hello.py

import os
# from threading import Thread
from flask import Flask, render_template, session, redirect, url_for
from flask_bootstrap import Bootstrap
from flask_moment import Moment
from flask_wtf import FlaskForm
from wtforms import StringField, SubmitField
from wtforms.validators import DataRequired
from flask_sqlalchemy import SQLAlchemy
from flask_migrate import Migrate
from flask_mail import Mail, Message

basedir = os.path.abspath(os.path.dirname(__file__)).replace("\\", "/")

app = Flask(__name__)
app.config['SECRET_KEY'] = 'hard to guess string'

# Unix SQLite configuration:
# app.config['SQLALCHEMY_DATABASE_URI'] =\
#    'sqlite:////' + os.path.join(basedir, 'data.sqlite')

# Windows SQLite configuration:
app.config['SQLALCHEMY_DATABASE_URI'] =\
    'sqlite:///' + basedir + '/data.sqlite'

app.config['SQLALCHEMY_COMMIT_ON_TEARDOWN'] = True
app.config['SQLALCHEMY_TRACK_MODIFICATIONS'] = False

# Gmail configuration:
# must run first in cmd/terminal OR edit the configurations for the PyCharm project to include these environment
# variables:
# > set FLASK_APP=hello
# > set MAIL_USERNAME=<Gmail username> (before the @gmail.com)
# > set MAIL_PASSWORD=<Gmail password>
# > set FLASKY_ADMIN=<Gmail username>
# Sometimes, you'll need to setup an "App Password" for GMail: https://myaccount.google.com/apppasswords
app.config['MAIL_SERVER'] = 'smtp.googlemail.com'
app.config['MAIL_PORT'] = 587
app.config['MAIL_USE_TLS'] = True
app.config['MAIL_USERNAME'] = os.environ.get('MAIL_USERNAME')
app.config['MAIL_PASSWORD'] = os.environ.get('MAIL_PASSWORD')
app.config['FLASKY_MAIL_SUBJECT_PREFIX'] = '[Flasky]'
app.config['FLASKY_MAIL_SENDER'] = 'Flasky Admin <flasky@example.com>'
app.config['FLASKY_ADMIN'] = os.environ.get('FLASKY_ADMIN')

bootstrap = Bootstrap(app)
moment = Moment(app)
db = SQLAlchemy(app)
migrate = Migrate(app, db)
mail = Mail(app)


class Role(db.Model):
    __tablename__ = 'roles'
    id = db.Column(db.Integer, primary_key=True)
    name = db.Column(db.String(64), unique=True)
    users = db.relationship('User', backref='role', lazy='dynamic')

    def __repr__(self):
        return '<Role %r>' % self.name


class User(db.Model):
    __tablename__ = 'users'
    id = db.Column(db.Integer, primary_key=True)
    username = db.Column(db.String(64), unique=True, index=True)
    role_id = db.Column(db.Integer, db.ForeignKey('roles.id'))

    def __repr__(self):
        return '<User %r>' % self.username


class NameForm(FlaskForm):
    name = StringField('What is your name?', validators=[DataRequired()])
    submit = SubmitField('Submit')


def send_async_email(appl, msg):
    with appl.app_context():
        mail.send(msg)


def send_email(to, subject, template, **kwargs):
    msg = Message(app.config['FLASKY_MAIL_SUBJECT_PREFIX'] + ' ' + subject,
                  sender=app.config['FLASKY_MAIL_SENDER'], recipients=[to])
    msg.body = render_template(template + '.txt', **kwargs)
    msg.html = render_template(template + '.html', **kwargs)
    mail.send(msg)
    # thr = Thread(target=send_async_email, args=[app, msg])
    # thr.start()
    # return thr


@app.errorhandler(404)
def page_not_found(e):
    return render_template('404.html'), 404


@app.errorhandler(500)
def internal_server_error(e):
    return render_template('500.html'), 500


@app.route('/', methods=['GET', 'POST'])
def index():
    form = NameForm()
    if form.validate_on_submit():
        user = User.query.filter_by(username=form.name.data).first()
        if user is None:
            user = User(username=form.name.data)
            db.session.add(user)
            db.session.commit()
            session['known'] = False
            if app.config['FLASKY_ADMIN']:
                send_email(app.config['FLASKY_ADMIN'], 'New User',
                           'mail/new_user', user=user)
        else:
            session['known'] = True
        session['name'] = form.name.data
        return redirect(url_for('index'))
    return render_template('index.html', form=form, name=session.get('name'),
                           known=session.get('known', False))