Route decorator (@app.route) in Flask - Mini Project: Build & Apply

Building a Simple Flask Webpage with @app.route

📖 Scenario: You are creating a small web application using Flask. You want to show a welcome message on the homepage.

🎯 Goal: Build a Flask app that shows 'Welcome to Flask!' when you visit the homepage URL.

📋 What You'll Learn

Create a Flask app instance named app

Use the @app.route decorator to define the homepage route '/'

Define a function called home that returns the string 'Welcome to Flask!'

Run the Flask app with debug mode enabled

💡 Why This Matters

🌍 Real World

Web developers use Flask and the @app.route decorator to create web pages and APIs that respond to different URLs.

💼 Career

Understanding routing in Flask is essential for backend web development jobs that build Python web applications.

1

Create the Flask app instance

Import Flask from the flask module and create a Flask app instance called app.

Flask

from flask import Flask

# Create the Flask app instance called app
# Your code here

Need a hint?

Use app = Flask(__name__) to create the app instance.

2

Add the route decorator for homepage

Use the @app.route decorator with the route '/' to define the homepage route.

Flask

from flask import Flask

app = Flask(__name__)

# Use @app.route('/') to define the homepage route
# Your code here

Need a hint?

Write @app.route('/') just before the function that handles the homepage.

3

Define the homepage function

Define a function called home that returns the string 'Welcome to Flask!'.

Flask

from flask import Flask

app = Flask(__name__)

@app.route('/')
# Define the function home that returns 'Welcome to Flask!'
# Your code here

Need a hint?

Define def home(): and return the welcome string inside it.

4

Run the Flask app

Add the code to run the Flask app with debug mode enabled by calling app.run(debug=True) inside the if __name__ == '__main__': block.

Flask

from flask import Flask

app = Flask(__name__)

@app.route('/')
def home():
    return 'Welcome to Flask!'

# Add the code to run the app with debug=True
# Your code here

Need a hint?

Use the standard Python entry point check and call app.run(debug=True) inside it.