Sometimes existing templates tags are not enough for rebellious developers. They need to create custom template tags to use.

In this article, we are discussing step by step process to create and use custom template tags in Django.

Template Tags:

Steps to create custom template tags:

• Create a new directory inside your app and name it 'templatetags'.
• Create the __init__.py  file inside this newly-created directory.
• Create tags file. Lets name is custom_template_tag.py.
• Import template.
• All the tags should be registered to template.library instance.
• For registering tags, create a module-level variable, lets name it library. So on the top of the file, after import statements write register = template.library() .
• Now let's create a very simple tag to get a random number in the template. For this, you need to import randint.
• write code to generate a random number and register that function with the library. The complete code should look like below.
  
  

from django import template
from random import randint


register = template.Library()


@register.simple_tag
def random_number():
    return randint(0,999)

How to use a custom tag in Django templates:

Load the tag class in your template before using any template. {% load custom_template_tags %}

Now use custom tag anywhere in your HTML. {% random_number %} .

This will print a random number at the same place. you can store the output of tag in some variable can use to anywhere in the template. {% random_number as rnd %}. Now anywhere in template use {{rnd}} .

Things to take care of to make custom tags work:

• Make sure you restarted the development server.
• The directory name must be templatetags.
• __init__.py  must be present in the directory.
• App, where the templatetags directory is created, must be present in installed apps.
• Load the tag file in the template file where the tag will be used. Loading file in parent template and then expecting it would be available to all child templates, would not work. Because zen of python.
• If tag still not working, remove all .pyc  files.

If it is still not working for you, please comment.