app.py

from flask import Flask,render_template,request,redirect
from flask_sqlalchemy import SQLAlchemy
from datetime import datetime


app = Flask(__name__)
app.config['SQLALCHEMY_DATABASE_URI'] = "sqlite:///todo.db"
app.config['SQLALCHEMY_TRACK_MODIFICATIONS'] = False
db = SQLAlchemy(app)

class Todo(db.Model):
    sno = db.Column(db.Integer, primary_key = True) 
    title = db.Column(db.String(200), nullable=False) 
    desc = db.Column(db.String(500),nullable=False) 
    date_created = db.Column(db.DateTime, default=datetime.utcnow)

    def __repr__(self) -> str:
        return f"{self.sno} - {self.title}"

@app.route('/',methods=['POST','GET'])
def hello():
    if request.method == 'POST' :
        title = request.form['title']
        desc = request.form['desc']

        todo = Todo(title=title,desc=desc)
        db.session.add(todo)
        db.session.commit()
    allTodo  = Todo.query.all()
    return render_template('index.html',allTodo=allTodo)

@app.route('/update/<int:sno>',methods=['POST','GET'])
def update(sno):   
    if request.method == 'POST' :
        title = request.form['title']
        desc = request.form['desc']

        todo = Todo.query.filter_by(sno=sno).first()
        todo.title = title
        todo.desc = desc
        db.session.add(todo)
        db.session.commit() 
        redirect('/')
    todo = Todo.query.filter_by(sno=sno).first()
    return render_template('update.html',todo=todo)

@app.route('/delete/<int:sno>')
def delete(sno):
    todo =Todo.query.filter_by(sno=sno).first()
    db.session.delete(todo)
    db.session.commit()
    return redirect("/")


@app.route('/show')
def pro():
    allTodo =Todo.query.all()
    return 'products'

@app.route('/s')
def pr():
    return render_template('dark.html')

if __name__ == '__main__':
    app.run(debug=True)
    # app.run(debug=True, port=8000)