Route naming conventions in Flask - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define a route for the home page in Flask.

Flask

from flask import Flask
app = Flask(__name__)

@app.route('[1]')
def home():
    return "Welcome!"

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

A/home

B/index.html

C/

D/main

Attempts:

3 left

💡 Hint

Common Mistakes

Using '/home' instead of '/' for the home page route.

Adding file extensions like '.html' in the route.

The root URL / is the standard route for the home page in Flask.

2fill in blank

medium

Complete the code to define a route for a user profile page with a dynamic username.

Flask

@app.route('/user/[1]')
def profile(username):
    return f"User: {username}"

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

A<string:username>

B<username>

C<user>

D<name>

Attempts:

3 left

💡 Hint

Common Mistakes

Omitting the type like which works but is less explicit.

Using incorrect variable names like or that don't match the function parameter.

Flask uses <type:variable> syntax for dynamic route parts. <string:username> captures a string named 'username'.

3fill in blank

hard

Fix the error in the route decorator to correctly capture an integer post ID.

Flask

@app.route('/post/[1]')
def show_post(post_id):
    return f"Post {post_id}"

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

A<post_id>

B<id>

C<integer:post_id>

D<int:post_id>

Attempts:

3 left

💡 Hint

Common Mistakes

Using without type captures a string, not an integer.

Using which is not a valid Flask converter.

Flask requires <int:variable> to capture integers in routes. <integer:post_id> is invalid.

4fill in blank

hard

Fill both blanks to create a route for editing a post with an integer ID and a function named edit_post.

Flask

@app.route('/post/[1]/edit')
def [2](post_id):
    return f"Edit post {post_id}"

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

A<int:post_id>

Bedit_post

Cupdate_post

D<post_id>

Attempts:

3 left

💡 Hint

Common Mistakes

Using without type in the route.

Naming the function update_post instead of edit_post.

The route needs <int:post_id> to capture the post ID as an integer, and the function name should be edit_post to match the task.

5fill in blank

hard

Fill all three blanks to create a route for deleting a comment with integer IDs for post and comment, and a function named delete_comment.

Flask

@app.route('/post/[1]/comment/[2]/delete')
def [3](post_id, comment_id):
    return f"Delete comment {comment_id} from post {post_id}"

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

A<int:post_id>

B<int:comment_id>

Cdelete_comment

Dremove_comment

Attempts:

3 left

💡 Hint

Common Mistakes

Using string converters instead of int for IDs.

Naming the function remove_comment which is not the expected name.

Use <int:post_id> and <int:comment_id> to capture integer IDs, and name the function delete_comment to match the route's purpose.

Practice

1. Which of the following is the best practice for naming a Flask route for a user profile page?

easy

A. /user-profile

B. /UserProfile

C. /user_profile

D. /User-Profile

Solution

1. Step 1: Understand Flask route naming conventions

   Flask routes should be lowercase and use hyphens to separate words for readability and consistency.

2. Step 2: Evaluate each option

   /user-profile uses lowercase letters and hyphens, which is the recommended style. Options B and D use uppercase letters, which is not standard. /user_profile uses underscores, which is less preferred than hyphens in URLs.

3. Final Answer:

   /user-profile -> Option A

4. Quick Check:

   Lowercase + hyphens = /user-profile [OK]

Hint: Use lowercase and hyphens for route names [OK]

Common Mistakes:

• Using uppercase letters in route names
• Using underscores instead of hyphens
• Mixing uppercase and lowercase inconsistently

2. Which of the following Flask route definitions is syntactically correct for a dynamic user ID?

easy

A. @app.route('/user/')

B. @app.route('/user/{id}')

C. @app.route('/user/:id')

D. @app.route('/user/')

Solution

1. Step 1: Recall Flask dynamic route syntax

   Flask uses angle brackets with optional type converters like <int:id> to define dynamic parts.

2. Step 2: Check each option's syntax

   @app.route('/user/') correctly uses <int:id>. @app.route('/user/{id}') uses curly braces which is invalid in Flask. @app.route('/user/:id') uses colon syntax from other frameworks, not Flask. @app.route('/user/') reverses type and variable name, which is incorrect.

3. Final Answer:

   @app.route('/user/<int:id>') -> Option A

4. Quick Check:

   Flask dynamic route = <type:variable> [OK]

Hint: Use syntax for dynamic integer routes [OK]

Common Mistakes:

• Using curly braces instead of angle brackets
• Reversing type and variable name order
• Using colon syntax from other frameworks

3. What will be the output when accessing the route /product/42 given this Flask code?

@app.route('/product/')
def show_product(product_id):
    return f"Product ID: {product_id}"

medium

A. TypeError

B. Product ID: 42

C. 404 Not Found

D. Product ID: product_id

Solution

1. Step 1: Understand route matching and parameter passing

   The route /product/<int:product_id> captures the integer 42 and passes it as product_id to the function.

2. Step 2: Evaluate the function return

   The function returns a string with the product ID inserted, so it returns "Product ID: 42".

3. Final Answer:

   Product ID: 42 -> Option B

4. Quick Check:

   Dynamic route passes 42 correctly [OK]

Hint: Dynamic routes pass variables to functions as parameters [OK]

Common Mistakes:

• Expecting the variable name as string output
• Confusing 404 error with route syntax
• Assuming type errors without cause

4. Identify the error in this Flask route definition:

@app.route('/order/')
def order(order_id):
    return f"Order {order_id}"

Which fix is correct?

medium

A. Change order_id to orderid in route and function

B. Remove int: and use <order_id> only

C. No fix needed; the code is correct

D. Add a trailing slash to the route like /order/<int:order_id>/

Solution

1. Step 1: Check route and function parameter consistency

   The route uses <int:order_id> and the function parameter is order_id, which matches correctly.

2. Step 2: Verify Flask route syntax and behavior

   The syntax is valid, and Flask accepts routes with or without trailing slashes. No error exists here.

3. Final Answer:

   No fix needed; the code is correct -> Option C

4. Quick Check:

   Matching names and valid syntax = correct code [OK]

Hint: Matching route variables and function params means no fix needed [OK]

Common Mistakes:

• Changing variable names unnecessarily
• Removing type converters without reason
• Thinking trailing slash is mandatory

5. You want to create a Flask route for blog posts with a slug (text) identifier. Which route name follows best practices and correctly captures the slug as a string?

hard

A. @app.route('/blogPost/<slug>')

B. @app.route('/blog_post/')

C. @app.route('/blog-post/<slug>')

D. @app.route('/blog-post/')

Solution

1. Step 1: Identify route naming conventions

   Use lowercase letters and hyphens for route names, so /blog-post/ is preferred over underscores or camelCase.

2. Step 2: Check dynamic segment syntax

   Flask uses <string:slug> to specify a string variable. @app.route('/blog-post/') uses both correct route naming and dynamic segment syntax.

3. Final Answer:

   @app.route('/blog-post/<string:slug>') -> Option D

4. Quick Check:

   Lowercase + hyphen + <string:var> = best practice [OK]

Hint: Use lowercase hyphens and for text routes [OK]

Common Mistakes:

• Using underscores or camelCase in route names
• Omitting type in dynamic segments
• Mixing naming styles inconsistently