What is Flask in Python and How to Build a Web App with It?

Flask is a lightweight web framework for Python that allows you to build web applications quickly and with a minimal amount of code. It’s known for its simplicity and flexibility.

Installing Flask

Install Flask using pip:

pip install Flask

Basic Application

Create a simple web app:

from flask import Flask
app = Flask(__name__)

@app.route('/')
def hello_world():
    return 'Hello, World!'

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

Running the App

Execute the script and navigate to http://localhost:5000/ in your browser.

Templates

Use HTML templates with Jinja2:

from flask import render_template

@app.route('/hello/<name>')
def hello(name):
    return render_template('hello.html', name=name)

Routing and Views

Define routes to handle different URLs and HTTP methods:

@app.route('/submit', methods=['POST'])
def submit():
    # Handle form submission
    pass

Conclusion

Flask is a powerful yet simple framework for building web applications in Python. Its minimalistic approach allows developers to choose the tools and libraries they need.