Blueprint routes and templates in Flask - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to register a blueprint named 'blog' in a Flask app.

Flask

from flask import Flask, Blueprint

blog = Blueprint('blog', __name__)

app = Flask(__name__)
app.[1](blog)

Drag options to blanks, or click blank then click option'

Aregister_blueprint

Badd_blueprint

Cinclude_blueprint

Dattach_blueprint

Attempts:

3 left

💡 Hint

Common Mistakes

Using methods like add_blueprint or include_blueprint which do not exist.

In Flask, you register a blueprint to the app using register_blueprint.

2fill in blank

medium

Complete the route decorator to define a route '/post' inside the 'blog' blueprint.

Flask

from flask import Blueprint

blog = Blueprint('blog', __name__)

@blog.[1]('/post')
def show_post():
    return 'Post page'

Drag options to blanks, or click blank then click option'

Aregister

Burl_for

Cendpoint

Droute

Attempts:

3 left

💡 Hint

Common Mistakes

Using url_for or endpoint as decorators which are not route decorators.

The @blueprint.route() decorator defines a route inside a blueprint.

3fill in blank

hard

Fix the error in the blueprint template rendering code to render 'post.html'.

Flask

from flask import Blueprint, render_template

blog = Blueprint('blog', __name__, template_folder='templates')

@blog.route('/post')
def show_post():
    return [1]('post.html')

Drag options to blanks, or click blank then click option'

Arender_template

Brender

Crender_html

Dtemplate_render

Attempts:

3 left

💡 Hint

Common Mistakes

Using incorrect function names like render or render_html.

Use render_template to render HTML templates in Flask.

4fill in blank

hard

Fill both blanks to create a blueprint named 'shop' with a URL prefix '/store'.

Flask

from flask import Blueprint

shop = Blueprint('[1]', __name__, url_prefix='[2]')

Drag options to blanks, or click blank then click option'

Ashop

Bstore

C/shop

D/store

Attempts:

3 left

💡 Hint

Common Mistakes

Omitting the leading slash in the URL prefix or mixing names.

The blueprint name is 'shop' and the URL prefix should be '/store' with a leading slash.

5fill in blank

hard

Fill all three blanks to create a route '/item/' in the 'shop' blueprint that renders 'item.html' passing the id.

Flask

from flask import Blueprint, render_template

shop = Blueprint('shop', __name__)

@shop.[1]('/item/<int:id>')
def show_item([2]):
    return [3]('item.html', id=id)

Drag options to blanks, or click blank then click option'

Aroute

Bid

Crender_template

Durl_for

Attempts:

3 left

💡 Hint

Common Mistakes

Using url_for instead of render_template, or wrong parameter names.

The route decorator is route, the function parameter is id, and the template is rendered with render_template.

Practice

1. What is the main purpose of using a Blueprint in a Flask application?

easy

A. To handle user authentication automatically

B. To organize routes and templates into reusable components

C. To create a new Flask app instance

D. To connect Flask with a database

Solution

1. Step 1: Understand Blueprint role

   A Blueprint groups related routes and templates to keep code organized.

2. Step 2: Compare other options

   Connecting to databases, creating app instances, or handling authentication are separate tasks.

3. Final Answer:

   To organize routes and templates into reusable components -> Option B

4. Quick Check:

   Blueprint = organize routes/templates [OK]

Hint: Blueprints group routes/templates for better app structure [OK]

Common Mistakes:

• Thinking Blueprint creates the app instance
• Confusing Blueprint with database connection
• Assuming Blueprint handles authentication automatically

2. Which of the following is the correct way to register a Blueprint named blog with a Flask app app using the URL prefix /blog?

easy

A. app.register_blueprint(blog, url_prefix='/blog')

B. app.register_blueprint('/blog', blog)

C. app.register_blueprint(blog.prefix('/blog'))

D. app.register_blueprint(blog, prefix_url='/blog')

Solution

1. Step 1: Recall correct method signature

   The method is register_blueprint(blueprint, url_prefix='...').

2. Step 2: Check options for correct syntax

   Only app.register_blueprint(blog, url_prefix='/blog') uses the correct method and parameter names.

3. Final Answer:

   app.register_blueprint(blog, url_prefix='/blog') -> Option A

4. Quick Check:

   register_blueprint with url_prefix = app.register_blueprint(blog, url_prefix='/blog') [OK]

Hint: Use url_prefix parameter to set Blueprint URL base [OK]

Common Mistakes:

• Swapping parameter order
• Using wrong parameter name like prefix_url
• Calling prefix as a method on Blueprint

3. Given this Blueprint code:

from flask import Blueprint, render_template
blog = Blueprint('blog', __name__, template_folder='templates')

@blog.route('/post')
def show_post():
    return render_template('post.html')

And this main app code:

from flask import Flask
app = Flask(__name__)
app.register_blueprint(blog, url_prefix='/blog')

What URL should you visit to see the post.html template rendered?

medium

A. /blog

B. /post

C. /blog/post

D. /post/blog

Solution

1. Step 1: Understand route and url_prefix

   The Blueprint route is '/post', and the Blueprint is registered with prefix '/blog'.

2. Step 2: Combine prefix and route

   The full URL becomes '/blog/post' to access the route.

3. Final Answer:

   /blog/post -> Option C

4. Quick Check:

   url_prefix + route = /blog/post [OK]

Hint: Combine url_prefix and route for full URL [OK]

Common Mistakes:

• Ignoring url_prefix and using only route
• Swapping url_prefix and route order
• Assuming url_prefix is not added to route

4. What is wrong with this Blueprint registration code?

from flask import Flask
app = Flask(__name__)
app.register_blueprint(blog, prefix='/blog')

medium

A. You cannot register blueprints in Flask

B. Blueprint must be registered before app creation

C. Blueprint name must be 'app' to register

D. The parameter should be url_prefix, not prefix

Solution

1. Step 1: Check parameter name in register_blueprint

   The correct parameter to set URL prefix is url_prefix, not prefix.

2. Step 2: Validate other options

   Blueprints register after app creation; name can be anything; Flask supports blueprints.

3. Final Answer:

   The parameter should be url_prefix, not prefix -> Option D

4. Quick Check:

   Correct param is url_prefix [OK]

Hint: Use url_prefix, not prefix, when registering Blueprint [OK]

Common Mistakes:

• Using prefix instead of url_prefix
• Trying to register Blueprint before app exists
• Thinking Blueprint name must be 'app'

5. You have two Blueprints, admin and user, both with a route /dashboard. How can you register them in your Flask app to avoid URL conflicts and keep URLs clear?

hard

A. Register each Blueprint with a different url_prefix, like /admin and /user

B. Rename one Blueprint's route to /dashboard2

C. Register both Blueprints without any url_prefix

D. Use the same url_prefix for both Blueprints

Solution

1. Step 1: Understand URL conflicts

   Both Blueprints have the same route /dashboard, which causes conflicts if no prefix is used.

2. Step 2: Use url_prefix to separate routes

   Assigning different url_prefix values like /admin and /user keeps URLs unique and organized.

3. Final Answer:

   Register each Blueprint with a different url_prefix, like /admin and /user -> Option A

4. Quick Check:

   Different url_prefix avoids route conflicts [OK]

Hint: Use unique url_prefix for each Blueprint to avoid conflicts [OK]

Common Mistakes:

• Not using url_prefix and causing route clashes
• Renaming routes manually instead of using prefixes
• Using same url_prefix for multiple Blueprints