A category list.

I think it’s best to use Django‘s template tags for this job, as my template tag currently has to do one simple thing:

Return all existent categories(no matter if they have or not have references to any blog post).

I start doing this by creating a folder named templatetags in my blog application.

Never forget the __init__.py

Then I’ll go and create a file called get_category_list.py, the template tag file itself.

# -*- mode: python; coding: utf-8; -*-

from django import template
from blog.models import Post, Category

register = template.Library()

def category_list():
    categories = Category.objects.all()
    return {'categories': categories}

 register.inclusion_tag('templatetags/category_list.html')(category_list)

I think it’s very self-explanatory. I create a function which returns a dictionary containing a Category object dictionary, containing all existing categories. You can specify that behavior by .filter() it or write a custom manager. You get the point.

Now the interesting part is the last line. We decorate our function with the register.inclusion_tag() decorator. Why using inclusion_tag? you may ask. Well I use it here for a certain convenience for later including the category_list.html in any template I’d like and writing less code, which means better quality to me.

Next step from here is to create the category_list.html in your templatetags folder.

Writing the content is dead simple. It may look like this:

<ul id="category-list">
{% for category in categories %}
    <li class="align_center">
        <a href="{% url whatever_reverse_url %}" title="{{ category.title }}">
            {{ category.title }}
        </a>
    </li>
{% endfor %}
</ul>

and the last step is to include this anywhere in your templates.

{% load get_category_list %}
    <header>
    <h2>Categories</h2>
    {# category_list was added to the template's context #}
    {% category_list %}
    </header>

In the next part, I’ll eventually show you how to get to number of posts with the category name.

Be sure to leave a comment!