Django template blocks: how can i reuse them and how do i pass HTML into them? - django

Question

Being a frontend dev familiar with Ruby, i'm trying to learn Django templating system.
It appears to be an inside-out version of what i'm used to. I struggle to comprehend its reverse ideology: instead of declaring reusable blocks and including them where necessary, in Django you mark some parts of your template as overridable.
Here are two things that i don't understand about this.
With Ruby's Padrino, i would declare a partial (a reusable snippet of templated HTML) and then include it in multiple places. Wherever i call it, it would output its HTML.
According to Django's templating documentation, each block can be used on a page only once: Finally, note that you can’t define multiple block tags with the same name in the same template.
Another feature of Padrino that i find extermely useful is that partials can accept HTML and output (yield) it in a certain place inside them. Below are a couple examples, one for Padrino and one for Jade.
Please note that partails HTML not as a string (awkwardly passed via an argument) but in a template language via nesting.
Padrino (Ruby) example
With Padrino i can pass HTML template code into partials:
_container.erb
<div class="container <%= myclass %>">
<div class="container-inner">
<%= yield %>
</div>
</div>
layout.erb
<%= partial 'container', locals: { myclass: 'container--header' } do %>
<h1><%= Sitename %></h1>
<p>Welcome to my humble place</p>
<% end %>
Resulting HTML
<div class="container container--header">
<div class="container-inner">
<h1>Sitename</h1>
<p>Welcome to my humble place</p>
</div>
</div>
Jade example
In Jade, partials are called mixins and are processed directly by the template engine rather than the backend framework:
Jade source
mixin article(title)
.article
.article-wrapper
h1= title
if block
block
else
p No content provided
+article('Hello world')
p This is my
p Amazing article
Resulting HTML
<div class="article">
<div class="article-wrapper">
<h1>Hello world</h1>
<p>This is my</p>
<p>Amazing article</p>
</div>
</div>
Is it possible with Django?
Questions:
How do i reuse a block multiple times in Django? I would like to declare a snippet of template code and include it in multiple places on the page.
How do i pass HTML (template code) into a block? I would like to reuse it with different content.
The use case that i'm trying to cover is a reusable partial/mixin/block that would serve as a container wrapper for each section of the site.
Note that with Padrino, i can even make the partial in such a way that it will let me choose which wrapper tag (div, nav, header...) should be used for each instance of the partial, by passing an argument when including the partial:
<% partial 'container', myclass: 'container--header', tag: 'nav' %>
I wonder how to do that with Django.
In your answer, please comment on whether it is possible with both a) basic Django functionality; b) some Django extensions.
Thank you.

Answer 1

I’m not familiar with Padrino, so I’m not 100% sure I understand what you’re looking for.
However, Django template blocks definitely aren’t the equivalent of Padrino’s partials. From your description, I think the equivalent would be custom template tags.
In outline, to create a custom template tag, you:
Create a templatetags module within your Django app, with a file in it to contain the Python code for the tags e.g.
yourapp/
models.py
templatetags/
__init__.py
mytemplatetags.py
Within that file, create a variable called register that’s an instance of django.template.Library:
# mytemplatetags.py
from django import template
register = template.Library()
Within that file, write a function for each custom tag that you want.
For a tag that includes a template snippet, you’d want to write an inclusion tag.
Inclusion tags can take arguments, which could include HTML (but only as a string).