II. Getting Started with FastAPI

A. Installation and Setup

FastAPI is a modern, fast (high-performance), web framework for building APIs with Python 3.7+ based on standard Python type hints. Before diving into FastAPI, let’s go through the installation and setup process.

1. Requirements and Dependencies

To get started with FastAPI, make sure you have the following requirements and dependencies in place:

a. Python Version Compatibility

FastAPI requires Python version 3.7 or above. It is recommended to use the latest Python version for optimal performance and compatibility.

b. Required Packages and Libraries

FastAPI has a few dependencies that need to be installed. These dependencies include:

fastapi: The FastAPI framework itself.
uvicorn: A lightning-fast ASGI server, recommended for running FastAPI in production.
pydantic: A library for data validation and parsing that powers FastAPI’s request and response models.

You can install these packages using the installation methods mentioned below.

2. Installation Methods

There are different methods to install FastAPI based on your preferred workflow. Here are three common installation methods:

a. Using pip

The easiest way to install FastAPI and its dependencies is by using pip, the Python package installer. Open your terminal or command prompt and run the following command:

pip install fastapi uvicorn[standard] pydantic

b. Using Virtual Environments

If you prefer to work in a virtual environment, you can create one using venv or virtualenv and then activate it. Once inside the virtual environment, run the same pip command as mentioned above to install FastAPI and its dependencies.

c. Using Docker

If you are familiar with Docker, you can use it to set up FastAPI in a containerized environment. Start by creating a Dockerfile and specify the necessary dependencies. Then build the Docker image and run it to start using FastAPI.

FROM python:3.9
WORKDIR /app
COPY requirements.txt .
RUN pip install -r requirements.txt
COPY . .
CMD ["uvicorn", "main:app", "--host", "0.0.0.0", "--port", "8000"]

These installation methods will ensure that FastAPI and its dependencies are properly installed, allowing you to start building APIs with FastAPI.

In the next section, we will explore the basic structure of a FastAPI application.

II. Getting Started with FastAPI

B. Project Structure and Organization

When starting a FastAPI project, it is important to establish a well-organized and maintainable structure. This section will cover recommended practices for organizing your project’s directories, as well as code organization best practices.

1. Recommended Directory Structure

a. Separating frontend and backend code

To keep your project organized and maintain a clear separation between frontend and backend code, it is recommended to have separate directories for each. For example:

my_project/
├── backend/
│   ├── main.py
│   ├── api/
│   │   ├── endpoints/
│   │   └── routes/
│   └── models/
└── frontend/
    ├── index.html
    ├── styles.css
    └── scripts.js

b. Organizing endpoints and routes

Within the backend directory, it is common to have separate directories for endpoints and routes. This helps keep related code together and makes it easier to locate specific functionality. For example:

backend/
├── main.py
├── api/
│   ├── endpoints/
│   │   ├── users.py
│   │   └── items.py
│   └── routes/
│       ├── auth.py
│       └── products.py
└── models/
    ├── user.py
    └── item.py

c. Managing database models and migrations

For projects that involve a database, it is recommended to have a separate directory for managing database models and migrations. This helps keep the database-related code organized and makes it easier to handle database schema changes. For example:

backend/
├── main.py
├── api/
│   ├── endpoints/
│   │   ├── users.py
│   │   └── items.py
│   └── routes/
│       ├── auth.py
│       └── products.py
└── database/
    ├── models/
    │   ├── user.py
    │   └── item.py
    └── migrations/
        ├── 0001_initial.py
        └── 0002_add_column.py

2. Code Organization Best Practices

a. Using modules and packages

FastAPI projects can benefit from using modules and packages to organize code. Modules allow you to group related functionality together, while packages provide a way to further organize modules. For example:

backend/
├── main.py
└── api/
    ├── endpoints/
    │   ├── __init__.py
    │   └── users.py
    └── routes/
        ├── __init__.py
        └── auth.py

b. Separating concerns with classes and functions

To improve code readability and maintainability, it is recommended to separate concerns by using classes and functions. Classes can encapsulate related functionality and provide a clear interface, while functions can handle specific tasks within a module or class. For example:

class UserService:
    def create_user(self, user_data: dict) -> User:
        # Implementation

def get_user(user_id: int) -> User:
    # Implementation

c. Implementing reusable components and utilities

To promote code reuse and modularity, consider implementing reusable components and utilities within your FastAPI project. These can be separate modules or packages that provide common functionality that can be used across different parts of your project. For example:

backend/
├── main.py
└── utils/
    ├── authentication.py
    └── validation.py

By following these project structure and code organization best practices, you can ensure that your FastAPI project is well-structured, maintainable, and scalable.