doesNotExist at /blog/postComment 帖子匹配查询不存在

Question

我正在尝试打印博客下方的评论，但单击提交按钮后出现上述错误。我只想在网页顶部显示一条成功消息，为此我编写了以下行：messages.success(request, 'your comment has been added')，但出现错误！models.py:from django.db import modelsfrom django.contrib.auth.models import Userfrom django.utils.timezone import now# Create your models here.class Post(models.Model):    sno = models.AutoField(primary_key=True)    title = models.CharField(max_length=50)    content = models.TextField()    author = models.CharField(max_length=50)    slug = models.SlugField(max_length=200)    timeStamp = models.DateTimeField(blank=True)    def __str__(self):        return self.title + " by " + self.authorclass BlogComment(models.Model):    sno = models.AutoField(primary_key=True)    comment = models.TextField()    user = models.ForeignKey(User, on_delete=models.CASCADE)    post = models.ForeignKey(Post, on_delete=models.CASCADE)    parent = models.ForeignKey('self', on_delete=models.CASCADE, null=True)    timestamp = models.DateTimeField(default=now)urls.py:from django.urls import path, includefrom blog import viewsurlpatterns = [    path('postComment', views.postComment, name='postComment'),    path('', views.blogHome, name='home'),    path('<str:slug>', views.blogPost, name='blogpost'),]view.py:from django.shortcuts import render, HttpResponse, redirectfrom blog.models import Post, BlogCommentdef blogHome(request):    allpost = Post.objects.all()    context = {'allposts': allpost}    return render(request, 'blog/blogHome.html', context)def blogPost(request, slug):    post = Post.objects.filter(slug=slug).first()    comments = BlogComment.objects.filter(post=post)    context = {'post': post, 'comments': comments}    return render(request, 'blog/blogPost.html', context)

Answer 1

你的错误在模板中。name您的输入之一设置错误：

在你的代码中：

<input type="hidden" name = "comment" value = "{{post.sno}}">

正确版本：

<input type="hidden" name = "postSno" value = "{{post.sno}}">

Answer 2

将注释更改为注释，因为“注释”未定义。您正在使用评论。

Answer 3

为了解决您的第一个问题，您应该将该行post = Post.objects.get(sno=postSno)（在postComment函数中）更改为：

from django.http import Http404

try:

    post = Post.objects.get(sno=postSno)

except Post.DoesNotExist:

    return Http404("Post does not exist") # or return HttpResponse("Post does not exist")

因为在某些情况下该查询可能无法返回任何结果，因此会引发DoesNotExistError。第二个问题（我的意思是NameError at /blog/postComment name 'comments' is not defined）来自相同的函数...更改此行将comment = BlogComment(comment=comments, user=user, post=post)解决comment = BlogComment(comment=comment or '', user=user, post=post)此问题。