Django (template language - custom filter and simple_tag)

a. Create templatetags module in app (required)

b. Create a .py file in templatetags, such as my_tags.py

from django import template
from django.utils.safestring import mark_safe

register = template.Library()    # The name of the register is fixed and cannot be changed


@register.filter
def filter_multi(v1,v2):
    return  v1 * v2


@register.simple_tag            
def simple_tag_multi(v1,v2):
    return  v1 * v2


@register.simple_tag
def my_input(id,arg):
    result = "<input type='text' id='%s' class='%s' />" %(id,arg,)
    return mark_safe(result)

c. Import the previously created my_tags.py in html: {% load my_tags%}

d. Use filter and simple_tags (how to call)

-------------------------------.html
{% load xxx %} #First line
    
    
    
    
 # num=12
{{ num|filter_multi:2 }} #24 The maximum number of parameters is 2, but they can be placed in the if for statement

{{ num|filter_multi:"[22,333,4444]" }}


{% simple_tag_multi 2 5 %} The parameters are not limited, but they cannot be placed in the if for statement
{% simple_tag_multi num 5 %}

e. Configure the current app in INSTALLED_APPS in settings, otherwise django cannot find the custom simple_tag

Note: (filter can be placed in an if for statement, simple_tags cannot)

{% if num|filter_multi:30 > 100 %}
    {{ num|filter_multi:30 }}
{% endif %}