Django view in array - django

Question

I have 2 tables (posts, upvoted) that I am working within and am looking to see if a post has been upvoted already and if it has, replace the upvote arrow with a filled arrow. In my view, I am already sending over the Upvote object to my template and am trying to check if the post.id exists within the upvoted table. I tried the code below but it didn't work. How would I do it?
Model:
class Post(models.Model):
user = models.ForeignKey(User, related_name="posts", on_delete=models.DO_NOTHING)
body = models.CharField(max_length=255)
image = models.ImageField(
default="onebyone.png", upload_to="images/", blank=True, null=True
)
created_at = models.DateTimeField(auto_now_add=True)
post_karma = models.IntegerField(default=0, blank=True, null=True)
comment_count = models.IntegerField(default=0, blank=True, null=True)
def __str__(self):
return f"{self.user.username} - {self.created_at.strftime('%Y-%m-%d')} - {self.body[:30]}"
class Upvoted(models.Model):
user = models.ForeignKey(User, related_name="upvoted", on_delete=models.CASCADE)
post = models.ForeignKey(Post, related_name="upvoted", on_delete=models.CASCADE)
upvoted_at = models.DateTimeField(auto_now_add=True)
def __str__(self):
return (
f"{self.user.username} - {self.post.user.username} - {self.post.body[:30]}")
View:
#login_required
def dashboard(request):
# form = PostForm(request.POST or None)
# if request.method == "POST":
form = PostForm(request.POST, request.FILES)
if form.is_valid():
img = form.cleaned_data["image"]
body = form.cleaned_data["body"]
if img is None:
img = "images/onebyone.png"
post = Post.objects.create(user=request.user, image=img, body=body)
post.save()
return redirect("posty:dashboard")
sorting = request.GET.get("sort")
ordering = {
"date_sort": "-created_at",
"karma_sort": "-post_karma",
"comment_sort": "-comment_count",
None: "-created_at",
}
# followed_posts = Post.objects.filter(
# user__profile__in=request.user.profile.follows.all()
# ).order_by("-created_at")
followed_posts = Post.objects.filter(
user__profile__in=request.user.profile.follows.all()
).order_by(ordering[sorting])
# get current date_time
now = datetime.now()
return render(
request,
"posty/dashboard.html",
{"form": form, "posts": followed_posts, "comment": Comment, "now": now, "upvote" : Upvoted, "downvote" : Downvoted},)
{% if post.id in upvote.post_id.all %}

Answer 1

First, don't send your Model objects in context, you must do the queries in your view, then send the results to context.
Second:
You can use annotate() and Exists() for that.
from django.db.models import Exists, OuterRef
followed_posts = (
Post.objects.filter(
user__profile__in=request.user.profile.follows.all()
)
.annotate(
is_liked_by_user=Exists(
Upvoted.objects.filter(post_id=OuterRef('pk'), user=request.user)
)
)
.order_by(ordering[sorting])
)
Then in your template:
{% if post.is_liked_by_user %}
... put whatever you want here.
{% endif %}