Django Template Tag Inheritance How-to

Posted by Alexander Todorov on Sun 22 December 2013

While working on open-sourcing Difio I needed to remove all hard-coded URL references from the templates. My solution was to essentially inherit from the standard {% url %} template tag. Here is how to do it.

Background History

Difio is not hosted on a single server. Parts of the website are static HTML, hosted on Amazon S3. Other parts are dynamic - hosted on OpenShift. It's also possible but not required at the moment to host at various PaaS providers for redundancy and simple load balancing.

As an easy fix I had hard-coded some URLs to link to the static S3 pages and others go link to my PaaS provider.

I needed a simple solution which can be extended to allow for multiple domain hosting.

The Solution

The solution I came up with is to override the standard {% url %} tag and use it everywhere in my templates. The new tag will produce absolute URLs containing the specified protocol plus domain name and view path. For this to work you have to inherit the standard URLNode class and override the render() method to include the new values.

You also need to register a tag method to utilize the new class. My approach was to use the existing url() method to do all background processing and simply casting the result object to the new class.

All code is available at

To use in your templates simply add

{% load fqdn_url from fqdn_url %}
<a href="{% fqdn_url 'dashboard' %}">Dashboard</a>

tags: Django

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