Reverse for Model with Slug in URL not working - django

Question

I have a parts.html page that references the model Part, the page I am having issue with is the Part List Generic Model view. The purpose of it is to list all of the parts on a page and show the category next to it. Each part has a foreignkey "category". I am trying to create a Slug URL from the Part list view to the Category detail page, but I receive this error when I go to the partlistview page. I can access the Category page with portal/category/category where the second category at the end is a category in the database.
Note: The entire python files below are to scale, I only pasted in relevant information, as it would be too much info.
django.urls.exceptions.NoReverseMatch: Reverse for 'category-detail' with arguments '('',)' and keyword arguments '{}' not found. 1 pattern(s) tried: ['portal/category/(?P<slug>[-\\w]+)/$']
Views.py
class PartDetailView(LoginRequiredMixin, generic.DetailView):
model = Part
template_name = 'portal/part.html' # Option - Specify your own template name/location
class PartListView(LoginRequiredMixin, generic.ListView):
model = Part
#queryset = Part.objects.filter(is_active=True) #.prefetch_related('user') #hos
paginate_by = 100
https://simpleisbetterthancomplex.com/tutorial/2017/03/13/how-to-create-infinite-scroll-with-django.html
template_name = 'portal/parts.html' # Option - Specify your own template name/location
context_object_name = 'part_list'
#def get_queryset(self):
#return Category.objects.all()
def get_context_data(self, **kwargs):
context = super(PartListView, self).get_context_data(**kwargs)
context['category'] = Category.objects.all()
return context
class CategoryDetailView(LoginRequiredMixin, generic.DetailView):
model = Category
template_name = 'portal/category.html' # Option - Specify your own template name/location
slug_field = 'category'
slug_url_kwarg = 'category'
Models.py
#python_2_unicode_compatible
class Category(BaseModel):
"""
Model representing a part type (wiper, wheel, brake).
"""
id = models.BigAutoField(primary_key=True)
category = models.CharField(max_length=120, help_text=_("Category to organize parts into (wheel, wiperblade, brake)"))
slug = models.SlugField(editable=False, unique=True, db_index=True)
def __str__(self):
return '%s' % (self.category)
def get_absolute_url(self):
return reverse('portal:category-detail', kwargs={'slug': self.slug}) # str(self.trailer_number) kwargs={'slug': self.slug} instead of args=[self.slug]??
def save(self, *args, **kwargs):
self.slug = slugify(self.category)
super(Category, self).save(*args, **kwargs)
class Meta:
db_table = 'category'
verbose_name = _('category')
verbose_name_plural = _('categories')
ordering = ['category']
#python_2_unicode_compatible
class Part(BaseModel):
id = models.BigAutoField(primary_key=True)
name = models.CharField(max_length=120, help_text=_("The unique name or part number to identify this particular item"))
category = models.ForeignKey(Category, on_delete=models.PROTECT, help_text='Category to organize parts into (wheel, wiperblade, brake)', related_name='part', null=True, blank=True)
brand = models.CharField(max_length=80, blank=True, help_text=_("The name of the manufacturer that originaly built this part"), null=True)
minimum_inventory_quantity = models.PositiveSmallIntegerField(default=0, help_text=_("The minimum inventory quantity of this part before more need to be ordered"))
def get_absolute_url(self):
return reverse('portal:part-detail', args=[str(self.id)])
def __str__(self):
return '%s - %s' % (self.name, self.brand)
class Meta:
unique_together = ("name", "brand",) #NOTE: Each SKU + Carrier should also be unique together #unique_together = (("name", "manufacturer"), ("sku", "Carrier"))
ordering = ["name", "brand",]
Urls.py
from django.conf.urls import url
from .views import PartDetailView, CategoryDetailView, PartListView, PartInstanceDetailView, PartVariantDetailView
urlpatterns = [
url(r'^parts/$', PartListView.as_view(), name='parts'),
url(r'^parts/(?P<pk>\d+)/$', PartDetailView.as_view(), name='part-detail'),
url(r'^category/(?P<slug>[-\w]+)/$', CategoryDetailView.as_view(), name='category-detail'),
]
parts.html
<div class="table-responsive">
<table class="table table-hover table-bordered table-striped">
<thead>
<tr>
<th>Category</th>
<th>Name</th>
<th>Brand</th>
<th>Model Number</th>
<th>Variants</th>
<th>Stock</th>
<th>Locations</th>
</tr>
</thead>
<tbody>
{% for part in part_list %}
<tr>
<td><strong>{{ part.category.category }}</strong></td>
<td><a href="{% url 'portal:part-detail' part.pk %}">{{ part.name }}</td>
<td>{{ part.brand }}</td>
<td>{{ part.part_variant.model_number }}</td>
<td>{{ part.count_all }}</td>
<td>{{ part.count_all }}</td>
<td>{{ part.section.zone }}</td>
</tr>
{% empty %}
{% if request.GET.q %}
<tr>
<td colspan="7" class="text-center bg-warning">No trailers found.</td>
</tr>
{% else %}
<tr>
<td colspan="7" class="text-center bg-warning">There are no trailers in the system.</td>
</tr>
{% endif %}
{% endfor %}
</tbody>
</table>
</div>

Answer 1

I'm not entirely sure but I think your urls.py need an app_name = portal before the urls list.
Read up more in the docs.

Answer 2

Your url pattern is expecting a keyword argument, but the url template tag is passing the category slug as an unnamed argument.
Just do this {% url "portal:category-detail" slug=category.slug %},
because in your url pattern you named your capture group "slug".
Also, make sure category.slug is actually returning something.