unindent_tags.py

from django.template.base import Node, Library

register = Library()


class UnindentNode(Node):
    def __init__(self, nodelist):
        self.nodelist = nodelist

    def render(self, context):
        lines = self.nodelist.render(context).split('\n')
        return '\n'.join(line.strip() for line in lines)


@register.tag
def unindent(parser, token):
    nodelist = parser.parse(('endunindent',))
    parser.delete_first_token()
    return UnindentNode(nodelist)