old_contents: # -*- coding: utf-8 -*-
  
  from flask import render_template, redirect, request, url_for, flash
  from flask.ext.login import login_user, logout_user, login_required, \
      current_user
  
  from . import auth
  from .forms import LoginForm, RegistrationForm
  from .. import db
  from ..models import User
  
  
  @auth.route('/login', methods=['GET', 'POST'])
  def login():
      form = LoginForm()
      if form.validate_on_submit():
          user = User.query.filter_by(email=form.email.data).first()
          if user is not None:
              login_user(user)
              return redirect(request.args.get('next') or url_for('main.index'))
          flash('Invalid username or password.')
      return render_template('login.html', form=form)
  
  
  @auth.route('/logout')
  # @login_required
  def logout():
      logout_user()
      flash('You have been logged out.')
      return redirect(url_for('main.index'))
  
  
  @auth.route('/register', methods=['GET', 'POST'])
  def register():
      form = RegistrationForm()
      if form.validate_on_submit():
          user = User(email=form.email.data,
                      username=form.username.data,
                      password=form.password.data)
          db.session.add(user)
          db.session.commit()
          flash('You successfully registered. Welcome!')
          return redirect(url_for('auth.login'))
      return render_template('register.html', form=form)
  
new_contents: # -*- coding: utf-8 -*-
  
  from flask import render_template, redirect, request, url_for, flash
  from flask.ext.login import login_user, logout_user, login_required, \
      current_user
  
  from . import auth
  from .forms import LoginForm, RegistrationForm
  from ..models import User
  
  
  @auth.route('/login', methods=['GET', 'POST'])
  def login():
      form = LoginForm()
      if form.validate_on_submit():
          user = User.query.filter_by(email=form.email.data).first()
          if user is not None:
              login_user(user)
              return redirect(request.args.get('next') or url_for('main.index'))
          flash('Invalid username or password.')
      return render_template('login.html', form=form)
  
  
  @auth.route('/logout')
  # @login_required
  def logout():
      logout_user()
      flash('You have been logged out.')
      return redirect(url_for('main.index'))
  
  
  @auth.route('/register', methods=['GET', 'POST'])
  def register():
      form = RegistrationForm()
      if form.validate_on_submit():
          user = User(email=form.email.data,
                      username=form.username.data,
                      password=form.password.data)
          user.save()
          flash('You successfully registered. Welcome!')
          return redirect(url_for('auth.login'))
      return render_template('register.html', form=form)
  
subject: Use newly added save on new users.