Getting Started with FastAPI

Introduction: Getting Started with Your Cooking App

Welcome to your first step in building the AI Cooking Helper! In this lesson, you will learn how to set up the foundation of your web application using a modern web framework that is fast, efficient, and easy to use. This tool is designed for building APIs and web applications quickly, making it a great choice for projects that need to scale and remain maintainable. By the end of this lesson, you will have a working project that is connected to a database and ready to serve static files and handle cross-origin requests. This setup is essential for storing recipes, user data, and more as you continue to develop your cooking app. Everything you learn here will be used in future lessons as you add more features and functionality.

Project Structure Basics

Before we dive in, let’s look at how your project will be organized. A typical project using this tool has a main file (like main.py) that starts the application, and folders (like app/) that hold different parts of the code, such as routes and database configuration. For example, your project might look like this: tree cooking_helper/ │ ├── main.py └── app/ ├── __init__.py ├── routes.py └── db/ └── session.py main.py is where your application starts. The app/ folder keeps your code organized by separating routes and database setup. The db/ folder inside app/ contains files related to database configuration. This structure helps keep your code clean and easy to manage as your project grows. FastAPI is chosen for this project because it offers several advantages: Async support: FastAPI is built on top of modern Python async features, allowing for high performance and efficient handling of many simultaneous requests. Automatic OpenAPI/docs generation: FastAPI automatically generates interactive API documentation (using Swagger UI and ReDoc) based on your code, making it easy to test and understand your API. Pydantic validation: FastAPI uses Pydantic for data validation and serialization, ensuring that incoming and outgoing data matches your defined models and reducing boilerplate code. However, there are some trade-offs compared to alternatives like Django or Flask: Smaller ecosystem: FastAPI’s ecosystem is newer and smaller than Django’s or Flask’s, so there may be fewer third-party plugins or community resources available. Learning curve with async: While async support is powerful, it can introduce a learning curve if you are new to asynchronous programming in Python. Some libraries may not be fully compatible with async code, requiring extra care when integrating them.

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Setting Up the Application

Before you start coding, you need to install the required dependencies. Open your terminal and run:

Shell

pip install fastapi uvicorn sqlalchemy

pip install fastapi uvicorn sqlalchemy

fastapi is the main web framework.
uvicorn is the ASGI (Asynchronous Server Gateway Interface) server used to run your app.
sqlalchemy is the ORM (Object-relational mapping) for database interactions.

Note: In the CodeSignal environment, these packages are already installed for you. You can skip the installation step.

Let’s start by creating a basic application. In your main.py file, you will need to import the main application class, set up the database, configure static file serving, and enable CORS (Cross-Origin Resource Sharing).

Here is how you can set up your application:

Python

from fastapi import FastAPI
from fastapi.staticfiles import StaticFiles
from fastapi.middleware.cors import CORSMiddleware
from app.routes import router
from app.db.session import engine, Base

def create_app() -> FastAPI:
    app = FastAPI()
    Base.metadata.create_all(bind=engine)
    
    app.mount("/static", StaticFiles(directory="static"), name="static")

    app.add_middleware(
        CORSMiddleware,
        allow_origins=["*"],
        allow_methods=["*"],
        allow_headers=["*"],
    )

    app.include_router(router, prefix="/api")
    return app

app = create_app()

from fastapi import FastAPI
from fastapi.staticfiles import StaticFiles
from fastapi.middleware.cors import CORSMiddleware
from app.routes import router
from app.db.session import engine, Base

def create_app() -> FastAPI:
    app = FastAPI()
    Base.metadata.create_all(bind=engine)
    
    app.mount("/static", StaticFiles(directory="static"), name="static")

    app.add_middleware(
        CORSMiddleware,
        allow_origins=["*"],
        allow_methods=["*"],
        allow_headers=["*"],
    )

    app.include_router(router, prefix="/api")
    return app

app = create_app()

Here’s what’s happening:

The application is created and configured.
The database tables are created if they do not exist.
Static files are served from the static directory.
CORS is enabled to allow requests from any origin.
The main router is included under the /api prefix.

Introduction: Getting Started with Your Cooking App

Project Structure Basics

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Setting Up the Application

Connecting the Database and Creating Tables

Organizing Routes with Routers

Running the App

Summary and What’s Next