Setting Up the Initial App

In this guide, we’ll understand the process of setting up your FastAPI application. We’ll explore how to structure your project, create environment files, and manage dependencies using tools like poetry. By the end of this section, you’ll have a well-organized foundation for building your API.

Project Structure

A typical FastAPI project structure might look like this:

project_name/
├── app/
│   ├── __init__.py
│   ├── main.py
│   ├── models.py
│   └── routes.py
├── tests/
├── .gitignore
├── poetry.lock
├── pyproject.toml

• app directory: This is where your main application code will reside.
• main.py: The entry point for your application.
• models.py: Defines data models for your API.
• routes.py: Contains your path operations and routing logic.
• tests directory: For writing unit and integration tests.
• .gitignore: Specifies files and directories to exclude from Git version control.
• poetry.lock: Stores dependency versions for reproducibility.
• pyproject.toml: A configuration file for poetry.

Creating a Virtual Environment

To isolate your project’s dependencies from your system-wide Python environment, create a virtual environment using poetry:

Bash

poetry init

This will create a poetry.lock file and a pyproject.toml file.

Installing Dependencies

Add FastAPI and other required libraries to your pyproject.toml file:

Ini, TOML

[tool.poetry.dependencies]
python = "^3.7"
fastapi = "^0.95.0"
uvicorn = "^0.18.0"

Then, install them using poetry:

Bash

poetry install

Creating the Main Application File

Create a main.py file in your app directory and import the necessary modules:

Python

from fastapi import FastAPI

app = FastAPI()

Defining Path Operations

Start defining your API’s endpoints in the routes.py file:

Python

from fastapi import APIRouter

router = APIRouter()

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

Importing Routes in the Main File

Import the routes.py file in your main.py and include the router:

Python

from app import routes

app.include_router(routes.router)

Running the Application

To start your application, use uvicorn:

Bash

poetry run uvicorn app.main:app --reload

This will start the application on the default host and port.