app.py

import flask
import os
# from dotenv import load_dotenv
# load_dotenv()

app = flask.Flask(__name__, template_folder="./templates/")


@app.route('/')
def index():
    print('Route: /')
    return flask.render_template('index.html')

@app.route('/about')
def about():
    print('Route: /about')
    return flask.render_template('about.html')

@app.route('/user/<name>')
def user(name: str):
    print(f'Route: /user/{name}')
    return flask.render_template('user-name.html', name=name)

@app.route('/evaluate/<expression>')
def evaluate(expression: str):
    print(f'Route: /eval/{expression}')
    
    # You can do some processing here before rendering the template.
    result = eval(expression)
    print(f"\tResult: {result}")

    return flask.render_template('evaluate-expression.html', expression=expression, result=result)


if __name__ == '__main__':
    app.run(host='0.0.0.0',  port=int(os.environ.get('PORT', 7860)))