Template inheritance with base template in Django - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is template inheritance in Django?

Template inheritance lets you create a base template with common layout and extend it in child templates to reuse code and keep pages consistent.

beginner

How do you specify a base template to extend in a Django template?

Use the {% raw %}{% extends 'base.html' %}{% endraw %} tag at the top of your child template to inherit from 'base.html'.

beginner

What is the purpose of {% raw %}{% block %}{% endblock %}{% endraw %} tags in Django templates?

Blocks define sections in the base template that child templates can override to insert their own content.

intermediate

If a child template does not override a block, what happens?

The content inside the block in the base template is used as default and shown in the rendered page.

beginner

Why is template inheritance useful in web development?

It saves time by avoiding repeated code, ensures consistent look across pages, and makes maintenance easier by changing the base template once.

Which tag do you use to inherit from a base template in Django?

A {% raw %}{% include 'base.html' %}{% endraw %}

B {% raw %}{% block 'base.html' %}{% endraw %}

C {% raw %}{% extends 'base.html' %}{% endraw %}

D {% raw %}{% import 'base.html' %}{% endraw %}

The {% raw %}{% extends %}{% endraw %} tag is used to inherit from a base template.

What does the {% raw %}{% block %}{% endblock %}{% endraw %} tag do in a base template?

A Defines a section that child templates can override

B Includes another template

C Adds a comment

D Starts a loop

Blocks mark sections in the base template that child templates can replace with their own content.

If a child template does not override a block, what content is shown?

A The block content from the base template

B An error is shown

C The block is empty

D The child template content is shown

The base template's block content acts as default if the child does not override it.

Where should the {% raw %}{% extends %}{% endraw %} tag be placed in a Django template?

A Anywhere in the template

B At the very top of the template

C Inside a block

D At the bottom of the template

The {% raw %}{% extends %}{% endraw %} tag must be the first tag in the template.

What is a key benefit of using template inheritance?

A Automatically styling pages

B Making templates run faster

C Adding JavaScript functionality

D Reusing common layout and reducing repeated code

Template inheritance helps reuse layout and avoid repeating the same HTML in many files.

Explain how template inheritance works in Django using a base template and child templates.

Think about how a master page sets the frame and others fill in details.

Describe why using a base template with blocks is better than copying the same HTML in every page.

Imagine changing a header on 100 pages vs just one file.

Practice

1. What is the main purpose of using {% extends %} in a Django template?

easy

A. To define a new block inside the template

B. To include JavaScript files in the template

C. To inherit the layout and content from a base template

D. To load static files like images or CSS

Solution

1. Step 1: Understand the role of {% extends %}

   This tag tells Django to use another template as the base layout for the current template.

2. Step 2: Compare with other options

   Options B, C, and D describe different template tags or functions unrelated to inheritance.

3. Final Answer:

   To inherit the layout and content from a base template -> Option C

4. Quick Check:

   {% extends %} = inherit base template [OK]

Hint: Remember: extends means 'use base template' [OK]

Common Mistakes:

• Confusing extends with include
• Thinking extends loads static files
• Mixing block and extends tags

2. Which of the following is the correct syntax to define a block named 'content' in a Django template?

easy

A. {% content block %} ... {% endcontent %}

B. {% block 'content' %} ... {% endblock %}

C. {% define content %} ... {% enddefine %}

D. {% block content %} ... {% endblock %}

Solution

1. Step 1: Recall block syntax in Django templates

   The correct syntax uses {% block blockname %} and closes with {% endblock %} without quotes.

2. Step 2: Check each option

   {% block content %} ... {% endblock %} matches the correct syntax. Options A, C, and D use invalid tags. {% block 'content' %} ... {% endblock %} incorrectly uses quotes around the block name.

3. Final Answer:

   {% block content %} ... {% endblock %} -> Option D

4. Quick Check:

   Block syntax = {% block name %} ... {% endblock %} [OK]

Hint: Blocks never use quotes around their names [OK]

Common Mistakes:

• Adding quotes around block names
• Using wrong tag names like define or content block
• Forgetting to close the block with endblock

3. Given the base template

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

and a child template

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

, what will be the rendered output for the content block when rendering the child template?

medium

A. Base Content

B. Child Title

C. Child Content

D. Empty content block

Solution

1. Step 1: Understand block overriding in inheritance

   The child template overrides only the title block, so the content block remains as defined in the base template.

2. Step 2: Determine output for content block

   Since the child does not override content, the base template's Base Content is used.

3. Final Answer:

   Base Content -> Option A

4. Quick Check:

   Unchanged blocks show base content [OK]

Hint: Only overridden blocks change output [OK]

Common Mistakes:

• Assuming all blocks are replaced
• Confusing title block content with content block
• Expecting empty output if block not overridden

4. Identify the error in this child template code:

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

medium

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

B. Missing {% load static %} tag

C. The extends tag must be at the end of the file

D. Block name 'content' is invalid

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: Verify other options

   Missing {% load static %} tag is unrelated to block syntax. The extends tag must be at the end of the file is false; extends must be at the top. Block name 'content' is invalid is incorrect; 'content' is a valid block name.

3. Final Answer:

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

4. Quick Check:

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

Hint: End blocks with just {% endblock %} [OK]

Common Mistakes:

• Adding block name after endblock
• Placing extends tag incorrectly
• Confusing load static with block syntax

5. You have a base template with blocks header, content, and footer. You want a child template to reuse the base layout but add a sidebar inside the content block without losing the original content. Which is the correct way to do this?

hard

A. {% raw %}{% extends 'base.html' %}{% block sidebar %}Sidebar content{% endblock %}{% endraw %}

B. {% raw %}{% extends 'base.html' %}{% block content %}{{ block.super }}Sidebar content{% endblock %}{% endraw %}

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

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

Solution

1. Step 1: Understand how to keep base content in a block

   Using {{ block.super }} inside a block includes the original content from the base template's block.

2. Step 2: Analyze options

   {% raw %}{% extends 'base.html' %}{% block content %}{{ block.super }}
   Sidebar content{% endblock %}{% endraw %} correctly adds sidebar content after the original content. Options B and D replace the content entirely. {% raw %}{% extends 'base.html' %}{% block sidebar %}Sidebar content{% endblock %}{% endraw %} tries to add a new block 'sidebar' which doesn't exist in base, so it won't appear.

3. Final Answer:

   {% extends 'base.html' %}{% block content %}{{ block.super }}
   Sidebar content
   {% endblock %} -> Option B

4. Quick Check:

   Use {{ block.super }} to keep base block content [OK]

Hint: Use {{ block.super }} to keep base block content [OK]

Common Mistakes:

• Overwriting block content without block.super
• Adding blocks not defined in base template
• Forgetting to extend the base template