How do i make update function in Django - django

Question

My project is a discussion forum using Django and here are my create and update functions. The method of update_post should provide update functionality but every time I try to update a post it adds a new post. How can I update a resource?
#login_required
def create_post(request):
context = {}
form = PostForm(request.POST or None)
if request.method == "POST":
if form.is_valid():
print("\n\n its valid")
author = Author.objects.get(user=request.user)
new_post = form.save(commit=False)
new_post.user = author
new_post.save()
form.save_m2m()
return redirect("home")
context.update({
"form": form,
"title": "Create New Post"
})
return render(request, "create_post.html", context)
#login_required
def update_post(request):
context = {}
author = Author.objects.get(user=request.user)
form = PostForm(request.POST , instance=author)
if request.method == "POST":
if form.is_valid():
print("\n\n its valid")
new_post = form.save(commit=False)
# new_post.user = author
new_post.save()
form.save_m2m()
return redirect("home")
context.update({
"form": form,
"title": "UpdatePost",
})
return render(request, "update_post.html", context)
In model total there are 4 classes Post , comment , reply and category and this is Post -
class Post(models.Model):
title = models.CharField(max_length=400)
slug = models.SlugField(max_length=400, unique=True, blank=True)
user = models.ForeignKey(Author, on_delete=models.CASCADE)
content = HTMLField()
categories = models.ManyToManyField(Category)
date = models.DateTimeField(auto_now_add=True)
approved = models.BooleanField(default=True)
hit_count_generic = GenericRelation(HitCount, object_id_field='object_pk',
related_query_name='hit_count_generic_relation'
)
tags = TaggableManager()
comments = models.ManyToManyField(Comment, blank=True)
closed = models.BooleanField(default=False)
state = models.CharField(max_length=40, default="zero")
def save(self, *args, **kwargs):
if not self.slug:
self.slug = slugify(self.title)
super(Post, self).save(*args, **kwargs)
def __str__(self):
return self.title
def get_url(self):
return reverse("detail", kwargs={
"slug":self.slug
})
#property
def num_comments(self):
return self.comments.count()
#property
def last_reply(self):
return self.comments.latest("date")

Answer 1

form = PostForm(request.POST , instance=author)
instance feels like it should be passed an instance of Post instead of an instance of Author. I assume that PostForm is a pretty standard ModelForm with model = Post in the Meta.