如何验证 Django 中的表单字段？

Question

我想确保 bid field 的当前值不小于当前最大值 bid。这是我使用自定义 clean 方法的表单。

表格：

class Place_A_Bid_Form(forms.Form):
    listing = forms.CharField(widget=forms.TextInput(attrs={"type":"hidden"}))
    bid = forms.IntegerField(widget=forms.NumberInput(attrs={"class":"form-control"}), min_value=1)

    def clean_bid(self, biggestBid):
        bid = self.cleaned_data["bid"]
        if bid < biggestBid:
            raise ValidationError("""New bid shouldn't be less than starting bid, or 
                                    if any bids have been placed then new bid 
                                    should be greater than current biggest bid""")
        return bid

查看：

def place_a_bid(request):
    if request.method == "POST":
        form = Place_A_Bid_Form(request.POST)
        user = User.objects.get(username=request.user.username)
        biggest_bid = Bid.objects.filter(user=user).aggregate(Max("amount"))
        if form.is_valid():
            data = form.cleaned_data
            user_obj = User.objects.get(username=request.user.username)
            listing_obj = Listing.objects.get(title=data["listing"])
            Bid.objects.update_or_create(
                user=user_obj,
                listing=listing_obj,
                amount=data["bid"]
            )
        return redirect(listing_obj)

鉴于我正在提取要与之比较的当前值，但我不知道如何将此值传递给我的表单字段的 clean 方法。或者也许我做错了？那么如何正确地进行这种验证呢？

Answer 1

class Place_A_Bid_Form(forms.Form):
    listing = forms.CharField(widget=forms.TextInput(attrs={"type":"hidden"}))
    bid = forms.IntegerField(widget=forms.NumberInput(attrs={"class":"form-control"}),
    min_value=1)

    def __init__(self,biggestBid=0 *args, **kwargs):
        super().__init__(*args, **kwargs)
        self.biggestBid = biggestBid

    def clean_bid(self):
        bid = self.cleaned_data["bid"]
        if bid < self.biggestBid:
            raise ValidationError("""New bid shouldn't be less than starting bid, or 
                                    if any bids have been placed then new bid 
                                    should be greater than current biggest bid""")
        return bid

然后在 views.py:

def place_a_bid(request):
    if request.method == "POST":
        dict = Bid.objects.filter(user=user).aggregate(Max("amount"))
        form = Place_A_Bid_Form(biggestBid=dict['amount__max'], data=request.POST)
        user = User.objects.get(username=request.user.username)
        if form.is_valid():
            data = form.cleaned_data
            user_obj = User.objects.get(username=request.user.username)
            listing_obj = Listing.objects.get(title=data["listing"])
            Bid.objects.update_or_create(
                user=user_obj,
                listing=listing_obj,
                amount=data["bid"]
            )
        return redirect(listing_obj)

Answer 2

Django 的 IntegerField [Django-doc] 可以在没有任何额外逻辑的情况下验证最小值，您可以设置 .min_value 并添加一个验证器：

from django.core.validators import MinValueValidator

class Place_A_Bid_Form(forms.Form):
    listing = forms.CharField(widget=forms.TextInput(attrs={'type': 'hidden'}))
    bid = forms.IntegerField(widget=forms.NumberInput(attrs={'class':'form-control'}))

    def __init__(self, *args, **kwargs, min_bid=0):
        super().__init__(*args, **kwargs)
        bid = self.fields['bid']
        min_bid += 1
        bid<strong>.min_value = min_bid</strong>
        bid<strong>.validators.add(MinValidator(min_bid))</strong>

那么你只需要将 min_bid 传递给表单：

from django.contrib.auth.decorators import login_required

@login_required
def place_a_bid(request):
    biggest_bid = Bid.objects.filter(user=request.user).aggregate(
        min_bid=Max('amount')
    )['min_bid'] or 0
    if request.method == 'POST':
        form = Place_A_Bid_Form(request.POST<strong>, min_bid=biggest_bid</strong>)
        if form.is_valid():
            data = form.cleaned_data
            listing_obj = Listing.objects.get(title=data['listing'])
            Bid.objects.update_or_create(
                user=request.user,
                listing=listing_obj,
                amount=data['bid']
            )
            return redirect(listing_obj)
    else:
        form = Place_A_Bid_Form(<strong>min_bid=biggest_bid</strong>)
    return render(request, '<em>app_name</em>/name-of-template.html', {'form': form})

在 GET 请求的情况下，这也构建了一个表单，将最大出价作为最低出价。这还将在 HTML 中将其添加为 min="<em>biggest-bid</em>" 以便浏览器可以验证这一点。因此，这也可以在提交表单之前在客户端验证出价，但也会在服务器端正确验证表单。

然而，最好不要通过表单传递列表，而是作为 URL 参数。

Note: You can limit views to a view to authenticated users with the @login_required decorator [Django-doc].

如何验证 Django 中的表单字段？

How to validate form field in django?

django

django-forms

django-validation