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get_object_or_404 only for DetailView

Im new to programming, im working on a app to study a given topic, and after I read the topic, im showing some flashcards, but I want to show only the flashcards related to the topic, but I always get more then one Deck of flashcards, probably because I'm not getting the correct deck_id. Here is the code:
models.py:
class Topic(models.Model):
author = models.ForeignKey(
User, related_name="topic", on_delete=models.CASCADE, null=True)
title = models.CharField(max_length=100)
body = RichTextUploadingField(blank=True, null=True)
created_at = models.DateTimeField(auto_now_add=True)
slug = models.SlugField(max_length=120)
class Meta:
ordering = ["title"]
def __str__(self):
return self.title
def get_absolute_url(self):
return reverse('topic:topic-detail', kwargs={
"topic_slug": self.slug,})
class Deck(models.Model):
deckTopic = models.ForeignKey(
Topic, null=True, blank=True, on_delete=models.CASCADE)
description = models.CharField(max_length=510, null=False, blank=True)
is_active = models.BooleanField(default=False)
def __str__(self):
return self.description
def get_number_of_cards(self):
'''
Returns the number of cards in the decks related card_set
'''
return self.card_set.count()
get_number_of_cards.short_description = 'Card Count'
class Card(models.Model):
parentDeck = models.ForeignKey(Deck, on_delete=models.CASCADE)
front = models.TextField()
back = models.TextField()
def __str__(self):
return self.front
def has_prev_card(self):
'''
Returns true if card is not thee first card in the deck.
'''
first_card_in_deck = self.parentDeck.card_set.first()
if self == first_card_in_deck:
return False
return True
def get_prev_card(self):
'''
Return previous card in deck
'''
return self.parentDeck.card_set.filter(id__lt=self.id).last()
def has_next_card(self):
'''
Returns true if card is not the last card in the deck.
'''
last_card_in_deck = self.parentDeck.card_set.last()
if self == last_card_in_deck:
return False
return True
def get_next_card(self):
'''
Return next card in deck
'''
return self.parentDeck.card_set.filter(id__gt=self.id).first()
views:
class TopicDetailView(DetailView):
model = Topic
def get_context_data(self, *args, **kwargs):
context = super(TopicDetailView,
self).get_context_data(*args, **kwargs)
# Here is where i want to get the Deck related to the topic, but get more then one:
deck_obj = get_object_or_404(Deck)
card_list = deck_obj.card_set.all()
card_obj = card_list.first()
if self.request.method == 'GET' and 'card' in self.request.GET:
card_obj = get_object_or_404(Card, id=self.request.GET['card'])
context['deck_obj'] = deck_obj
context['card_obj'] = card_obj
return context
topic_detail.html:
{% extends 'base.html' %}
{% block content %}
<div class="topic-title">
<h5 class="mb-0">
{{object.title}}
</h5>
</div>
<div class="topic-body">
<p class="mb-0">
{{object.body}}
</p>
</div>
<div class="topic-deck">
{% if card_obj %}
<div class="notecard">
<div class="notecard-nav text-center">
{% if card_obj.has_prev_card %}
<a href="{% url 'topic:viewDeck' deck_obj.id %}?card=
{{card_obj.get_prev_card.id}}">Prev</a>
{% endif %}
{% if card_obj.has_next_card %}
<a href="{% url 'topic:viewDeck' deck_obj.id %}?card=
{{card_obj.get_next_card.id}}">Next</a>
{% endif %}
</div>
<div class="notecard-front">
<p class="text-center">Front</p>
<p>{{card_obj.front}}</p>
</div>
<div class="notecard-back">
<p class="text-center">Back</p>
<p>{{card_obj.back}}</p>
</div>
</div>
{% else %}
<p>No card found.</p>
{% endif %}
</div>
{% endblock %}
urls.py:
app_name = 'topic'
urlpatterns = [
path('topic/<slug:topic_slug>/<deck_id>/',
TopicDetailView.as_view(), name='viewDeck'),
]
How can I show only the Deck related to de Topic detail?

Your call to get_object_or_404 is incomplete. You've provided the model class, but not the parameters to get the object with:
deck_obj = get_object_or_404(Deck, pk=self.kwargs['deck_id'])
self.kwargs, contains all keyword arguments from the url. In your case it will contain topic_slug and deck_id.
pk is a shortcut for whatever the primary key is on your model. This makes me not think about how I named it and is resistant to future name changes of the primary key field.
I don't have to worry about deck_id not being in kwargs, because if it's not the URL won't match and the view isn't called.
And there it is :)

how to get unique values in django

I have a category model and list of posts related to those category also some post with same category name but when i wanted to make list of category section in template,
it showing duplicate name of category as it related to posts like:
food,
food,
desert,
style,
desert,
but I want like:
food,
desert,
style,
here is my code:
views.py
class ListCategory(ListView):
model = Post
paginate_by = 2
template_name = 'shit.html'
context_object_name = 'queryset'
def get_context_data(self, **kwargs):
context = super().get_context_data(**kwargs)
cate = Post.objects.all()
context['cate'] = cate
return context
models.py
class Category(models.Model):
title = models.CharField(max_length=20)
thumbnail = models.ImageField()
detail = models.TextField()
featured = models.BooleanField(default=True)
def __str__(self):
return self.title
def get_absolute_url(self):
return reverse('post-category', kwargs={
'pk': self.pk
})
class Post(models.Model):
title = models.CharField(max_length=100)
overview = models.TextField()
featured = models.BooleanField(default=True)
timestamp = models.DateTimeField(auto_now_add=True)
user = models.ForeignKey(Author,on_delete=models.CASCADE)
thumbnail = models.ImageField()
category = models.ForeignKey(Category, on_delete=models.CASCADE)
tags = TaggableManager()
def __str__(self):
return self.title
def get_absolute_url(self):
return reverse('post-detail', kwargs={
'pk': self.pk
})
templates
{% extends "base.html" %}
{% load static %}
{% block content %}
<div class="sidebar-box ftco-animate">
<ul class="categories">
<h3 class="heading mb-4">Categories</h3>
{% for cat in cate %}
<li>{{cat.category}}<span>(12)</span></li>
{% endfor %}
</ul>
</div>
{% endblock content %}
Thank you so much!

Seems like you want to group your Posts, based on their category; so you can achieve that by iterating over the Category (instead of Post), and use the backward relationship to find out the related Post objects.
views.py
class ListCategory(ListView):
model = Category
paginate_by = 2
template_name = 'shit.html' # :)
context_object_name = 'queryset'
template:
{% extends "base.html" %}
{% load static %}
{% block content %}
<div class="sidebar-box ftco-animate">
<ul class="categories">
<h3 class="heading mb-4">Categories</h3>
{% for category in queryset %}
<li>{{category}}<span>{{ category.posts_set.count }}</span></li>
<ul>
{% for post in category.post_set.all %}
<li>{{ post }}</li>
{% endfor %}
</ul>
{% endfor %}
</ul>
</div>
{% endblock content %}
I also use {{ category.post_set.count }} instead of 12, since I think you are looking for the number of Post objects within each category.

You can use unique=True in desired field, to make every value unique. If you'll try to add new record with same value of unique field, a django.db.IntegrityError will be raised.
More about unique
More about model's fields options

How to modify Django query_set before serving it in a ListView

I have a Django project with a database of Song Objects that users can search through.
My models.py looks like this:
class Songs(models.Model):
title = models.CharField(max_length=100)
artist = models.CharField(max_length=100)
link = models.CharField(max_length=255, unique=True)
album = models.CharField(max_length=100)
duration = models.CharField(max_length=40) # Duration in num_secs
and my views.py looks like this:
class ResultsView(ListView):
template_name = os.path.join(APPNAME, "results.html")
model = Songs
context_object_name = 'results'
paginate_by = 60
ordering = ['title']
def get_context_data(self, **kwargs):
context = super(ResultsView, self).get_context_data(**kwargs)
context['query'] = self.request.GET.get('query')
return context
def get_queryset(self, **kwargs):
query = self.request.GET.get('query')
query_set = Songs.objects.all()
results = query_set.filter(title__icontains=query)
return list(results)
And my results.html template looks like this:
{% if results %}
<div class="container-fluid">
<div class="row">
{% for result in results %}
<div class="col-md-2 result-col">
<a data-toggle="tooltip" title="{{ result.title }}" target="_blank" href="/song/{{ result.id }}">
<div class="result-text">{{ result.title }} </div>
<div class="result-dur">{{ result.duration }}</div>
</a>
</div>
{% endfor %}
</div>
</div>
{% else %}
<h2>No Results</h2>
{% endif %}
Due to the way the data is initially stored in my DB, the duration of each song is stored as the number of seconds, ie a song that is 2 minutes long is stored with a duration of 120. However, I want to display it on the template in the format: "hh:mm:ss".
How can I modify my ResultsView class so that I can parse the duration field of all of the objects in my query_set so that they have a more readable duration?
Note: to be 100% clear, I know how to do the actual conversion, using strftime. What I don't know, is how to access the Song.duration fields in my ResultsView.

You could add a method or property to your model:
#property
def converted_time(self):
return <your converted time>
And in your template {{ result.converted_time }}

You can just use a custom template tag.
Ref
snippet
#register.filter()
def formatSeconds(s):
mins = math.floor(s / 60);
secs = math.floor(s - (mins * 60));
return "%d:%02d" % (mins, secs);

Django: My template is not loading/being called

Edit: as #HåkenLid said, I should've asked this as 2 separate posts, the first question (regarding the template) has been answered!
I'm new to Django and I've been having a nice time with it so far. I'm trying to build a blog for fun but I've run with the some problems.
Here are my models, forms, urls, views and file tree:
http://i.imgur.com/KsLV3d9.png
For the first problem: (To save space I've only added parts of each file)
#blog/views.py
class BlogDetail(generic.DetailView):
model = Entry
template_name = "blog/entry_detail.html"
#blog/templates/blog/entry_detail.html
{% extends "base.html" %}
{% load django_markdown %}
<div class="post">
<h2>{{ object.title }}</h2>
<p class="meta">
{{ object.creation_date }} |
Tagged under {{ object.tags.all|join:", " }}
</p>
{{ object.body|markdown }}
</div>
#blog/urls.py
urlpatterns = patterns(
'',
url(r'^$', views.BlogIndex.as_view(), name="index"),
url(r'^entry/(?P<slug>\S+)$', views.BlogDetail.as_view(), name="entry_detail"),
)
#blog/models.py
class Entry(models.Model):
title = models.CharField(max_length=100)
body = models.TextField()
slug = models.SlugField(max_length=100, unique=True)
creation_date = models.DateTimeField(editable=False)
publication_date = models.DateTimeField(editable=False, null=True)
modification_date = models.DateTimeField(editable=False)
author = models.ForeignKey(User)
categories = models.ManyToManyField(Category)
tags = models.ManyToManyField(Tag)
objects = EntryQuerySet.as_manager()
def __str__(self):
return self.title
def was_published_recently(self):
now = datetime.datetime.now()
return now - datetime.timedelta(days=1) <= self.publication_date <= now
def is_published(self):
return self.publication_date is not False
is_published.boolean = True
is_published.short_description = 'Is it Published?'
def get_absolute_url(self):
return reverse("entry_detail", kwargs={"slug": self.slug})
class Meta():
verbose_name = "Blog Entry"
verbose_name_plural = "Blog Entries"
ordering = ['-creation_date']
def save(self, *args, **kwargs):
""" On save, update timestamps """
if not self.id:
self.creation_date = datetime.datetime.now()
self.modification_date = datetime.datetime.now()
return super(Entry, self).save(*args, **kwargs)
When I enter something like
localhost:8000/entry/this-is-an-entry-title-slug
e.j: http://i.imgur.com/c7yir79.png
I don't get the detail of the entry, just the title defined in base.html and that kind of stuff, I really don't know why it isn't being loaded.
As always, thank you very much for your help, and sorry if this are very basic questions but I haven't been able to find any solutions so far.

When extending templates you need to use {% block %}
If you have a block called 'content' in base.html, you can do this:
#blog/templates/blog/entry_detail.html
{% extends "base.html" %}
{% load django_markdown %}
{% block content %}
<div class="post">
<h2>{{ object.title }}</h2>
<p class="meta">
{{ object.creation_date }} |
Tagged under {{ object.tags.all|join:", " }}
</p>
{{ object.body|markdown }}
</div>
{% endblock content %}

For part 1, I think the issue is with your regex:
r'^entry/(?P<slug>\S+)$
Should be:
r'^entry/(?P<slug>[-\w\d]+)/'
Since your current pattern isn't capturing the slug, it's not being loaded into the context.
I am not much help on part 2, sorry. If you were doing this in your own view you could override the form_valid method of the CBV, but I am not sure how to accomplish the same within the built-in admin panel.

Calling a method from template

I seem to have a problem with calling a method from a django template. Given the model:
class Gallery(models.Model):
class Meta:
verbose_name_plural = "Galerie"
def photo_count(self):
return self.photo_set.count()
def random_image(self):
return self.photo_set.get(id=random.randint(1,self.photo_count()))
title = models.CharField(max_length=50)
imgur_id = models.CharField(max_length=15)
date_created = models.DateTimeField('Data utworzenia', auto_now=True)
is_active = models.BooleanField()
def __unicode__(self):
return self.title
where Gallery is foreignKey for Photo
views.py:
def index(request):
galleries = Gallery.objects.get(is_active=True)
if galleries.count() is 0:
messages.warning(request, "Niestety, żadna galeria nie jest aktywna, zaglądnij niebawem!")
return redirect(reverse(home))
elif galleries.count() is 1:
return render(request, 'gallery/home.html', {'gallery': galleries})
else:
return render(request, 'gallery/index.html', {'galleries': galleries})
I want to do this in template:
{% for gallery in galleries %}
{{ gallery.random_image }} <br />
{% endfor %}
The result I get is:
[ Photo object ]
[]
[]
[]
But when i call
{% for gallery in galleries %}
{{ gallery.photo_count }} <br />
{% endfor %}
The result is correct.
Why does this not work?

In my opinion you are complicated a little bit.
class Gallery(models.Model):
class Meta:
verbose_name_plural = "Galerie"
def random_image(self):
return self.photo_set.order_by('?')[0] if self.photo_set.count() else None
title = models.CharField(max_length=50)
imgur_id = models.CharField(max_length=15)
date_created = models.DateTimeField('Data utworzenia', auto_now=True)
is_active = models.BooleanField()
def __unicode__(self):
return self.title
and in the template,
{% for gallery in galleries %}
{% if gallery.random_image %}
{{ gallery.random_image }} <br />
{% else %}
No images found.
{% endif %}
{% endfor %}
Read more on order_by here
Note that ? could prove slightly heavy. If so, get thelist of ids of the photo_set associated with this gallery object, and get a random id from this list, rather than doing a
random.randint(1,self.photo_count())

Add #property to your fonction.
#property
def photo_count(self):
return self.photo_set.count()