Django generic helpers template tags

common_tags.py

# -*- coding: utf-8 -*-
#
# No Rights Reserved
# http://creativecommons.org/publicdomain/zero/1.0/

from __future__ import unicode_literals
from urllib.parse import urlencode, parse_qs, urlsplit, urlunsplit
from django.template import Library
from django.utils.safestring import mark_safe

register = Library()


@register.filter
def str_format(val, arg):
    return val.format(arg)


@register.filter
def str_count(var, sub):
    return var.count(sub)


@register.filter
def str_strip(var, symbols):
    return var.strip(symbols) if var else var


@register.filter
def nbsp(val):
    return mark_safe(val.replace(' ', ' '))


@register.filter
def is_between(val, minmax):
    if minmax:
        return (val >= minmax[0] and val <= minmax[1])
    return False


@register.filter
def is_checkbox(field):
    return 'type="checkbox"' in str(field)


@register.filter
def try_key(val, key):
    return val.get(key)


@register.filter
def try_first(val):
    if val:
        return val[0]


@register.filter
def site_url(request):
    return request.build_absolute_uri('/').strip('/')


@register.assignment_tag
def set_param(url, name, value):
    """Set new attribute to URL query.
    """
    scheme, netloc, path, query, fragment = urlsplit(url)
    query_params = parse_qs(query)

    query_params[name] = [value]
    new_query = urlencode(query_params, doseq=True)

    return urlunsplit((scheme, netloc, path, new_query, fragment))