Django tag for relative urls

Question

I want to write a custom url templatetag, that would also work with relative paths (and not only named patterns) and accepts list in arguments (which are later used to call a different view function - that's why I need the request object). This is my tag in template :

{% with '/views' (normally it's a var created in for loop) as link %}
    <a href="{% url_for link params=('website','homepage') %}">Click</a>
{% endwith %}

and tag's code itself :

@register.simple_tag(takes_context = True)
def url_for(context, parser, token):
    request = context['request']
    bits = token.split_contents()
    if len(bits) < 2:
        raise TemplateSyntaxError("'%s' takes at least one argument"
                                  " (path to a view)" % bits[0])
    try:
        if "/" in bits[1]:
            bits[1] = unicodedata.normalize('NFKD', bits[1]).encode('utf-8', 'ignore')
            try:
                bits[1] = resolve(bits[1].replace("'","")).url_name
            except Exception as e:
                log.error('Exception when resolving url for tag: %s' % e)

        viewname = bits[1]
    except Exception as exc:
        raise

    args = []
    kwargs = {}
    asvar = None
    bits = bits[2:]

    if len(bits):
        for bit in bits:
            if 'params' in bit:
                par = ast.literal_eval(bit.split('=')[1])
                my_function(request, par[0], par[1])
                break

    from django.core.urlresolvers import reverse, NoReverseMatch

    url = ''
    try:
        url = reverse(viewname, args=args, kwargs=kwargs, current_app=context.current_app)
    except NoReverseMatch:
        exc_info = sys.exc_info()
        if settings.SETTINGS_MODULE:
            project_name = settings.SETTINGS_MODULE.split('.')[0]
            try:
                url = reverse(project_name + '.' + view_name,
                          args=args, kwargs=kwargs,
                          current_app=context.current_app)
            except NoReverseMatch:
                    six.reraise(*exc_info)
        else:
            raise

    return url

Unfortunately right now the only thing I was able to achieve is TemplateSyntaxError at /: Could not parse the remainder: '('website','homepage')' from '('website','homepage')' . Before that I was trying to monkeypatch the original url tag and URLNode but I had a bunch of different problems there. Any help with tackling this appreciated.

Answer 1

Template files are not Python. Thus, you can't do the tuple thing with your arguments. Instead, refactor the template tag to take this type of syntax:

{% url_for link params='website homepage' %}

Then you have to account for that when parsing the bits variable in the template tag. It ultimately comes down to parsing strings.

The docs:

https://docs.djangoproject.com/en/dev/howto/custom-template-tags/#writing-the-compilation-function

See the notes for "token.contents" and "token.split_contents()".