Chapter 5: Database use in the application (5b)

hello.py

@@ -1,5 +1,5 @@
 import os
-from flask import Flask, render_template, session, redirect, url_for, flash
+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
@@ -24,7 +24,7 @@ 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')
+ users = db.relationship('User', backref='role', lazy='dynamic')
 
  def __repr__(self):
  return '<Role %r>' % self.name
@@ -59,9 +59,15 @@ def internal_server_error(e):
 def index():
  form = NameForm()
  if form.validate_on_submit():
- old_name = session.get('name')
- if old_name is not None and old_name != form.name.data:
- flash('Looks like you have changed your name!')
+ 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
+ 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'))
+ return render_template('index.html', form=form, name=session.get('name'),
+ known=session.get('known', False))

templates/index.html

@@ -6,6 +6,11 @@
 {% block page_content %}
 <div class="page-header">
  <h1>Hello, {% if name %}{{ name }}{% else %}Stranger{% endif %}!</h1>
+ {% if not known %}
+ <p>Pleased to meet you!</p>
+ {% else %}
+ <p>Happy to see you again!</p>
+ {% endif %}
 </div>
 {{ wtf.quick_form(form) }}
 {% endblock %}