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
@@ -25,7 +25,7 @@ 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
@@ -60,9 +60,16 @@ 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('Loks 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
+        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 %}