Pydantic model definition in FastAPI - Mini Project: Build & Apply

Pydantic Model Definition in FastAPI

📖 Scenario: You are building a simple FastAPI app to manage a list of books. Each book has a title, author, and number of pages.

🎯 Goal: Create a Pydantic model to define the structure of a book. This model will help FastAPI validate incoming data and generate API docs.

📋 What You'll Learn

Create a Pydantic model named Book

Include fields title (string), author (string), and pages (integer)

Set up a FastAPI app instance named app

Create a POST endpoint /books/ that accepts a Book model

💡 Why This Matters

🌍 Real World

APIs often need to validate incoming data to avoid errors and security issues. Pydantic models help define clear data rules.

💼 Career

FastAPI and Pydantic are popular tools for backend development. Knowing how to define models and endpoints is essential for building reliable web services.

1

Create the Pydantic model

Write a Pydantic model named Book with these fields: title as str, author as str, and pages as int. Import BaseModel from pydantic.

FastAPI

from pydantic import BaseModel

# Define the Book model here
# Your code here

Need a hint?

Remember to import BaseModel from pydantic and create a class that inherits from it.

2

Set up FastAPI app instance

Import FastAPI from fastapi and create an app instance named app.

FastAPI

from fastapi import FastAPI

# Create FastAPI app instance
# Your code here

Need a hint?

Use app = FastAPI() to create the app instance.

3

Create POST endpoint to receive Book data

Define a POST endpoint /books/ using @app.post("/books/"). Create a function create_book that takes a parameter book of type Book.

FastAPI

# Define POST endpoint to create a book
# Your code here

Need a hint?

Use @app.post("/books/") decorator and define an async function with a book parameter typed as Book.

4

Complete the FastAPI app

Ensure the full code includes the Book model, the app instance, and the POST endpoint /books/ that returns the received book data.

FastAPI

# Finalize the FastAPI app
# Your code here

Need a hint?

Check that all parts are included and correctly indented.