FastAPI: A Course on API Integration with Modern Python

FastAPI is a modern web framework for building APIs with Python. It is designed to be fast, easy to use, and scalable. In this tutorial, we will cover how to integrate APIs using FastAPI.

First, we need to install FastAPI and its dependencies. We can do this using pip, the Python package installer. Open a terminal window and run the following command:

pip install fastapi uvicorn

Next, we need to create a new Python file for our FastAPI application. Let’s call it main.py. In this file, we will define our API routes and business logic.

from fastapi import FastAPI

app = FastAPI()

@app.get("/")
def read_root():
    return {"message": "Hello, World!"}

@app.get("/items/{item_id}")
def read_item(item_id: int, q: str = None):
    return {"item_id": item_id, "q": q}

In the code above, we import the FastAPI module and create a new FastAPI instance. We then define two API routes using decorators: one for the root URL ("/") and one for a specific item ID ("/items/{item_id}"). The read_root function returns a JSON response with a simple message, while the read_item function takes an item ID as a parameter and an optional query parameter q.

To run our FastAPI application, we need to start a web server. We can use Uvicorn, a fast ASGI server implementation. In the terminal window, run the following command:

uvicorn main:app --reload

This will start the Uvicorn server and run our FastAPI application. You should see output indicating that the server is running on http://localhost:8000. You can now open a web browser and navigate to this URL to access your API.

To test our API routes, you can use a tool like Postman or curl. For example, to test the root route, you can run the following command in the terminal:

curl http://localhost:8000/

This should return a JSON response with the message "Hello, World!". You can also test the item route by specifying an item ID and an optional query parameter:

curl http://localhost:8000/items/1?q=test

This should return a JSON response with the item ID and the query parameter.

In this tutorial, we have covered the basics of API integration using FastAPI. You can now extend your application by adding more routes, handling POST requests, implementing authentication, and integrating with databases or external APIs. FastAPI provides a rich set of features and tools to help you build powerful and scalable APIs with Python.