I'm receiving user registration data from an iOS application and I'd like to use the validators that come with wtforms to make sure the email and password are acceptable. However, I'm not using a flask form since users are inputting the data from iOS textfields. Is it possible to check the incoming JSON data with the wtforms validators?

@auth.route('/register', methods=['POST'])
def register():try:user = User.register_fromJSON(request.json)email_success = validate_email(user)username_success = validate_username(user)if email_success == 1 and username_success == 1:db.session.add(user)db.session.commit()return jsonify({'Success': 1})else:return jsonify({'Failure': 0})except Exception:return jsonify({'Failure': 0})def validate_email(user):if User.query.filter_by(email=user.email).first() == None:return 1else:return 0def validate_username(user):if User.query.filter_by(username=user.username).first() == None:return 1else:return 0

EDIT

I created a Registration form:

class RegistrationForm(Form):email = StringField('Email', validators=[Required(), Length(1,64), Email()])username = StringField('Username', validators=[Required(), Length(1, 64), Regexp('^[A-Za-z][A-Za-z0-9_.]*$', 0, 'Usernames must have only letters, 'numbers, dots or underscores')])password = PasswordField('Password', validators=[Required()])def validate_email(self, field):if User.query.filter_by(email=field.data).first():print("Email already registered.")raise ValidationError('Email already registered.')def validate_username(self, field):if User.query.filter_by(username=field.data).first():print("Username already in use.")raise ValidationError('Username already in use.')

registration function has been updated to:

@auth.route('/register', methods=['POST'])
def register():try:data = MultiDict(mapping=request.json)form = RegistrationForm(data)if form.validate():user = User.register_fromJSON(request.json)db.session.add(user)db.session.commit()return jsonify({'Success': 1})else:return jsonify({'Success': 2})except Exception:return jsonify({'Success': 3})

Yes, this is entirely possible - the wtforms.Form constructor takes any MultiDict like interface (it just needs to have getlist), so you can just create an instance of werkzeug.datastructures.MultiDict from your JSON:

data = MultiDict(mapping=request.json)
form = YourForm(data)
if form.validate():# Data is correct

(assuming the field names match) and things will just work.