calendar-social/app/forms.py

from flask_babel import lazy_gettext as _
from flask_wtf import FlaskForm
from wtforms import PasswordField, StringField, BooleanField
from wtforms.ext.dateutil.fields import DateTimeField
from wtforms.validators import DataRequired, Email, ValidationError
from wtforms.widgets import TextArea


class RegistrationForm(FlaskForm):
    username = StringField(_('Username'), validators=[DataRequired()])
    email = StringField(_('Email address'), validators=[Email()])
    password = PasswordField(_('Password'), validators=[DataRequired()])
    password_retype = PasswordField(_('Password, once more'), validators=[DataRequired()])

    def validate_password_retype(self, field):
        if field.data != self.password.data:
            raise ValidationError(_('The two passwords must match!'))


class EventForm(FlaskForm):
    title = StringField(_('Title'), validators=[DataRequired()])
    time_zone = StringField(_('Time zone'), validators=[DataRequired()])
    start_time = DateTimeField(_('Start time'), validators=[DataRequired()])
    end_time = DateTimeField(_('End time'), validators=[DataRequired()])
    all_day = BooleanField(_('All day'))
    description = StringField(_('Description'), widget=TextArea())

    def validate_end_time(self, field):
        if field.data < self.start_time.data:
            raise ValidationError(_('End time must be later than start time!'))