django-forms：允許登錄用戶每個帖子只提交一條評論

Question

我有一個模型帖子，用戶可以在該帖子中留下評論以及一組評級。我想將用戶評論限制在每個帖子只有一個。我無法設置，在我的觀點

車型

class Comment(models.Model): 
    post = models.ForeignKey(Post, related_name="comments") 
    user = models.ForeignKey(User, related_name="usernamee") 
    ... 

class UserProfile(models.Model): 
    user = models.OneToOneField(User, related_name='profile') 

class Post(models.Model): 
... 

意見

def add_comment(request, slug): 
    post = get_object_or_404(Post, slug=slug) 

# I tried wrapping all of the below in an "if" statement, something like 
# if request.user.comment.exists(): to check if the user has already 
# left a comment on this specific post, but I'm not sure of the right way to perform such a check here. 

    if request.method == 'POST': 
      form = CommentForm(request.POST or None) 
      if form.is_valid(): 
       comment = form.save(commit=False) 
       comment.post = post 
       comment.user = request.user 
       comment.email = request.user.email 
       comment.picture = request.user.profile.profile_image_url() 

       comment.save() 

       messages.success(request, "Thank you for leaving a review!") 
       return redirect('blog:post_detail', slug=post.slug) 

      else: 
       messages.error(request, "Something went wrong! We weren't able to process your review :(") 
     else: 
      form = CommentForm() 



     template = "blog/post/add_comment.html" 
     context = { 

      'form': form, 
      'post': post, 
      #'comment_count': comment_count 

      } 
     return render(request, template, context) 

我的印象是，所有我需要是從包裹整個表單代碼在我add_comment視圖在某種驗證系統中檢查當前登錄用戶是否已經在該特定帖子上留言（請參閱評論）

任何人都知道可能的解決方案是什麼？或者，如果我甚至以正確的方式做這件事？

Answer 1

一個可能的解決方案可以是：

1. 獲取鑑於當前Post評論
2. 過濾的評論你的request.user
3. 查看該查詢返回非空查詢集

類似於：

from django.core.exceptions import PermissionDenied 


def add_comment(request, slug): 
    post = get_object_or_404(Post, slug=slug) 

    # Get the comments posted by the user for this post 
    user_comments = post.comments.filter(user=request.user) 

    if request.method == 'POST': 
      form = CommentForm(request.POST or None) 

      # Check if there are any comments posted by the user 
      if user_comments: 
       # If there are any, raise an error 
       raise PermissionDenied('You have already commented on this post.') 

      if form.is_valid(): 
       comment = form.save(commit=False) 
       comment.post = post 
       comment.user = request.user 
       comment.email = request.user.email 
       comment.picture = request.user.profile.profile_image_url() 

       comment.save() 

       messages.success(request, "Thank you for leaving a review!") 
       return redirect('blog:post_detail', slug=post.slug) 

      else: 
       messages.error(request, "Something went wrong! We weren't able to process your review :(") 
    else: 
     form = CommentForm() 

    template = "blog/post/add_comment.html" 
    context = { 
     'form': form, 
     'post': post 
    } 

    return render(request, template, context) 

當然，您可以修改此處引發的錯誤，但主要想法是通過request.user獲取註釋並過濾它們，並查看是否有任何錯誤。