Getting Started with Flask

Flask is a lightweight and flexible Python web framework that's perfect for building web applications of any size. In this tutorial, we'll explore the basics of Flask and build a simple web application.

What is Flask?

Flask is a micro web framework written in Python. It's called "micro" because it doesn't require particular tools or libraries, making it incredibly flexible and easy to get started with.

Key Features

Lightweight: Minimal dependencies and easy to understand
Flexible: No fixed project structure or conventions
Extensible: Large ecosystem of extensions
Built-in development server: Quick testing and debugging
RESTful request dispatching: Easy API development

Installing Flask

First, let's install Flask using pip:

pip install Flask

Creating Your First Flask App

Here's a minimal Flask application:

from flask import Flask

app = Flask(__name__)

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

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

Save this as app.py and run it:

python app.py

Visit http://localhost:5000 in your browser, and you'll see "Hello, World!"

Understanding Flask Routes

Routes in Flask are defined using the @app.route() decorator:

@app.route('/about')
def about():
    return 'About Page'

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

Working with Templates

Flask uses Jinja2 templating engine. Create a template file:

<!DOCTYPE html>
<html>
<head>
    <title>{{ title }}</title>
</head>
<body>
    <h1>Welcome, {{ name }}!</h1>
</body>
</html>

Render it in your route:

from flask import render_template

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

Conclusion

Flask is an excellent choice for web development in Python. Its simplicity and flexibility make it perfect for both beginners and experienced developers. In future posts, we'll explore more advanced topics like database integration, authentication, and deployment.

Happy coding!

Getting Started with Flask: Building Your First Web Application