How can I create custom fields in WTForms for Django?

How can I create custom fields in WTForms for Django?

To create custom fields in WTForms for Django, you can subclass the existing fields and implement your own validation and rendering logic.

Can you give me an example of a custom field?

Sure! Here's a simple example of a custom field that validates a phone number:

from wtforms import StringField
from wtforms.validators import ValidationError

class PhoneNumberField(StringField):
    def __init__(self, label=None, validators=None, **kwargs):
        super().__init__(label, validators, **kwargs)

    def pre_validate(self, form):
        if not self.data.isdigit():
            raise ValidationError('Invalid phone number!')

How do I use this custom field in a form?

You can use the custom field in your form like this:

from flask_wtf import FlaskForm

class MyForm(FlaskForm):
    phone = PhoneNumberField('Phone Number')

What if I want to add more validation rules?

You can add more validation rules by defining additional methods in your custom field class or by using WTForms validators.