Chapter 5: User Logins (v0.5)

app/__init__.py

@@ -1,11 +1,14 @@
 from flask import Flask
 from flask_sqlalchemy import SQLAlchemy
 from flask_migrate import Migrate
+from flask_login import LoginManager
 from config import Config
 
 app = Flask(__name__)
 app.config.from_object(Config)
 db = SQLAlchemy(app)
 migrate = Migrate(app, db)
+login = LoginManager(app)
+login.login_view = 'login'
 
 from app import routes, models

app/forms.py

@@ -1,6 +1,7 @@
 from flask_wtf import FlaskForm
 from wtforms import StringField, PasswordField, BooleanField, SubmitField
-from wtforms.validators import DataRequired
+from wtforms.validators import ValidationError, DataRequired, Email, EqualTo
+from app.models import User
 
 
 class LoginForm(FlaskForm):
@@ -8,3 +9,22 @@ class LoginForm(FlaskForm):
     password = PasswordField('Password', validators=[DataRequired()])
     remember_me = BooleanField('Remember Me')
     submit = SubmitField('Sign In')
+
+
+class RegistrationForm(FlaskForm):
+    username = StringField('Username', validators=[DataRequired()])
+    email = StringField('Email', validators=[DataRequired(), Email()])
+    password = PasswordField('Password', validators=[DataRequired()])
+    password2 = PasswordField(
+        'Repeat Password', validators=[DataRequired(), EqualTo('password')])
+    submit = SubmitField('Register')
+
+    def validate_username(self, username):
+        user = User.query.filter_by(username=username.data).first()
+        if user is not None:
+            raise ValidationError('Please use a different username.')
+
+    def validate_email(self, email):
+        user = User.query.filter_by(email=email.data).first()
+        if user is not None:
+            raise ValidationError('Please use a different email address.')

app/models.py

@@ -1,8 +1,10 @@
 from datetime import datetime
-from app import db
+from app import db, login
+from flask_login import UserMixin
+from werkzeug.security import generate_password_hash, check_password_hash
 
 
-class User(db.Model):
+class User(UserMixin, db.Model):
     id = db.Column(db.Integer, primary_key=True)
     username = db.Column(db.String(64), index=True, unique=True)
     email = db.Column(db.String(120), index=True, unique=True)
@@ -12,6 +14,17 @@ class User(db.Model):
     def __repr__(self):
         return '<User {}>'.format(self.username)
 
+    def set_password(self, password):
+        self.password_hash = generate_password_hash(password)
+
+    def check_password(self, password):
+        return check_password_hash(self.password_hash, password)
+
+
+@login.user_loader
+def load_user(id):
+    return User.query.get(int(id))
+
 
 class Post(db.Model):
     id = db.Column(db.Integer, primary_key=True)

app/routes.py

@@ -1,12 +1,15 @@
-from flask import render_template, flash, redirect, url_for
-from app import app
-from app.forms import LoginForm
+from flask import render_template, flash, redirect, url_for, request
+from flask_login import login_user, logout_user, current_user, login_required
+from werkzeug.urls import url_parse
+from app import app, db
+from app.forms import LoginForm, RegistrationForm
+from app.models import User
 
 
 @app.route('/')
 @app.route('/index')
+@login_required
 def index():
-    user = {'username': 'Miguel'}
     posts = [
         {
             'author': {'username': 'John'},
@@ -17,14 +20,43 @@ def index():
             'body': 'The Avengers movie was so cool!'
         }
     ]
-    return render_template('index.html', title='Home', user=user, posts=posts)
+    return render_template('index.html', title='Home', posts=posts)
 
 
 @app.route('/login', methods=['GET', 'POST'])
 def login():
+    if current_user.is_authenticated:
+        return redirect(url_for('index'))
     form = LoginForm()
     if form.validate_on_submit():
-        flash('Login requested for user {}, remember_me={}'.format(
-            form.username.data, form.remember_me.data))
+        user = User.query.filter_by(username=form.username.data).first()
+        if user is None or not user.check_password(form.password.data):
+            flash('Invalid username or password')
+            return redirect(url_for('login'))
+        login_user(user, remember=form.remember_me.data)
+        next_page = request.args.get('next')
+        if not next_page or url_parse(next_page).netloc != '':
+            next_page = url_for('index')
+        return redirect(next_page)
+    return render_template('login.html', title='Sign In', form=form)
+
+
+@app.route('/logout')
+def logout():
+    logout_user()
+    return redirect(url_for('index'))
+
+
+@app.route('/register', methods=['GET', 'POST'])
+def register():
+    if current_user.is_authenticated:
         return redirect(url_for('index'))
-    return render_template('login.html',  title='Sign In', form=form)
+    form = RegistrationForm()
+    if form.validate_on_submit():
+        user = User(username=form.username.data, email=form.email.data)
+        user.set_password(form.password.data)
+        db.session.add(user)
+        db.session.commit()
+        flash('Congratulations, you are now a registered user!')
+        return redirect(url_for('login'))
+    return render_template('register.html', title='Register', form=form)

app/templates/base.html

@@ -10,7 +10,11 @@
         <div>
             Microblog:
             <a href="{{ url_for('index') }}">Home</a>
+            {% if current_user.is_anonymous %}
             <a href="{{ url_for('login') }}">Login</a>
+            {% else %}
+            <a href="{{ url_for('logout') }}">Logout</a>
+            {% endif %}
         </div>
         <hr>
         {% with messages = get_flashed_messages() %}

app/templates/index.html

@@ -1,7 +1,7 @@
 {% extends "base.html" %}
 
 {% block content %}
-    <h1>Hi, {{ user.username }}!</h1>
+    <h1>Hi, {{ current_user.username }}!</h1>
     {% for post in posts %}
     <div><p>{{ post.author.username }} says: <b>{{ post.body }}</b></p></div>
     {% endfor %}

app/templates/login.html

@@ -21,4 +21,5 @@
         <p>{{ form.remember_me() }} {{ form.remember_me.label }}</p>
         <p>{{ form.submit() }}</p>
     </form>
+    <p>New User? <a href="{{ url_for('register') }}">Click to Register!</a></p>
 {% endblock %}

app/templates/register.html

@@ -0,0 +1,37 @@
+{% extends "base.html" %}
+
+{% block content %}
+    <h1>Register</h1>
+    <form action="" method="post">
+        {{ form.hidden_tag() }}
+        <p>
+            {{ form.username.label }}<br>
+            {{ form.username(size=32) }}<br>
+            {% for error in form.username.errors %}
+            <span style="color: red;">[{{ error }}]</span>
+            {% endfor %}
+        </p>
+        <p>
+            {{ form.email.label }}<br>
+            {{ form.email(size=64) }}<br>
+            {% for error in form.email.errors %}
+            <span style="color: red;">[{{ error }}]</span>
+            {% endfor %}
+        </p>
+        <p>
+            {{ form.password.label }}<br>
+            {{ form.password(size=32) }}<br>
+            {% for error in form.password.errors %}
+            <span style="color: red;">[{{ error }}]</span>
+            {% endfor %}
+        </p>
+        <p>
+            {{ form.password2.label }}<br>
+            {{ form.password2(size=32) }}<br>
+            {% for error in form.password2.errors %}
+            <span style="color: red;">[{{ error }}]</span>
+            {% endfor %}
+        </p>
+        <p>{{ form.submit() }}</p>
+    </form>
+{% endblock %}