NoReverseMatch at/ 带有 slug 的 url 有问题

Question

我收到NoReverseMatch at /:

找不到带有参数“（u”，）和关键字参数“{}”的“类别”。尝试了 1 种模式：['category/(?P[\w\-]+)/$']

我不确定哪里出错了。我知道它是哪里引起的，但我不知道为什么。此网址导致错误：

url(r'^category/(?P<category_name_slug>[\w\-]+)/$', views.category, name='category'),

并且错误来自这个 index.html

{% for category in categories %}
    <li class="list-group-item"><a href="{% url 'category' category.slug %}">{{ category.name }}</a></li>
{% endfor %}

我很确定我的 views.py 没有任何问题，但以防万一我会把它贴在这里

    #for front page

def index(request):
        """This view return index page. In index page, there is thread list.
        And thread list can be sorted by score, number of comment, date, title using paging.
        GET parameters are 'sort' and 'page'. 'sort' is sorting methods. 'page' is number of page.
        :param request: Django request object
        :return: Thread list page
        """

        categories = Category.objects.all()

        try:
                sort = request.GET["sort"].strip()
                sort_method = SortMethods[sort]
                page = request.GET["page"].strip()
        except KeyError:
                sort_method = SortMethods.score
                page = 1

        if sort_method == SortMethods.date:
                thread_list = Post.objects.order_by("-pub_date")
        else:
                thread_list = Post.objects.all()
                thread_list = sorted(thread_list, key=lambda x: x.get_score(), reverse=True)

        paginator = Paginator(thread_list, 30)

        try:
                posts = paginator.page(page)
        except PageNotAnInteger:
                posts = paginator.page(1)
        except EmptyPage:
                posts = paginator.page(paginator.num_pages)

        context = {
                "posts": posts,
                "pages": paginator.page_range,
                "sort": sort_method.name,
                "categories":categories
        }
        return render(request, "main/index.html", context)

#for single-post page
def post(request, slug):
        single_post = get_object_or_404(Post, slug=slug)
        single_post.views += 1  # increment the number of views
        single_post.save()      # and save it
        context_dict = {
            'single_post' :single_post,
        }

        return render(request, 'main/post.html', context_dict)
#for category page
def category(request, category_name_slug):
    try:

                category = Category.objects.get(slug=category_name_slug)
                sort = request.GET["sort"].strip()
                sort_method = SortMethods[sort]
                page = request.GET["page"].strip()
    except KeyError:
                sort_method = SortMethods.score
                page = 1

    if sort_method == SortMethods.date:
                thread_list = Post.objects.filter(category=category).order_by("-pub_date")
    else:
                thread_list = Post.objects.filter(category=category)
                thread_list = sorted(thread_list, key=lambda x: x.get_score(), reverse=True)

    paginator = Paginator(thread_list, 30)

    try:
                posts = paginator.page(page)
    except PageNotAnInteger:
                posts = paginator.page(1)
    except EmptyPage:
                posts = paginator.page(paginator.num_pages)

    context = {
                "posts": posts,
                "pages": paginator.page_range,
                "sort": sort_method.name,
                "categories":category,
              "cat_name_slug":category_name_slug,
        }
    return render(request, "main/index.html", context)

Answer 1

首先要注意的是，您有一个 空弹头：

使用参数 '(u'',)' 和关键字参数 '{}' 未找到的“类别”反转

一个问题是你如何定义categories - .all() 是一个方法，调用它：

categories = Category.objects.all()
                             HERE^

此外，您应该检查您的类别是否生成了非空 slug。