DEV Community

Nditah
Nditah

Posted on

Develop a Simple Python FastAPI ToDo App in 1 minute

#fastapi #python #fullstack #beginners

FastApi-App

Completed App |
FastApi Official Website |

  1. Make a Directory for the Project and navigate into it

    mkdir fastapi-app && cd fastapi-app

  2. Create a Python Virtual Environment and Activate it

    python3 -m venv venv
    ls
    source venv/bin/activate

  3. Install Fastapi

    pip install fastapi

  4. Install an ASGI server

    pip install "uvicorn[standard]"

  5. Install package for the template

    pip install python-multipart jinja2

  6. Install package for database support

    pip install sqlalchemy

  7. The Open the Project with VSCode and create three files: app.py, database.py and models.py

Note:
Update Pip python3 -m pip install --upgrade pip

app.py 

from fastapi import FastAPI, Depends, Request, Form, status

from starlette.responses import RedirectResponse
from starlette.templating import Jinja2Templates

from sqlalchemy.orm import Session
from database import SessionLocal, engine
import models

models.Base.metadata.create_all(bind=engine)

templates = Jinja2Templates(directory="templates")

app = FastAPI()

# Dependency
def get_db():
    db = SessionLocal()
    try: 
        yield db
    finally:
        db.close()

@app.get("/")
async def home(req: Request, db: Session = Depends(get_db)):
    todos = db.query(models.Todo).all()
    return templates.TemplateResponse("base.html", { "request": req, "todo_list": todos })

@app.post("/add")
def add(req: Request, title: str = Form(...), db: Session = Depends(get_db)):
    new_todo = models.Todo(title=title)
    db.add(new_todo)
    db.commit()
    url = app.url_path_for("home")
    return RedirectResponse(url=url, status_code=status.HTTP_303_SEE_OTHER)

@app.get("/update/{todo_id}")
def add(req: Request, todo_id: int, db: Session = Depends(get_db)):
    todo = db.query(models.Todo).filter(models.Todo.id == todo_id).first()
    todo.complete = not todo.complete
    db.commit()
    url = app.url_path_for("home")
    return RedirectResponse(url=url, status_code=status.HTTP_303_SEE_OTHER)


@app.get("/delete/{todo_id}")
def add(req: Request, todo_id: int, db: Session = Depends(get_db)):
    todo = db.query(models.Todo).filter(models.Todo.id == todo_id).first()
    db.delete(todo)
    db.commit()
    url = app.url_path_for("home")
    return RedirectResponse(url=url, status_code=status.HTTP_303_SEE_OTHER)
Enter fullscreen mode Exit fullscreen mode

models.py 

from email.policy import default
from sqlalchemy import Boolean, Column, Integer, String
from database import Base

class Todo(Base):
    __tablename__ = "todos"

    id = Column(Integer, primary_key=True)
    title = Column(String(100))
    complete = Column(Boolean, default=False)
Enter fullscreen mode Exit fullscreen mode

database.py 

import imp
from sqlalchemy import create_engine
from sqlalchemy.orm import sessionmaker
from sqlalchemy.ext.declarative import declarative_base

DB_URL = "sqlite:///./db.sqlite"

engine = create_engine(DB_URL, connect_args = { "check_same_thread": False })

SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)

Base = declarative_base()
Enter fullscreen mode Exit fullscreen mode

templates/base.html 

<!DOCTYPE html>
<html lang="en">
    <head>
        <meta charset="UTF-8">
        <meta name="viewport" content="width=device-width, initial-scale=1.0">
        <title>Todo App - Fastapi</title>
        <link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/semantic-ui@2.4.2/dist/semantic.min.css">
        <script src="https://cdn.jsdelivr.net/npm/semantic-ui@2.4.2/dist/semantic.min.js"></script>
    </head>
    <body>
        <div style="margin-top: 50px;" class="ui container">
            <h1 class="ui center aligned header">Fastapi ToDo App</h1>

            <form class="ui form" action="/add" method="post">
                <div class="field">
                    <label>Todo Title</label>
                    <input type="text" name="title" placeholder="Enter ToDo task...">
                    <br>
                </div>
                <button class="ui blue button" type="submit">Add</button>
            </form>

            <hr>

            {% for todo in todo_list %} 
            <div class="ui segment">
                <p class="ui big header">{{ todo.id }} | {{ todo.title }}</p>

                {% if todo.complete == False %}
                <span class="ui gray label">Not Complete</span>
                {% else %}
                <span class="ui green label">Complete</span>
                {% endif %}

                <a class="ui blue button" href="/update/{{ todo.id }}">Update</a>
                <a class="ui red button" href="/delete/{{ todo.id }}">Delete</a>

            </div>
            {% endfor %}

        </div>


    </body>

</html>
Enter fullscreen mode Exit fullscreen mode

  1. To run the app, with uvicorn using the file_name:app_instance

    uvicorn app:app --reload

Preview the App at http://127.0.0.1:8000/ and the out-of-the-box API Documentation

  1. Commit and push your code to github.com and Deactivate the Virtual Env.

    $ deactivate
    $ conda deactivate

Top comments (2)

Collapse
 
lil_b_1c4ecb93d28aab19e02 profile image
Lil B • • Edited

Hi @nditah this was great! Your app is awesome and I am trying to learn fastapi and python, so this was a great tutorial. I do have a question for you.

Most of the requests return a 303 status:

@app.post("/add")
def add(req: Request, title: str = Form(...), db: Session = Depends(get_db)):
    new_todo = models.Todo(title=title)
    db.add(new_todo)
    db.commit()
    url = app.url_path_for("home")
    return RedirectResponse(url=url, status_code=status.HTTP_303_SEE_OTHER)

@app.get("/update/{todo_id}")
def add(req: Request, todo_id: int, db: Session = Depends(get_db)):
    todo = db.query(models.Todo).filter(models.Todo.id == todo_id).first()
    todo.complete = not todo.complete
    db.commit()
    url = app.url_path_for("home")
    return RedirectResponse(url=url, status_code=status.HTTP_303_SEE_OTHER)

@app.get("/delete/{todo_id}")
def add(req: Request, todo_id: int, db: Session = Depends(get_db)):
    todo = db.query(models.Todo).filter(models.Todo.id == todo_id).first()
    db.delete(todo)
    db.commit()
    url = app.url_path_for("home")
    return RedirectResponse(url=url, status_code=status.HTTP_303_SEE_OTHER)
Enter fullscreen mode Exit fullscreen mode

I understand that 303 is a redirect status code, but can you explain to me why it would be used in this case? Wouldn't it make more sense to use a status code 200? When I tried to update the status code to:

@app.post("/add")
def add(req: Request, title: str = Form(...), db: Session = Depends(get_db)):
    new_todo = models.Todo(title=title)
    db.add(new_todo)
    db.commit()
    url = app.url_path_for("home")
    return RedirectResponse(url=url, status_code=status.HTTP_200_OK)
Enter fullscreen mode Exit fullscreen mode

This doesn't work and when I add or update a todo it just takes me to a new empty page. Do you have any advice on how I would be able to get status 200 responses instead of 303? The 303 works perfect, but I am not sure I understand the reasoning behind it. Would you be able to explain that too?

Collapse
 
congomusah profile image
Congo Musah •

Having difficulties in trying to install jinja2.
Having an error like :COULD NOT FIND A VERSION THAT SATISFIES THE REQUIREMNET JINJA2. Any help ??

Read next

pranta profile image

Why Rewriting Everything in Rust Won’t Solve All Your Problems

PRANTA Dutta -

rym_michaut profile image

👋🏻Goodbye Power BI! 📊 In 2025 Build AI/ML Dashboards Entirely Within Python 🤖

Rym -

ankur0904 profile image

How to undo the most recent local commits in Git?

Ankur Singh -

connormanraz profile image

Automated Session Control with Bluetooth: An Insight into ble-lock-session

Connor Manraz -