Question

I’m getting a strange error with my URLconf.

I’ve got the following setup.

# root conf
urlpatterns = patterns('',
    # ...
    url(r'^cart/', include('bbhq.cart.urls')),
    # ...
)

# bbhq.cart.urls
urlpatterns = patterns('',
    # ...
    url(r'^add_to_cart$', add_to_cart, name='add-to-cart-page'),
    # ...
)

I have a form that uses the reverse function (successfully)

<form method="post" action="{% url add-to-cart-page %}">

However I’m getting a 404 page not found when I submit the form.

I can’t work out what’s going on here. How can the reverse function work but give me a 404 on the actual url?

I don’t know if it’s relevant but the debug info on the 404 doesn’t show the list of regex searched as it often does in these situations. This is all I get –

Page not found (404)
Request Method: POST
Request URL:    http://192.168.1.98:8000/cart/add_to_cart

My view code is –

def add_to_cart(request):
    if request.method == 'POST':
        if 'cart' in request.session:
            cart = request.session['cart']
        else:
            cart = Cart()
        if 'item_id' not in request.POST:
            raise Http404
        else:
            try:
                item = StockItem.objects.get(pk=int(request.POST['item_id']))
            except:
                raise Http404
            cart_add(cart, item)
            request.session.modified = True
        if request.is_ajax():
            return render_to_response('cart/cart_summary.html',
                                      {'cart_count': cart_items(cart),
                                       'cart_total': cart_total(cart)},
                            context_instance=RequestContext(request))
        else:
            return HttpResponseRedirect(reverse('cart-page'))
    else:
        raise PermissionDenied

I’ve also tried appending a slash to the url but I get exactly the same error –

url(r'^add_to_cart/$', add_to_cart, name='add-to-cart-page'),

Answer 1

When you receive a standard 404 (one without the stacktrace) it usually means it executed your raise Http404(). I suggest you use the messages and redirects instead to make things a little easier on your users as well as yourself:

def add_to_cart(request):
    if request.method == 'POST':
        if 'cart' in request.session:
            cart = request.session['cart']
        else:
            cart = Cart()
        if 'item_id' not in request.POST:
            '''
            HERE BE CHANGES
            '''
            # The id was not supplied
            messages.error(request, 'No item was provided')
            return HttpResponseRedirect(request.META['HTTP_REFERER'])
        else:
            try:
                item = StockItem.objects.get(pk=int(request.POST['item_id']))
            except:
                '''
                HERE BE CHANGES
                '''
                # The item was not found in the database
                messages.error(request, 'Unable to find the specified item.'
                return HttpResponseRedirect(request.META['HTTP_REFERER'])
            cart_add(cart, item)
            request.session.modified = True
        if request.is_ajax():
            return render_to_response('cart/cart_summary.html',
                                      {'cart_count': cart_items(cart),
                                       'cart_total': cart_total(cart)},
                            context_instance=RequestContext(request))
        else:
            return HttpResponseRedirect(reverse('cart-page'))
    else:
        raise PermissionDenied