give an active to class to active link

Question

Hello,

I am writing a python website built on the back of the django framework, I am looking for a way to highlight the current link the user is on depening on what the URL, I thought doing some thing like this would work.

What I have done is create a new application called nav and built some templatetags, like so,

from django import template

register = template.Library()

URL_PATTERNS = {
    'home': (r'^/$',),
}

@register.tag
def nav_selection(parser, token):
    try:
        tag_name, nav_item = token.split_contents()
    except ValueError:
        raise template.TemplateSyntaxError, "%r tag requires a single argument" % token.contents.split()[0]
    if not (nav_item[0] == nav_item[-1] and nav_item[0] in ('"', "'")):
        raise template.TemplateSyntaxError, "%r tag's argument should be in quotes" % tag_name
    return NavSelectionNode(nav_item[1:-1])

class NavSelectionNode(template.Node):
    def __init__(self, nav_item):
        self.nav_item = nav_item
    def render(self, context):
        if not 'request' in context:
          return "" 
        import re
        try:
            regs = URL_PATTERNS[self.nav_item]
        except KeyError:
            return ''
        for reg in regs:
            if re.match(reg, context['request'].get_full_path()):
                return "active"
        return ''

In my template I do this

<ul id="navigation">{% load nav %}
    <li><a href="{% url views.home %}" class='{% nav_selection "home" %}'>home</a></li>
    <li><a href="{% url views.about %}" class='{% nav_selection "about" %}'>about neal &amp; wolf</a></li>
    <li><a href="{% url shop.views.home %}" class='{% nav_selection "shop" %}'>our products</a></li>
    <li><a href="{% url shop.views.home %}" class='{% nav_selection "shop" %}'>shop</a></li>
    <li><a href="{% url views.look %}" class='{% nav_selection "look" %}'>get the look</a></li>
    <li><a href="{% url news.views.index %}" class='{% nav_selection "news" %}'>news</a></li>
    <li><a href="{% url contact.views.contact %}" class='{% nav_selection "contact" %}'>contact us</a></li>
    <li><a href="{% url store_locator.views.index %}" class='{% nav_selection "finder" %}'>salon finder</a></li>
    <li><a href="{% url professional.views.index %}" class='{% nav_selection "contact" %}'>neal &amp; wolf professional</a></li>

   </ul>

yet the markup I get out in firebug is this in this example I am browsing the index page

<a class="" href="/home/">

So something is obviously failing but I cannot see where, can anyone help me please?

Answer 1

Some things to check:

Is the request object actually in your context? Are you passing it in specifically, or are you using a RequestContext?

Why are you defining regexes in your templatetags, rather than using the built-in reverse function to look them up in the urlconf?

Do the regexes here actually match the ones in the urlconf?

Have you included your home urlconf under the 'home' url somehow?