Structure in the flow

I’m working on a project based on Django, these days. This framework simplifies developing web applications by a great measure, and is very flexible.

One example of this flexibility is the ability to add new functionality to template syntax. For example, I needed a way to display a date/time as a difference to the current one (“19 days ago”, “10 hours ago”).

Turns out there’s a way to do this in Django: as soon as a need can be generalized, it’s probably in there somewhere, or on djangosnippets. It’s the template filter “timesince“. Basically, in the template, you do:

{{ mydate|timesince }} ago

and it will display your date as said above. Problem is, the string is too long for my needs (it will display “19 days, 10 hours” when I need only “19 days”). So I wrapped the function in another one, in a file place under an app of my project, as explained here. Here’s the content:

from django import template
from django.utils.timesince import timesince

register = template.Library()

@register.filter(name='ago')

def ago(date):

    ago = timesince(date)

    # selects only the first part of the returned string

    return ago.split(",")[0] + " ago"

I place that under “myproject/myapp/templatetags/my_date_filter.py”. I also created an empty file __init__.py under templatetags, too. Then, in the template, I may do:

{% load my_date_filter %}
...
{% mydate|ago %}

and I get the shortened string.

Django is full of “extension points” like such. It’s a lot of fun to work with.