globally, while Webhooks enable your FastAPI application to communicate with other services by sending real-time data updates.

Chapter 12

, Deploying and Managing FastAPI Applications, covers the knowledge and tools needed to deploy FastAPI applications seamlessly, leveraging various technologies and best practices. You will learn how to utilize the FastAPI CLI to run your server efficiently, enable HTTPS to secure your applications, and containerize your FastAPI projects with Docker.

To get the most out of this book

You should have a fundamental understanding of Python programming, as the book assumes familiarity with Python syntax and concepts. Additionally, knowledge of web development principles, including HTTP, RESTful APIs, and JSON, will be beneficial. Familiarity with SQL and NoSQL databases, as well as experience with version control systems such as Git, will help you to fully grasp the content.

If you are using the digital version of this book, we advise you to type the code yourself or access the code via the GitHub repository (link available in the next section). Doing so will help you avoid any potential errors related to the copying and pasting of code.

Download the example code files

You can download the example code files for this book from GitHub at https://github.com/PacktPublishing/FastAPI-Cookbook

. If there’s an update to the code, it will be updated on the existing GitHub repository.

We also have other code bundles from our rich catalog of books and videos available at https://github.com/PacktPublishing/

. Check them out!

Conventions used

There are a number of text conventions used throughout this book.

Code in text: Indicates code words in text, database table names, folder names, filenames, file extensions, pathnames, dummy URLs, user input, and Twitter handles. Here is an example: Also, you will find only the messages from our logger_client in a newly created app.log file automatically created by the application.

A block of code is set as follows:

from locust import HttpUser, task

class ProtoappUser(HttpUser):

    host = http://localhost:8000

    @task

    def hello_world(self):

        self.client.get(/home)

When we wish to draw your attention to a particular part of a code block, the relevant lines or items are set in bold:

from pydantic import BaseModel

, Field

class Book(BaseModel):

    title: str

= Field(..., min_length=1, max_length=100)

    author: str

= Field(..., min_length=1, max_length=50)

    year: int

= Field(..., gt=1900, lt=2100)

Any command-line input or output is written as follows:

$ pytest --cov protoapp tests

Throughout this book, we will generally use Unix-like terminal commands. This might lead to compatibility issues with Windows for commands that run on multiple lines. If you are using a Windows terminal, consider adapting the newline character \ as follows:

$ python -m grpc_tools.protoc \

--proto_path=. ./grpcserver.proto \

--python_out=. \

--grpc_python_out=.

Here is the same line in CMD:

$ python -m grpc_tools.protoc ^

--proto_path=. ./grpcserver.proto ^

--python_out=. ^

--grpc_python_out=.

Here is the line in Powershell:

$ python -m grpc_tools.protoc `

--proto_path=. ./grpcserver.proto `

--python_out=. `

--grpc_python_out=.

Bold: Indicates a new term, an important word, or words that you see onscreen. For example, words in menus or dialog boxes appear in the text like this. Here is an example: This limit can be adjusted in the settings (Settings | Advanced Settings | Run/Debug | Temporary configurations limit).

Tips or important notes

Appear like this.

Sections

In this book, you will find several headings that appear frequently (Getting ready, How to do it..., How it works..., There’s more..., and See also).

To give clear instructions on how to complete a recipe, use these sections as follows.

Getting ready

This section tells you what to expect in the recipe and describes how to set up any software or preliminary settings required for it.

How to do it…

This section contains the steps required to follow the recipe.

How it works…

This section usually consists of a detailed explanation of what happened in the previous section.

There’s more…

This section consists of additional information about the recipe in order to make you more knowledgeable about the recipe.

See also

This section provides helpful links to other useful information for the recipe.

Get in touch

Feedback from our readers is always welcome.

General feedback: If you have questions about any aspect of this book, mention the book title in the subject of your message and email us at [email protected]

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Errata: Although we have taken every care to ensure the accuracy of our content, mistakes do happen. If you have found a mistake in this book, we would be grateful if you would report this to us. Please visit www.packtpub.com/support/errata

, select your book, click on the Errata Submission Form link, and enter the details.

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