Blueprint creation and registration in Flask - Mini Project: Build & Apply

Blueprint creation and registration

📖 Scenario: You are building a simple Flask web app that has two parts: a main page and a user section. To keep the code organized, you will use Flask Blueprints.

🎯 Goal: Create a Flask Blueprint for the user section and register it with the main Flask app. This will help you separate routes and keep your app clean.

📋 What You'll Learn

Create a Blueprint named user_bp with the import name __name__ and URL prefix /user

Define a route /profile inside the user_bp Blueprint that returns the text 'User Profile'

Create the main Flask app instance named app

Register the user_bp Blueprint with the main app app

💡 Why This Matters

🌍 Real World

Blueprints help organize large Flask apps by grouping related routes and code. This makes apps easier to maintain and scale.

💼 Career

Many companies use Flask Blueprints to build modular web apps. Knowing how to create and register Blueprints is a key skill for Flask developers.

1

Create the user Blueprint

Import Blueprint from flask and create a Blueprint called user_bp with the import name __name__ and URL prefix /user.

Flask

# Import Blueprint and create user_bp with __name__ and url_prefix='/user'
# Your code here

Need a hint?

Think of Blueprint as a mini app inside your main app. You give it a name, the current file's name, and a URL prefix.

2

Add a route to the user Blueprint

Inside the user_bp Blueprint, define a route for /profile that returns the string 'User Profile'.

Flask

from flask import Blueprint

user_bp = Blueprint('user_bp', __name__, url_prefix='/user')

# Define a route '/profile' in user_bp that returns 'User Profile'
# Your code here

Need a hint?

Use the @user_bp.route('/profile') decorator to add the route, then define a function that returns the text.

3

Create the main Flask app

Import Flask from flask and create the main app instance called app.

Flask

from flask import Blueprint

user_bp = Blueprint('user_bp', __name__, url_prefix='/user')

@user_bp.route('/profile')
def profile():
    return 'User Profile'

# Import Flask and create app instance named app
# Your code here

Need a hint?

The main app is created by calling Flask(__name__). Don't forget to import Flask.

4

Register the Blueprint with the app

Register the user_bp Blueprint with the main Flask app app using app.register_blueprint(user_bp).

Flask

from flask import Flask, Blueprint

user_bp = Blueprint('user_bp', __name__, url_prefix='/user')

@user_bp.route('/profile')
def profile():
    return 'User Profile'

app = Flask(__name__)

# Register user_bp with app
# Your code here

Need a hint?

Use app.register_blueprint(user_bp) to connect the Blueprint to your main app.