Django错误'NoneType'对象没有属性'_meta'

时间:2019-07-04 06:23:28

标签: python django django-forms

我正在尝试构建一个社区页面,该页面既具有用于发布新帖子的形式,又具有所有先前帖子的列表,类似于facebook。但是现在我不断收到错误

'NoneType' object has no attribute '_meta'

这是我的查看功能:

def community(request):
    if redirect_if_false_choice(request):
        return redirect_if_false_choice(request)
    posts = CommunityPost.objects.filter(public=True).order_by('date_posted')
    form = PostForm(request.POST or None)
    if str(request.method) == 'GET':
       return render(request, 'officer/community.html', {'posts': posts, 'form': form})
    if form.is_valid():
       form.save()
       return redirect('community')

这是表格:

class PostForm(forms.ModelForm):
   class Meta:
        model = CommunityPost
        fields = ('content', )
        widgets = {
            'content': forms.Textarea(attrs={'rows': 4, 'placeholder': 
            "What's going on?"})
        }

整个堆栈跟踪:

Internal Server Error: /officer/community/
Traceback (most recent call last):
  File "/home/christian/PycharmProjects/django-securityofficerwanted/venv/lib/python3.6/site-packages/django/core/handlers/exception.py", line 34, in inner
    response = get_response(request)
  File "/home/christian/PycharmProjects/django-securityofficerwanted/venv/lib/python3.6/site-packages/django/core/handlers/base.py", line 115, in _get_response
    response = self.process_exception_by_middleware(e, request)
  File "/home/christian/PycharmProjects/django-securityofficerwanted/venv/lib/python3.6/site-packages/django/core/handlers/base.py", line 113, in _get_response
    response = wrapped_callback(request, *callback_args, **callback_kwargs)
  File "/home/christian/PycharmProjects/django-securityofficerwanted/security_officer_wanted/officer/views.py", line 114, in community
    return render(request, 'officer/community.html', {'posts': posts, 'form': form})
  File "/home/christian/PycharmProjects/django-securityofficerwanted/venv/lib/python3.6/site-packages/django/shortcuts.py", line 36, in render
    content = loader.render_to_string(template_name, context, request, using=using)
  File "/home/christian/PycharmProjects/django-securityofficerwanted/venv/lib/python3.6/site-packages/django/template/loader.py", line 62, in render_to_string
    return template.render(context, request)
  File "/home/christian/PycharmProjects/django-securityofficerwanted/venv/lib/python3.6/site-packages/django/template/backends/django.py", line 61, in render
    return self.template.render(context)
  File "/home/christian/PycharmProjects/django-securityofficerwanted/venv/lib/python3.6/site-packages/django/template/base.py", line 171, in render
    return self._render(context)
  File "/home/christian/PycharmProjects/django-securityofficerwanted/venv/lib/python3.6/site-packages/django/template/base.py", line 163, in _render
    return self.nodelist.render(context)
  File "/home/christian/PycharmProjects/django-securityofficerwanted/venv/lib/python3.6/site-packages/django/template/base.py", line 937, in render
    bit = node.render_annotated(context)
  File "/home/christian/PycharmProjects/django-securityofficerwanted/venv/lib/python3.6/site-packages/django/template/base.py", line 904, in render_annotated
    return self.render(context)
  File "/home/christian/PycharmProjects/django-securityofficerwanted/venv/lib/python3.6/site-packages/django/template/loader_tags.py", line 150, in render
    return compiled_parent._render(context)
  File "/home/christian/PycharmProjects/django-securityofficerwanted/venv/lib/python3.6/site-packages/django/template/base.py", line 163, in _render
    return self.nodelist.render(context)
  File "/home/christian/PycharmProjects/django-securityofficerwanted/venv/lib/python3.6/site-packages/django/template/base.py", line 937, in render
    bit = node.render_annotated(context)
  File "/home/christian/PycharmProjects/django-securityofficerwanted/venv/lib/python3.6/site-packages/django/template/base.py", line 904, in render_annotated
    return self.render(context)
  File "/home/christian/PycharmProjects/django-securityofficerwanted/venv/lib/python3.6/site-packages/django/template/loader_tags.py", line 62, in render
    result = block.nodelist.render(context)
  File "/home/christian/PycharmProjects/django-securityofficerwanted/venv/lib/python3.6/site-packages/django/template/base.py", line 937, in render
    bit = node.render_annotated(context)
  File "/home/christian/PycharmProjects/django-securityofficerwanted/venv/lib/python3.6/site-packages/django/template/base.py", line 904, in render_annotated
    return self.render(context)
  File "/home/christian/PycharmProjects/django-securityofficerwanted/venv/lib/python3.6/site-packages/django/template/defaulttags.py", line 209, in render
    nodelist.append(node.render_annotated(context))
  File "/home/christian/PycharmProjects/django-securityofficerwanted/venv/lib/python3.6/site-packages/django/template/base.py", line 904, in render_annotated
    return self.render(context)
  File "/home/christian/PycharmProjects/django-securityofficerwanted/venv/lib/python3.6/site-packages/django/template/library.py", line 192, in render
    output = self.func(*resolved_args, **resolved_kwargs)
  File "/home/christian/PycharmProjects/django-securityofficerwanted/venv/lib/python3.6/site-packages/image_cropping/templatetags/cropping.py", line 18, in cropped_thumbnail
    ratiofield = instance._meta.get_field(ratiofieldname)
AttributeError: 'NoneType' object has no attribute '_meta'
[04/Jul/2019 06:18:57] "GET /officer/community/ HTTP/1.1" 500 169040

2 个答案:

答案 0 :(得分:0)

从您提供的信息中无法确定。

毫无疑问,报告给您的错误提到了一个行号,该行号非常有用,看着它,您几乎可以肯定这是什么意思。产生错误的行可能在Django库中,但是您可以在任何明智的调试器中跟踪堆栈,直至代码在Django上调用并在那里抓头。

那是可能与您的经历有关的一个明显问题,即您上面的Meta类不是PostForm类的成员。参见:

https://docs.djangoproject.com/en/2.2/topics/forms/modelforms/

并尝试例如:

class PostForm(forms.ModelForm):
    class Meta:
        model = CommunityPost
        fields = ('content', )
        widgets = {
            'content': forms.Textarea(attrs={'rows': 4, 'placeholder': "What's going on?"})
        }

但是令我惊讶的是,这很可能是您在此处发布信息时出现的格式错误。非常不确定。我只能说,它看起来是错误的。

答案 1 :(得分:0)

我知道了,错误是该网站不知道是谁张贴了帖子,我已将其修复,现在可以正常工作了。 (模板在CommunityPost模型中调用了一个函数,该函数应返回发布该帖子的用户。但是由于没有人发布,因此它不返回任何帖子。)