How can I make an extra field required in flask-admin?

Question

I know using form_extra_fields can add an extra field in flask-admin. But how can I make it 'required'? Thanks in advance.

form_extra_fields = {
    'password2': PasswordField('Password')
}

Answer 1

Thanks a lot, Mech. Actually I figured out a simpler way:

from wtforms import validators
form_extra_fields = {
    'password2': PasswordField('password',[validators.DataRequired()])
}

Answer 2

You can use WTForms. See example below, pulled from Flask's documentation:

from wtforms import Form, BooleanField, TextField, PasswordField, validators

class RegistrationForm(Form):
    username = TextField('Username', [validators.Length(min=4, max=25)])
    email = TextField('Email Address', [validators.Length(min=6, max=35)])
    password = PasswordField('New Password', [
        validators.Required(),
        validators.EqualTo('confirm', message='Passwords must match')
    ])
    confirm = PasswordField('Repeat Password')
    accept_tos = BooleanField('I accept the TOS', [validators.Required()])

See the link for the other snippets (view, template, etc).