Block definitions and overriding in Flask - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define a block named 'content' in a base template.

Flask

{% block [1] %}Default content{% endblock %}

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

Afooter

Bheader

Ccontent

Dsidebar

Attempts:

3 left

💡 Hint

Common Mistakes

Using a block name that doesn't match the child template's block.

The block name must match the one you want to override. Here, 'content' is the block defined.

2fill in blank

medium

Complete the child template code to override the 'content' block.

Flask

{% extends 'base.html' %}
{% block [1] %}Overridden content{% endblock %}

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

Afooter

Bsidebar

Cheader

Dcontent

Attempts:

3 left

💡 Hint

Common Mistakes

Overriding a block with a different name than defined in the base template.

To override a block, use the exact block name defined in the base template, here 'content'.

3fill in blank

hard

Fix the error in the child template to properly override the 'title' block.

Flask

{% extends 'base.html' %}
{% block [1] %}My Page Title{% endblock %}

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

Atitle

Bcontent

Cheader

Dfooter

Attempts:

3 left

💡 Hint

Common Mistakes

Using a wrong block name like 'content' instead of 'title'.

The block to override for the page title is named 'title' in the base template.

4fill in blank

hard

Fill both blanks to define and override a block named 'sidebar' with default and new content.

Flask

Base template:
{% block [1] %}Default sidebar{% endblock %}

Child template:
{% extends 'base.html' %}
{% block [2] %}Custom sidebar content{% endblock %}

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

Asidebar

Bcontent

Cheader

Dfooter

Attempts:

3 left

💡 Hint

Common Mistakes

Using different block names in base and child templates.

The block name must be the same in both base and child templates to override correctly.

5fill in blank

hard

Fill all three blanks to create a base template with 'header' and 'footer' blocks and override only the 'footer' block in the child template.

Flask

Base template:
{% block [1] %}Site Header{% endblock %}
{% block [2] %}Site Footer{% endblock %}

Child template:
{% extends 'base.html' %}
{% block [3] %}Custom Footer{% endblock %}

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

Aheader

Bfooter

Ccontent

Dsidebar

Attempts:

3 left

💡 Hint

Common Mistakes

Overriding the wrong block or mismatching block names.

The base template defines 'header' and 'footer' blocks. The child overrides only the 'footer' block.

Practice

1. What is the main purpose of using {% block %} in Flask templates?

easy

A. To include external CSS files

B. To define sections that child templates can override

C. To write Python code inside templates

D. To create comments in the template

Solution

1. Step 1: Understand block usage in Flask templates

   The {% block %} tag defines a section in a base template that child templates can replace or extend.

2. Step 2: Identify the purpose of blocks

   Blocks allow flexible template inheritance by letting child templates override specific parts without rewriting the whole template.

3. Final Answer:

   To define sections that child templates can override -> Option B

4. Quick Check:

   Blocks = override sections [OK]

Hint: Blocks mark replaceable sections in templates [OK]

Common Mistakes:

• Confusing blocks with comments
• Thinking blocks run Python code
• Using blocks to include CSS

2. Which of the following is the correct syntax to override a block named content in a child template?

easy

A. {% block content %}New content{% endblock %}

B. {% extends content %}New content{% endextends %}

C. {% override content %}New content{% endoverride %}

D. {% include content %}New content{% endinclude %}

Solution

1. Step 1: Recall block override syntax

   To override a block, use {% block block_name %}...{% endblock %} in the child template.

2. Step 2: Check each option

   Only {% block content %}New content{% endblock %} uses the correct {% block %} and {% endblock %} tags with the block name.

3. Final Answer:

   {% block content %}New content{% endblock %} -> Option A

4. Quick Check:

   Override block = {% block %}...{% endblock %} [OK]

Hint: Override blocks with {% block name %}...{% endblock %} [OK]

Common Mistakes:

• Using {% extends %} instead of {% block %} to override
• Using non-existent tags like {% override %}
• Confusing {% include %} with block override

3. Given the base template base.html with:

{% raw %}{% block title %}Base Title{% endblock %}{% endraw %}

and child template child.html with:

{% raw %}{% extends 'base.html' %}{% block title %}Child Title{% endblock %}{% endraw %}

What will be displayed in the title block when rendering child.html?

medium

A. Base Title

B. Base TitleChild Title

C. Child Title

D. An error occurs

Solution

1. Step 1: Understand template inheritance

   The child template extends the base and overrides the title block.

2. Step 2: Determine which block content is used

   Since the child overrides the block, the content shown is from the child: "Child Title".

3. Final Answer:

   Child Title -> Option C

4. Quick Check:

   Child block overrides base block [OK]

Hint: Child block content replaces base block content [OK]

Common Mistakes:

• Assuming base block content shows instead
• Thinking both contents concatenate automatically
• Expecting a syntax error

4. Identify the error in this child template code:

{% raw %}{% extends 'base.html' %}{% block content %}Hello{% endblock content %}{% endraw %}

medium

A. Incorrect block closing tag; should be {% endblock %} not {% endblock content %}

B. Missing {% block %} tag

C. Incorrect extends syntax

D. No error; code is correct

Solution

1. Step 1: Check block closing syntax

   The correct way to close a block is with {% endblock %} without repeating the block name.

2. Step 2: Identify the error in the code

   The code uses {% endblock content %}, which is invalid and causes a syntax error.

3. Final Answer:

   Incorrect block closing tag; should be {% endblock %} not {% endblock content %} -> Option A

4. Quick Check:

   Block ends with {% endblock %} only [OK]

Hint: Close blocks with {% endblock %} only, no name [OK]

Common Mistakes:

• Adding block name in endblock tag
• Omitting {% block %} tag
• Wrong quotes in extends

5. You have a base template with two blocks:

{% raw %}{% block header %}Base Header{% endblock %}{% block footer %}Base Footer{% endblock %}{% endraw %}

You want a child template to override only the footer block but keep the base header. Which is the correct child template code?

hard

A. {% raw %}{% extends 'base.html' %}{% block header %}Base Header{% endblock %}{% block footer %}Child Footer{% endblock %}{% endraw %}

B. {% raw %}{% extends 'base.html' %}{% block header %}Child Header{% endblock %}{% endraw %}

C. {% raw %}{% block footer %}Child Footer{% endblock %}{% endraw %}

D. {% raw %}{% extends 'base.html' %}{% block footer %}Child Footer{% endblock %}{% endraw %}

Solution

1. Step 1: Understand block overriding behavior

   Only blocks defined in the child template override the base. Blocks not overridden use base content.

2. Step 2: Check which blocks are overridden

   {% raw %}{% extends 'base.html' %}{% block footer %}Child Footer{% endblock %}{% endraw %} overrides only footer, so header remains from base.

3. Final Answer:

   {% extends 'base.html' %}{% block footer %}Child Footer{% endblock %} -> Option D

4. Quick Check:

   Override only needed blocks in child [OK]

Hint: Override only blocks you want to change [OK]

Common Mistakes:

• Overriding blocks unnecessarily
• Forgetting {% extends %} in child
• Defining blocks without extends