Django template tag to encode an image to a base64 data-uri

data_uri.py

from urllib.parse import urlparse

from django import template
from django.template.defaultfilters import stringfilter
from base64 import b64encode
import requests
from django.core.cache import cache


register = template.Library()

@register.filter(is_safe=True)
@stringfilter
def dataURI(url):

    parts = urlparse(url)
    domain = parts.netloc
    encoded = cache.get(f'image-{url}')

    if not encoded:
        r = requests.get(url)
        encoded = b64encode(r.content).decode()
        cache.set(f'favicon-{domain}', encoded, None)

    return f"data:image/png;base64,{encoded}"