I am currently building a Python application, which let me use:
- Flask - a simple and very well documented web Framework
- Flask-Security - an extension
dedicated to user management.
While it is a really great extension, there is some documentation missing or quite hard to find on search engines or StackOverflow.
How to add fields to a Flask’s security form, with a custom validator.
First, we need to declare a new class, which extends RegisterForm, then add the
new fields we want on the form. If we want a custom validator for that field, we
need to define it, but, to avoid losing Flask-Security validator, just call it
Form.validate(self) The last thing needed is to tell Flask-Security to
use our form when instantiating it.
security = Security(app, user_datastore, register_form=ExtendedRegisterForm)
from flask.ext.wtf import Form from wtforms import StringField, BooleanField from wtforms.validators import DataRequired from flask_security.forms import RegisterForm from .models import User class ExtendedRegisterForm(RegisterForm): """ Add nickname field to the register's class """ nickname = StringField('Nickname', [DataRequired()]) def validate(self): """ Add nickname validation :return: True is the form is valid """ # Use standard validator validation = Form.validate(self) if not validation: return False # Check if nickname already exists user = User.query.filter_by( nickname=self.nickname.data).first() if user is not None: # Text displayed to the user self.nickname.errors.append('Nickname already exists') return False return True
And you are done !