Introduction to Flask

Flask is a micro web framework for Python that is simple and easy to use, making it an excellent choice for beginners who want to build web applications. In this guide, we'll walk you through the basics of Flask and get you started with your first Flask application.

Installation

To get started with Flask, you'll first need to install it. You can install Flask using pip, the Python package manager:

Your First Flask Application

Let's create a simple "Hello, Flask!" web application. Create a file named app.py with the following code:

from flask import Flask
app = Flask(__name)
@app.route('/')
def hello():
    return "Hello, Flask!"
if __name__ == '__main__':
    app.run()
        

Save the file and run it with the following command:

Your Flask application should now be running, and you can access it in your browser at http://localhost:5000.

Routing and Views

Flask uses routes to define which URLs trigger which functions. In the example above, @app.route('/') decorates the hello() function, making it accessible at the root URL. You can define multiple routes and views for your application.

Templates and HTML

Flask allows you to render HTML templates in your views. You can use the Jinja2 template engine to insert dynamic data into your HTML. Here's an example of rendering an HTML template:

from flask import Flask, render_template
app = Flask(__name)
@app.route('/')
def hello():
    return render_template('index.html', name='Flask')
        

Make sure to create an index.html file in a templates folder with the necessary HTML structure and placeholders for dynamic content.

Conclusion

Flask is a fantastic framework for beginners to start building web applications with Python. We've only scratched the surface in this guide, but you're now on your way to becoming a Flask developer. Explore the Flask documentation to learn more about its features and capabilities.