01-flask

Flask Basics

Installation

pip install flask

Basic Example

from flask import Flask
 
app = Flask(__name__)
 
@app.route('/')
def home():
    return 'Hello, Flask!'
 
if __name__ == '__main__':
    app.run(debug=True)

Basic Routing

Flask allows you to define routes using the @app.route() decorator. Each route maps a URL to a Python function.

@app.route('/about')
def about():
    return 'This is the About page.'

You can also add variables to your routes:

@app.route('/user/<username>')
def show_user(username):
    return f'User: {username}'

To specify allowed HTTP methods:

@app.route('/submit', methods=['POST'])
def submit():
    return 'Form submitted!'

GET method is the default, so you can omit it if you only want to handle GET requests.
POST method is used for submitting data.

Running the Application

To run the Flask application, use the following command in your terminal:

python app.py

Make sure to replace app.py with the name of your Python file containing the Flask code.