Django 2.0中自定义表单验证器未触发问题求助

Hey Richard, let's work through why your clean_postcode validation method isn't running—there are a couple of straightforward fixes needed:

1. Your view isn't triggering form validation #

Right now, your index view only creates an empty form instance. Django runs validation (including custom clean_* methods) only when you call form.is_valid(), which you're not doing. You need to handle POST submissions in your view to trigger this process.

2. Typos in your form's clean method #

There are two small errors in your clean_postcode function that break it even if validation was triggered:

• You used self.clean_data instead of the correct attribute name self.cleaned_data
• You tried to return data, a variable that wasn't defined (you should return the processed postcode instead)

Fixed Code Examples #

Corrected forms.py:

from django import forms
from django.utils.translation import gettext_lazy as _

class PostcodeForm(forms.Form):
    postcode = forms.CharField(required=True, widget=forms.TextInput(
        attrs={
            'placeholder': "enter a postcode",
        }
    ))
    
    def clean_postcode(self):
        # Fixed: Use cleaned_data instead of clean_data
        postcode = self.cleaned_data.get('postcode', '')
        print('clean_postcode', postcode)
        if postcode != 'something':
            raise forms.ValidationError(_("Please enter a valid postcode"), code='invalid')
        # Fixed: Return the processed postcode variable
        return postcode

Corrected views.py:

from django.shortcuts import render
from .forms import PostcodeForm

def index(request):
    if request.method == 'POST':
        # Initialize form with POST submission data
        form = PostcodeForm(request.POST)
        # This line triggers all validation, including clean_postcode
        if form.is_valid():
            # Access validated data after successful check
            valid_postcode = form.cleaned_data['postcode']
            # Add your post-validation logic here (e.g., redirect, save data)
    else:
        # Empty form for GET requests
        form = PostcodeForm()
    
    context = {
        'form': form
    }
    return render(request, 'your_template_name.html', context)

Quick Template Check #

Make sure your template uses POST method and includes a CSRF token (required for Django form submissions):

<form method="POST">
    {% csrf_token %}
    {{ form.as_p }}
    <button type="submit">Submit</button>
</form>

With these changes, when a user submits the form, Django will run form.is_valid() and your clean_postcode method will execute as expected.

内容的提问来源于stack exchange，提问作者Richard