Flask-Login + Principal Basic

gistfile1.py

class LoginForm(Form):
    email = TextField('Email', validators=[Required()])
    password = PasswordField('Password', validators=[Required()])
    remember = BooleanField('Remember Me', default=True)


class UserRole(db.Model):
    __tablename__ = 'user_role'
    id = db.Column('user_role_id', db.Integer, primary_key=True)
    user_id = db.Column(db.Integer, db.ForeignKey('user.user_id'))
    role = db.Column(db.String)


class User(db.Model, UserMixin):
    __tablename__ = 'user'
    id = db.Column('user_id', db.Integer, primary_key=True)
    email = db.Column(db.String(155))
    password_hash = db.Column(db.String(40))    
    user_roles = db.relationship('UserRole', foreign_keys=[UserRole.user_id])


# decorator function for principal once an identity has been loaded we'll pull out the given user's roles
@identity_loaded.connect_via(app)
def on_identity_loaded(sender, identity):
    identity.user = current_user
    if hasattr(current_user, 'id'):
        identity.provides.add(UserNeed(current_user.id))

    if hasattr(current_user, 'user_roles'): # my user model contains a user_roles relationship
        for this_role in current_user.user_roles:
            identity.provides.add(RoleNeed(this_role.role.))

            
@app.route('/login', methods=['GET', 'POST'])
def login()
    form = LoginForm()
    if form.validate_on_submit():
        # authenticate user
        user = User.query.filter_by(email=request.form['email']).first()
        if user and user.check_password(request.form['password']) and user.id != 0:
            remember = request.form.get("remember", "no") == "yes"
            login_user(user, remember=remember)
            identity_changed.send(app, identity=Identity(user.id)) # call to principal
            return redirect(request.args.get("next") or url_for("router"))
        else:
            flash("Sorry, invalid username/password.", "danger") # I use flask-bootstrap so the category danger will create color coded messages
    return render_template('login.html', form=form, title="Account Log In",