Flask is a lightweight WSGI web application framework written in Python. It is designed to make getting started quick and easy while allowing for scalability to complex applications. Flask is classified as a microframework because it does not require particular tools or libraries.

Flask was developed by Armin Ronacher as part of the Pocoo project, which is a collection of Python libraries.

Key features include:

• Simple and easy to use
• Lightweight and modular
• Built-in development server and debugger
• Integrated support for unit testing
• URL routing and request handling
• Jinja2 templating engine for rendering HTML

You can install Flask using pip, Python’s package manager. Run the following command:

pip install Flask

You can create a new Flask application by creating a Python file (e.g., app.py) and adding the following code:

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

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

python app.py

This will start the development server, typically accessible at http://127.0.0.1:5000/.

URL routing in Flask allows you to map URLs to specific functions (views) in your application using decorators like @app.route().

Flask uses Jinja2 as its template engine. You can render templates using the render_template() function:

You can handle forms in Flask using the request object to access form data submitted via POST requests:

Flask does not come with built-in database support but can be integrated with SQLAlchemy or other ORMs by installing additional packages.

Flask provides several security features including protection against cross-site scripting (XSS), cross-site request forgery (CSRF), and secure cookies for session management.

Flask provides testing capabilities through its built-in test client, allowing you to simulate requests to your application:

import unittest class MyTestCase(unittest.TestCase): def setUp(self): self.app = app.test_client() def test_hello(self): response = self.app.get(‘/’) self.assertEqual(response.data, b’Hello, World!’)

Flask applications can be deployed on various platforms such as Heroku, AWS, or DigitalOcean using WSGI servers like Gunicorn or uWSGI.

Yes! Flask supports many extensions that provide additional functionality such as authentication, database integration, form validation, and more.

Yes! The Flask community is active with numerous forums, mailing lists, and resources available for developers seeking help or sharing knowledge.

Resources include:

• Official documentation at flask.palletsprojects.com
• Online courses on platforms like Uptaught,  and Coursera
• Tutorials on websites like Real Python and W3Schools

Common issues include understanding routing, managing dependencies, configuring settings properly, and debugging errors.

Yes! You can create RESTful APIs using Flask by defining routes that respond to HTTP methods (GET, POST, PUT, DELETE) and returning JSON responses.

Middleware refers to functions that process requests globally before they reach views or after they leave views, allowing you to add functionality such as logging or authentication.

Signals allow certain senders to notify receivers when certain actions occur within your application, enabling decoupled components.