Data URI for template images

datalize.py

# templatetags/dataURI.py

from mimetypes import guess_type

from django import template
from base64 import b64encode
from django.contrib.staticfiles import finders

register = template.Library()


@register.filter
def datalize(filename, content_type=None):
    """
    This filter will return data URI for given file, for more info go to:
    http://en.wikipedia.org/wiki/Data_URI_scheme
    Sample Usage:
    <img src="{{ 'image.jpg'|datalize }}"/> or 
    <img src="{% static 'image.jpg'|datalize %}"/>
    will be filtered into:
    <img src="data:image/png;base64,iVBORw0...">
    """
    if filename:
        with open("static/" + filename, "rb") as f:
            data = f.read()

        encoded = b64encode(data)
        content_type, encoding = guess_type(filename)
        return "data:%s;base64,%s" % (content_type, encoded)
    else:
        return ''


@register.simple_tag
def data_url(path, content_type=None):
    '''
    Return a media url of this file

    Use just like the {% static %} tag.

        {% data_url "img/hamburger.jpg" %}

    Optionally override the content type:

        {% data_url "img/hamburger.jpg" content_type="text/plain" %}

    '''
    result = finders.find(path)
    if result:
        if not content_type:
            content_type, encoding = guess_type(result)
            # if no content_type, force below content_type
            content_type = content_type or 'application/octet-stream'
        with open(result, 'rb') as f:
            return 'data:%s;base64,%s' % (
                content_type,
                b64encode(f.read()),
            )
    else:
        return ''