python - Django表单错误: expected string or bytes-like object for datetime object?

Question

我有一个非常简单的 django 表单，用于出租 key ，该表单默认用户的到期日期，用户可以更改日期，然后继续保存表单。然而，每当我保存key_instance时，django都会抛出错误:预期字符串或类似字节的对象。我知道日期时间对象导致了这个错误，因为如果我将其注释掉，一切都会正常。这是我的views.py和forms.py

表单.py:

class UpdateKeyRequestForm(forms.Form):

    APPROVE_CHOICES = [
        ('d', 'Deny this key request'),
        ('a', 'Approve this key request')

    ]

    request_status = forms.CharField(label='Please select to accept or deny this request.',widget=forms.Select(choices=APPROVE_CHOICES))

    due_date = forms.DateField(help_text='Enter a date (YYYY-MM-DD) between now and 4 weeks (default 3). ')

    def clean_due_date(self):
        due_date = self.cleaned_data['due_date']
        approved_status = self.cleaned_data['request_status']

        # Check date is not in past.
        if due_date < datetime.date.today():
            raise ValidationError(_('Invalid date - renewal in past'))
        if due_date > datetime.date.today() + datetime.timedelta(weeks=4):
            raise ValidationError(_('Invalid date - renewal more than 4 weeks ahead'))


        return due_date, approved_status

views.py:

@permission_required('catalog.can_mark_returned')
def update_key_request(request, pk):
    """
    View function for renewing a specific keyInstance by admin
    """
    key_inst=get_object_or_404(KeyInstance, pk=pk)


    # If this is a POST request then process the Form data
    if request.method == 'POST':

        # Create a form instance and populate it with data from the request (binding):
        form = UpdateKeyRequestForm(request.POST)

        # Check if the form is valid:
        if form.is_valid():
            # process the data in form.cleaned_data as required (here we just write it to the model due_back field)
            request_status = form.cleaned_data['request_status']
            due_date = form.cleaned_data['due_date']
            if request_status == 'a':
                key_inst.due_back = due_date
                key_inst.status = 'o'
                key_inst.date_out = datetime.date.today()
                key_inst.save()
            else:
                key_inst.status = 'a'
                key_inst.save()

            # redirect to a new URL:
            return HttpResponseRedirect(reverse('all-available-keys'))
    else:
        default_due_date = datetime.date.today() + datetime.timedelta(weeks=3)
        form = UpdateKeyRequestForm(initial={'due_date': default_due_date})

    #If this is a GET (or any other method) create the default form.

    return render(request, 'catalog/roomkey_request_update.html', {'form': form, 'keyinst': key_inst})

但问题是我用完全相同的方法实现了这个精确的逻辑来更新截止日期，并且它仍然工作正常。我很困惑为什么这个会抛出错误。谁能解释一下吗？

这是错误页面上我的本地变量:

due_date    
(datetime.date(2018, 6, 13),)
form    
<UpdateKeyRequestForm bound=True, valid=True, fields=(due_date)>
key_inst    
<KeyInstance: Conestogo River (3fc9458a-5ec8-46a3-a04e-6a48e650b15f)>
pk  
UUID('3fc9458a-5ec8-46a3-a04e-6a48e650b15f')
request 
<WSGIRequest: POST '/catalog/key/3fc9458a-5ec8-46a3-a04e-6a48e650b15f/update'>

Answer 1

您的clean_due_date方法应该只返回 due_date .

def clean_due_date(self):
    ...
    return due_date

您似乎没有使用approved_status在该方法中，所以我将从该方法中删除这一行

approved_status = self.cleaned_data['request_status']

如果您确实需要 clean fields that rely on each other ，那么您应该在 clean() 中执行此操作方法而不是 clean_<fieldname>方法。