Part-01: FastAPI Fundamentals - Building Powerful APIs with Ease

The FastAPI Fundamentals Series

Part-01: Introduction to FastAPI

Part-02: Getting User Input

Part-03: Mastering Responses

Introduction

Welcome to the world of FastAPI! If you're looking to supercharge your Python API development, you're in the right place. In this guide, we'll walk through the FastAPI fundamentals, showing you how to build powerful APIs with speed and simplicity.

Prerequisites

Before we dive in, make sure you have Python installed on your machine.

It's good practice to use a virtual environment for your projects. Here's how to set up and activate a virtual environment:

# Create and activate a virtual environment (optional but recommended)

$ python -m venv venv
$ source venv/bin/activate  

# On Windows, use `venv\Scripts\activate`

You can install FastAPI and an ASGI server (like uvicorn) using:

# Install FastAPI and uvicorn
$ pip install fastapi uvicorn

Step 1: Your First FastAPI App

Let's start with the basics. Create a file named main.py and add the following code:

from fastapi import FastAPI

app = FastAPI()

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

Step 2: Run Your FastAPI App

Open a terminal and run your FastAPI app using the following command:

$ uvicorn main:app --reload

Visit http://127.0.0.1:8000 in your browser, and you should see the {"Hello": "World"} response.

Step 3: Path Parameters and Query Parameters

FastAPI makes it easy to handle parameters. Update your main.py:

from fastapi import FastAPI

app = FastAPI()

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

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

Now, visit http://127.0.0.1:8000/items/42?query_param=test.

Step 4: Interactive Documentation

FastAPI generates interactive documentation automatically.

Go to http://127.0.0.1:8000/docs to explore and test your API interactively.

Conclusion

Congratulations! You've just scratched the surface of what FastAPI can do.

With its automatic OpenAPI and JSON Schema documentation, this powerful framework makes API development a breeze.

In your FastAPI journey, explore more advanced features like dependency injection, authentication, and database integration.

Happy coding!