In django how know if a url is part of urlpatterns config?

Question

I build a dynamic breadcumb, and some parts of it are not valid urls (are not in urlpatterns).

I have this templatetag:

@register.filter
def crumbs(url):
    "Return breadcrumb trail leading to URL for this page"
    l = url.split('/')
    urls = []
    path = ""
    for index, item in enumerate(l):
        if item == "":
            continue
        path += item + "/"
        urls.append({'path':path,'name':item})

Now, I want to check if that specific URL is a valid url, ie, have a key in urlpatterns (of curse I will need to change my templatetag).

Something like:

IsInUrlPattern('/') => True
IsInUrlPattern('/blog/2004/') => True
IsInUrlPattern('/blog/thisfail/') => False

Answer 1

You want the resolve() function.