Django model relationships in views and templates - django

Question

I'm working on multi-user rss reader. I want to limit display of posts only to those which are unread. I've managed to do this in my single "feed" view as below, but I can't figure out how to do the same in multiple feed aka "category" view.
I've been trying something like here https://docs.djangoproject.com/en/1.5/topics/db/queries/#spanning-multi-valued-relationships but it didn't work for me
Should I change my "category" view code or template code? and if so how would you go about it?
thanks!
-S
models
class UserCategory(models.Model):
name = models.CharField(unique=False, max_length=64)
user = models.ForeignKey(User)
slug = AutoSlugField(populate_from='name', always_update='True', unique_with='user')
class Feed(models.Model):
feed_url = models.URLField(unique=True)
default_title = models.CharField(max_length=64, blank=True)
link = models.URLField(blank=True)
class UserFeed(models.Model):
feed = models.ForeignKey(Feed)
title = models.CharField(max_length=64)
category = models.ForeignKey(UserCategory)
user = models.ForeignKey(User)
slug = AutoSlugField(populate_from='title', always_update='True', unique_with='user')
class Post(models.Model):
feed = models.ForeignKey(Feed)
title = models.CharField(max_length=256)
content = models.TextField()
link = models.URLField(max_length=512)
class ReadPost(models.Model):
user = models.ForeignKey(User)
post = models.ForeignKey(Post)
views
def feed(request, user_feed_slug):
user_feed = get_object_or_404(UserFeed.objects.filter(slug=user_feed_slug, user=request.user))
read_post = ReadPost.objects.filter(user=request.user).values_list('post')
posts = Post.objects.select_related().filter(feed=user_feed.feed).exclude(id__in=read_post)
def category(request, user_category_slug):
user_category = get_object_or_404(UserCategory.objects.filter(slug=user_category_slug, user=request.user))
templates
feed
{% for post in posts %}
{{ post.title }}
{% endfor %}
category
{% for feed in user_category.userfeed_set.all %}
{{ feed.title }}
{% for post in feed.feed.post_set.all %}
{{ post.title }}
{{ post.content }}
{% endfor %}
{% endfor %}

Answer 1

You can write custom template filter, i.e:
#register.filter
def unread(posts, read_posts):
return posts.exclude(id__in=read_posts)
(before you must pass read_post to category template context).

Answer 2

Try this queryset:
def category(request, user_category_slug):
user_category = get_object_or_404(UserCategory, slug=user_category_slug,
user=request.user))
feeds = UserFeed.objects.filter(category__slug=user_category_slug, user=request.user)\
.prefetch_related('feed__post_set')
then in your template:
{% for feed in feeds %}
{{ feed.title }}
{% for post in feed.feed.post_set.all %}
{{ post.title }}
{{ post.content }}
{% endfor %}
{% endfor %}