Chapter 8: Login and logout with Flask-Login (8c)

app/__init__.py

@@ -3,6 +3,7 @@ from flask_bootstrap import Bootstrap
 from flask_mail import Mail
 from flask_moment import Moment
 from flask_sqlalchemy import SQLAlchemy
+from flask_login import LoginManager
 from config import config
 
 
@@ -12,6 +13,10 @@ moment = Moment()
 db = SQLAlchemy()
 
 
+login_manager = LoginManager()
+login_manager.login_view = 'auth.login'
+
+
 def create_app(config_name):
     app = Flask(__name__)
     app.config.from_object(config[config_name])
@@ -21,6 +26,7 @@ def create_app(config_name):
     mail.init_app(app)
     moment.init_app(app)
     db.init_app(app)
+    login_manager.init_app(app)
 
     from .main import main as main_blueprint
     app.register_blueprint(main_blueprint)

app/auth/forms.py

@@ -0,0 +1,11 @@
+from flask_wtf import FlaskForm
+from wtforms import StringField, PasswordField, BooleanField, SubmitField
+from wtforms.validators import DataRequired, Length, Email
+
+
+class LoginForm(FlaskForm):
+    email = StringField('Email', validators=[DataRequired(), Length(1, 64),
+                                             Email()])
+    password = PasswordField('Password', validators=[DataRequired()])
+    remember_me = BooleanField('Keep me logged in')
+    submit = SubmitField('Log in')

app/auth/views.py

@@ -1,7 +1,28 @@
-from flask import render_template
+from flask import render_template, redirect, request, url_for, flash
+from flask_login import login_user, logout_user, login_required
 from . import auth
+from ..models import User
+from .forms import LoginForm
 
 
-@auth.route('/login')
+@auth.route('/login', methods=['GET', 'POST'])
 def login():
-    return render_template('auth/login.html')
+    form = LoginForm()
+    if form.validate_on_submit():
+        user = User.query.filter_by(email=form.email.data).first()
+        if user is not None and user.verify_password(form.password.data):
+            login_user(user, form.remember_me.data)
+            next = request.args.get('next')
+            if next is None or not next.startswith('/'):
+                next = url_for('main.index')
+            return redirect(next)
+        flash('Invalid username or password')
+    return render_template('auth/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'))

app/main/views.py

@@ -1,29 +1,7 @@
-from flask import render_template, session, redirect, url_for, current_app
-from .. import db
-from ..models import User
-from ..email import send_email
+from flask import render_template
 from . import main
-from .forms import NameForm
 
 
 @main.route('/', methods=['GET', 'POST'])
 def index():
-    form = NameForm()
-    if form.validate_on_submit():
-        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
-            if current_app.config['FLASKY_ADMIN']:
-                send_email(current_app.config['FLASKY_ADMIN'], 'New user',
-                           'mail/new_user', user=user)
-        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'),
-                           known=session.get('known', False))
+    return render_template('index.html')

app/models.py

@@ -1,5 +1,6 @@
 from werkzeug.security import generate_password_hash, check_password_hash
-from . import db
+from flask_login import UserMixin
+from . import db, login_manager
 
 
 class Role(db.Model):
@@ -12,9 +13,10 @@ class Role(db.Model):
         return '<Role %r>' % self.name
 
 
-class User(db.Model):
+class User(UserMixin, db.Model):
     __tablename__ = 'users'
     id = db.Column(db.Integer, primary_key=True)
+    email = db.Column(db.String(64), unique=True, index=True)
     username = db.Column(db.String(64), unique=True, index=True)
     role_id = db.Column(db.Integer, db.ForeignKey('roles.id'))
     password_hash = db.Column(db.String(128))
@@ -32,3 +34,8 @@ class User(db.Model):
 
     def __repr__(self):
         return '<User %r>' % self.username
+
+
+@login_manager.user_loader
+def load_user(user_id):
+    return User.query.get(int(user_id))

app/templates/auth/login.html

@@ -1,4 +1,5 @@
 {% extends "base.html" %}
+{% import "bootstrap/wtf.html" as wtf %}
 
 {% block title %}Flasky - Login{% endblock %}
 
@@ -6,4 +7,7 @@
 <div class="page-header">
     <h1>Login</h1>
 </div>
+<div class="col-md-4">
+    {{ wtf.quick_form(form) }}
+</div>
 {% endblock %}

app/templates/base.html

@@ -25,6 +25,13 @@
             <ul class="nav navbar-nav">
                 <li><a href="{{ url_for('main.index') }}">Home</a></li>
             </ul>
+            <ul class="nav navbar-nav navbar-right">
+                {% if current_user.is_authenticated %}
+                <li><a href="{{ url_for('auth.logout') }}">Log out</a></li>
+                {% else %}
+                <li><a href="{{ url_for('auth.login') }}">Log in</a></li>
+                {% endif %}
+            </ul>
         </div>
     </div>
 </div>

app/templates/index.html

@@ -1,16 +1,9 @@
 {% extends "base.html" %}
-{% import "bootstrap/wtf.html" as wtf %}
 
 {% block title %}Flasky{% endblock %}
 
 {% 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 %}
+    <h1>Hello, {% if current_user.is_authenticated %}{{ current_user.username }}{% else %}Stranger{% endif %}!</h1>
 </div>
-{{ wtf.quick_form(form) }}
 {% endblock %}

migrations/versions/655013143dbb_.py

@@ -0,0 +1,30 @@
+"""empty message
+
+Revision ID: 655013143dbb
+Revises: e7148b675688
+Create Date: 2018-11-01 23:41:21.492859
+
+"""
+from alembic import op
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision = '655013143dbb'
+down_revision = 'e7148b675688'
+branch_labels = None
+depends_on = None
+
+
+def upgrade():
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.add_column('users', sa.Column('email', sa.String(length=64), nullable=True))
+    op.create_index(op.f('ix_users_email'), 'users', ['email'], unique=True)
+    # ### end Alembic commands ###
+
+
+def downgrade():
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.drop_index(op.f('ix_users_email'), table_name='users')
+    op.drop_column('users', 'email')
+    # ### end Alembic commands ###

requirements.txt

@@ -4,6 +4,7 @@ Click==7.0
 dominate==2.3.4
 Flask==1.0.2
 Flask-Bootstrap==3.3.7.1
+Flask-Login==0.4.1
 Flask-Mail==0.9.1
 Flask-Migrate==2.2.1
 Flask-Moment==0.6.0