如何在 Django 中创建与单个博客样式帖子相关的评论创建页面

Question

I am trying to create a comment creation page related to a single post on a blog-style site using Django.

The home page has a list of posts, each with a "comment" button. Ideally this "comment" button would then take you to a page that would have the original post listed at the top with the comment creation form underneath it.

I've been trying to figure out a way to access the data I'm looking for using primary keys but am not sure how to tie everything together.

Here are the 2 models I am trying to access ( Post and Comment ):

class Post(models.Model):
    user = models.ForeignKey(User, on_delete=models.CASCADE, null=True)
    title = models.CharField(max_length=128)
    content = models.TextField()
    image = models.ImageField(upload_to='post_pics', blank=True)
    date_posted = models.DateTimeField(default=timezone.now)

    def get_absolute_url(self):
        return reverse('home')

class Comment(models.Model):
    post = models.ForeignKey(Post, on_delete=models.CASCADE, related_name='comments')
    user = models.ForeignKey(User, on_delete=models.CASCADE)
    comment = models.TextField()
    date_created = models.DateTimeField(default=timezone.now)

And the urls.py :

from django.urls import path
from .views import PostCreateView, PostListView, VehicleListView, CommentCreateView
from . import views

urlpatterns = [
    path('', PostListView.as_view(), name='home'),
    path('comment/new/<int:pk>', CommentCreateView.as_view(), name='comment-create'),
]

This is my current HTML for the home page (currently adds the post id to the end of the HTML on linked "comment-create" page):

{% for post in posts %}
    <div class="infinite-item">
      <div class="card m-3">
        <div class="card-body" style="background-color:#bdcade; padding-bottom:0px">
          <div class="media mb-3">
            <img src="{{ user.profile.image.url }}" class="d-block ui-w-40 rounded-circle" style="width:40px;height:auto;" alt="">
            <div class="media-body ml-3">
              <h5 style="color:#ffffff">{{ post.user.username }}</h5>
              <div class="small text-muted">Yesterday</div>
            </div>
          </div>
        </div>

        <div class="card-body">
          <h5 class="card-title">{{ post.title }}</h5>
          <p class="card-text">{{ post.content }}</p>
          <div class="btn-group" role="group">
            <button type="button" class="btn btn-secondary">Like</button>
            <a class="btn btn-secondary" href="{% url 'comment-create' post.id %}" role="button">Comment</a>

          </div>
        </div>
      </div>
    </div>

This is my current HTML for the comment-creation page:

{% block content %}

  <div class="card m-3">
    <div class="card-body" style="background-color:#bdcade; padding-bottom:0px">
      <div class="media mb-3">
        <img src="{{ post.user.profile.image.url }}" class="d-block ui-w-40 rounded-circle" style="width:40px;height:auto;" alt="">
        <div class="media-body ml-3">
          <h5 style="color:#ffffff">{{ post.user.username }}</h5>
          <div class="small text-muted">{{ post.title }}</div>
        </div>
      </div>
    </div>

    <div class="card-body">
      <h5 class="card-title">{{ post.title }}</h5>
      <p class="card-text">{{ post.content }}</p>
      <div class="btn-group" role="group">
        <button type="button" class="btn btn-secondary">Like</button>
        <button type="button" class="btn btn-secondary">Comment</button>
      </div>
    </div>
  </div>

  <br>
  <div class="container primary-segments">
    <form method="POST" enctype="multipart/form-data">
      {% csrf_token %}
      <fieldset>
        {{ form|crispy }}
      </fieldset>
      <div class="form-group">
        <button class="btn btn-outline-info" type="submit">Post Comment</button>
      </div>
    </form>
  </div>

{% endblock content %}

Here is the view for comment creation page (using get_context_data to access the Post model):

class CommentCreateView(LoginRequiredMixin, CreateView):
    model = Comment
    template_name = 'home/comment-form.html'
    fields = ['comment',]

    def get_context_data(self, **kwargs):
        context = super(CommentCreateView, self).get_context_data(**kwargs)
        pk = self.kwargs['pk']
        context['post'] = Post.objects.filter(id=pk)
        return context

    def form_valid(self, form):
        form.instance.user = self.request.user
        return super().form_valid(form)

Currently, I can't access any of the data for the post in the comment creation page. I think it has to do with how I'm trying to tie the pk to the post within the -get_context_data` function. The primary key for the desired post is showing up in the URL, just not sure how to get at the right data.

Any help would be much appreciated. Thank you!

Answer 1

So it looks to me like you're using pk wrong here.

The pk in this code segment here:

def get_context_data(self, **kwargs):
        context = super(CommentCreateView, self).get_context_data(**kwargs)
        pk = self.kwargs['pk']

is the pk of the comment , however you're trying to use it to lookup a Post with context['post'] = Post.objects.filter(id=pk) . Remember that pk stands for primary key and references the object that you declared as the model for your view. If you want the Post associated with that Comment you'll need to search for it using Comment.post since that's the declared foreign key inside your model.

Answer 2

After a lot of Googling/trial-and-error, I found a solution that got me what I was looking for.

Updated my View from THIS (note: I was trying to force a specific PK to test if it would filter to the correct data, but for some reason I still couldn't access anything):

class CommentCreateView(LoginRequiredMixin, CreateView):
    model = Comment
    template_name = 'home/comment-form.html'
    fields = ['comment',]

    def get_context_data(self, **kwargs):
        context = super(CommentCreateView, self).get_context_data(**kwargs)
        pk = 7
        context['post'] = Post.objects.filter(id=pk)
        return context

    def form_valid(self, form):
        form.instance.user = self.request.user
        return super().form_valid(form)

To THIS:

class CommentCreateView(LoginRequiredMixin, CreateView):
    model = Comment
    template_name = 'home/comment-form.html'
    fields = ['comment',]

    def get_context_data(self, **kwargs):
        context = super(CommentCreateView, self).get_context_data(**kwargs)
        context['post'] = Post.objects.get(pk=self.kwargs['pk'])
        return context

    def form_valid(self, form):
        form.instance.user = self.request.user
        return super().form_valid(form)

Have a basic, high-level understanding of what this is doing (grabbing the PK from the URL), but am not entirely sure why the original .filter() method wasn't working.

If anyone could provide some context as to what's going on behind the scenes here, I'd love to see it.

Thanks!