tutorial05.py

from flask import Flask
from flask import render_template
from flask import redirect
from flask import url_for
from flask import request
from flask import session
from datetime import timedelta


app = Flask(__name__)
app.secret_key = "hello@123"
app.permanent_session_lifetime = timedelta(seconds=20)


@app.route("/")
def home():
    return render_template("derived.html")


@app.route("/login", methods=["POST", "GET"])
def login():
    if request.method == "POST":
        session.permanent = True
        user = request.form['nm']
        session["user"] = user
        return redirect(url_for("user"))
    else:
        if "user" in session:
            return redirect(url_for("user"))

        return render_template("login.html")


@app.route("/user")
def user():
    if "user" in session:
        user = session["user"]
        return f"<h1>{user}</h1>"
    else:
        return redirect(url_for("login"))


@app.route("/logout")
def logout():
    session.pop("user", None)
    return redirect(url_for("login"))


if __name__ == "__main__":
    app.run(debug=True)