Cannot resolve keyword u'slug' into field error in Django? - django

Question

I am getting the following error:
FieldError at /blog/1/first-post/
Cannot resolve keyword u'slug' into field. Choices are: article, date, id, likes
Request Method: GET
Request URL: http://127.0.0.1:8000/blog/1/first-post/
Django Version: 1.6.2
Exception Type: FieldError
Exception Value:
Cannot resolve keyword u'slug' into field. Choices are: article, date, id, likes
My model:
class Article(models.Model):
title = models.CharField(max_length=20)
body = models.TextField()
image = models.ImageField(upload_to="/", blank=True, null=True)
slug = models.SlugField()
def save(self, *args, **kwargs):
if not self.id:
self.slug = slugify(self.title)
super(Article, self).save(*args, **kwargs)
def get_absolute_url(self):
return reverse('article_detail', kwargs={'slug':self.slug, 'id':self.id})
def __unicode__(self):
return self.title
class Detail(models.Model):
article = models.ForeignKey(Article)
date = models.DateField()
likes = models.IntegerField()
def __unicode__(self):
return "%s %s" % (self.article.title, self.likes)
def get_absolute_url(self):
return reverse('detail_article', kwargs={'id':self.id})
View:
class ArticleDetail(DetailView):
model = Detail
template_name = "article_detail.html"
context_object_name = "details"
def get_queryset(self):
print self.kwargs['slug']
a = Article.objects.get(slug=self.kwargs['slug'])
# print Details.object.get()
# print Detail.objects.filter(article__slug=self.kwargs['slug']) fails with same error
return Detail.objects.filter(article=a)
urls.py (this is inside by blog app):
urlpatterns = patterns('',
url(r'all$', ArticleList.as_view(), name='blog_all'),
url(r'^(?P<id>\d+)/(?P<slug>[-\w\d]+)/$', ArticleDetail.as_view(), name='article_detail'),
url(r'^detail/?(P<id?\d+)/$', DetailArticle.as_view(), name='detail_article'),
url(r'^create$', ArticleCreateView.as_view(), name='blog_create'),
)
Basically the detailView of an article instance will display the contents of detail model that has foreignkey relationship to article model. It is not the traditional way where the detail view of article instance displays that instance.
Template here:
{% extends "base.html" %}
{% block content %}
{% for detail in details %}
<p>{{ detail.article.title }}</p>
<p>{{ detail.date }}</p>
<p>{{ detail.likes }}</p>
{% endfor %}
{% endblock %}

Answer 1

overriding the get_object(self, queryset=None) method instead of DetailView get_queryset(self) is an easier solution
class ArticleDetail(DetailView):
model = Detail
template_name = "article_detail.html"
context_object_name = "details"
def get_object(self, queryset=None):
slug = self.kwargs['slug']
a_obj = Article.objects.get(slug=slug)
try:
d_obj = Detail.objects.get(article=a_obj)
except Detail.DoesNotExist:
d_obj = None
except Detail.MultipleObjectsReturned:
#select the apt object
return d_obj

Answer 2

Solution: you need to rename slug parameter in url to other name, or in your view set slug_url_kwarg some other value - not 'slug'
Explanation:
When you add to url, django tries to get object by slug and your model Detail has no slug field.
Link to django code: https://github.com/django/django/blob/master/django/views/generic/detail.py#L33
UPDATE
in SingleObjectMixin:
slug = self.kwargs.get(self.slug_url_kwarg, None)
...
elif slug is not None:
slug_field = self.get_slug_field()
queryset = queryset.filter(**{slug_field: slug})
so django gets slug from your url, tries to get slug field from Detail model and fails
Your view need to rewrite slug_url_kwarg attribute:
class ArticleDetail(DetailView):
model = Detail
template_name = "article_detail.html"
context_object_name = "details"
slug_url_kwarg = "not_slug" # this attribute
def get_queryset(self):
print self.kwargs['slug']
a = Article.objects.get(slug=self.kwargs['slug'])
# print Details.object.get()
# print Detail.objects.filter(article__slug=self.kwargs['slug']) fails with same error
return Detail.objects.filter(article=a)
but I think better way is to change to attribute in your url:
url(r'^(?P<id>\d+)/(?P<article_slug>[-\w\d]+)/$', ArticleDetail.as_view(), name='article_detail'),
and get article_slug from view kwargs