How to use Flask-Login with SQLite3

Python, Flask & SQLite3

Hi Everyone!!!

I have seen many tutorials on how to use Flask-Login with SQLAlchemy. On the other way, We can also use Flask-Login with SQLite3 Database.

where SQLite3 is 3x Faster than SQLAlchemy.

In this, I will be showing how to use SQLite3 Database with Flask-Login and This is one part of my project that I have done to show you.

Important Mention I use Raspberry Pi 3 for this project.

First, we install all the necessary software to get going,

1. Create a Python Virtual Environment.

sudo apt-get install python-virtualenv #Install Python virtual-env
cd /var/ # Navigate to var directory
mkdir www # Create directory named "www"
cd www
mkdir flask
cd flask
virtualenv flask-sqlite3 #Create the virtual-env "flask-sqlite3" 
. flask-sqlite3/bin/activate # To activate virtual-env
deactivate # To deactivate virtual-env

2. Install Flask, Flask-Login & wtforms.

. flask-sqlite3/bin/activate
pip install flask # Install Flask
pip install flask-login # Install flask-login
pip install flask-wtf # Install flask-wtf
pip install WTForms # Install WTForms

3. Install SQLite3.

apt-get install sqlite3 # Install sqlite3
sqlite3 login.db # Create a new sqlite database named "login"

“I have used Nginx as my webserver and Uwsgi as my Application Gateway”

Setup SQLite3

sqlite3 login.db

Now we will create a table named “login” to store all the login data in the database.

create table login(
user_id NUMBER PRIMARY KEY AUTOINCREMENT,
email text not null,
password text not null);

By, using Autoincrement the developer doesn't have to keep track of IDs while inserting details. It will automatically assign user_ids to each registered user.

“Use a registration form to insert login data into login.db”

I’m assuming that you have inserted some data into login data

insert into login values('xyz@gmail.com','XYZ123abc')

flask_login.py

nano flask.py # Create a new python file named "flask"
                              .  .  . 
from flask import Flask
from flask import render_template, url_for, flash, request, redirect, Response
import sqlite3
from flask_login import LoginManager, UserMixin, login_required, login_user, logout_user, current_user
from forms import LoginForm
app = Flask(__name__)
app.debug=True
login_manager = LoginManager(app)
login_manager.login_view = "login"
class User(UserMixin):
    def __init__(self, id, email, password):
         self.id = unicode(id)
         self.email = email
         self.password = password
         self.authenticated = False
    def is_active(self):
         return self.is_active()
    def is_anonymous(self):
         return False
    def is_authenticated(self):
         return self.authenticated
    def is_active(self):
         return True
    def get_id(self):
         return self.id
@login_manager.user_loader
def load_user(user_id):
   conn = sqlite3.connect('/var/www/flask/login.db')
   curs = conn.cursor()
   curs.execute("SELECT * from login where id = (?)",[user_id])
   lu = curs.fetchone()
   if lu is None:
      return None
   else:
      return User(int(lu[0]), lu[1], lu[2])
@app.route("/login", methods=['GET','POST'])
def login():
  if current_user.is_authenticated:
     return redirect(url_for('profile'))
  form = LoginForm()
  if form.validate_on_submit():
     conn = sqlite3.connect('/var/www/flask/login.db')
     curs = conn.cursor()
     curs.execute("SELECT * FROM login where email = (?)",    [form.email.data])
     user = list(curs.fetchone())
     Us = load_user(user[0])
     if form.email.data == Us.email and form.password.data == Us.password:
        login_user(Us, remember=form.remember.data)
        Umail = list({form.email.data})[0].split('@')[0]
        flash('Logged in successfully '+Umail)
        redirect(url_for('profile'))
     else:
        flash('Login Unsuccessfull.')
  return render_template('login.html',title='Login', form=form)
if __name__ == "__main__":
  app.run(host='0.0.0.0',port=8080,threaded=True)

forms.py

from flask_wtf import FlaskForm
from wtforms import StringField, PasswordField, SubmitField, BooleanField
from wtforms.validators import DataRequired, Length, Email, EqualTo, ValidationError
import sqlite3
class LoginForm(FlaskForm):
 email = StringField('Email',validators=[DataRequired(),Email()])
 password = PasswordField('Password',validators=[DataRequired()])
 remember = BooleanField('Remember Me')
 submit = SubmitField('Login')
 def validate_email(self, email):
    conn = sqlite3.connect('/var/www/flask/login.db')
    curs = conn.cursor()
    curs.execute("SELECT email FROM login where email = (?)",[email.data])
    valemail = curs.fetchone()
    if valemail is None:
      raise ValidationError('This Email ID is not registered. Please register before login')

Now we design the template using HTML & CSS for the login page.

mkdir templates # create a templates directory.
cd templates

html_template.html

<!DOCTYPE html>
<html lang="en">
<head>
<!-- Basic Page Needs
   -->
  <meta charset="utf-8">
  {% if title %}
   <title>{{ title }}</title>
  {% endif %}
<!-- Mobile Specific Metas
   -->
  <meta name="viewport" content="width=device-width, initial-scale=1 shrink-to-fit=no">
<!-- FONT
  -->    
  <link href="//fonts.googleapis.com/css?family=Raleway:400,300,600" rel="stylesheet" type="text/css">
<link rel="stylesheet" href="../static/css/normalize.css">
  <link rel="stylesheet" href="../static/css/skeleton.css">
<link rel="icon" type="image/png" href="../static/logo.png">
</head>
<body>
<!-- Primary Page Layout
   -->
<div style="margin-top:5%; margin-left:5%">
 <div style="width:100%;">
  <div style="width: 80%; height: 100px; float: left;">
     {% with messages = get_flashed_messages(with_categories=True)%}
 {% if messages %}
  {% for category, message in messages %}
   <div class="alert alert-{{ category }}">
    <h5>{{ message }}<h5>
   </div>
  {% endfor %}
 {% endif %}
     {% endwith %}
     {% block info %}
     {% endblock %}
  </div>
 </div>
</div>
<!-- End Document
   -->
</body>
</html>

I have used skeleton.css for the design

Refer to http://getskeleton.com/ “or” https://github.com/dhg/Skeleton

login.html

{% extends "html_template.html" %}
{% block info %}
 <form method='POST' action="">
  {{ form.hidden_tag() }}
  <fieldset class="form-group"> 
   <h1>Log In</h1>
   <div class="form-group">
    {{ form.email.label(class="form-control-label")}}
    {% if form.email.errors %}
     {{ form.email(class="form-control form-control-lg is-invalid") }}
     <div class="invalid-feedback">
      {% for error in form.email.errors %}
       <span>{{ error }}</span>
      {% endfor %}
     </div>
    {% else %}  
     {{ form.email(class="form-control form-control-lg")}}
    {% endif %}
   </div>
   <div class="form-group">
    {{ form.password.label(class="form-control-label")}}
    {% if form.password.errors %}
     {{ form.password(class="form-control form-control-lg is-invalid") }}
     <div class="invalid-feedback">
      {% for error in form.password.errors %}
       <span>{{ error }}</span>
      {% endfor %}
     </div>
    {% else %}
     {{ form.password(class="form-control form-control-lg")}}
    {% endif %}
   </div>
   <div class="form-group">
    {{ form.remember(class="form-check-input") }} 
    {{ form.remember.label(class="form-check-label") }}
   </div>
  </fieldset>
  <div class="form-group">
   {{ form.submit(class="btn btn-outline-info")}}
  </div>
  <a href="javascript:void(0)" onclick="location.href='/reset'">Forgot Password?</a>
 </form>
 <h6>Create an Account <a href="javascript:void(0)" onclick="location.href='/register'">Sign Up Now</a></h6>
{% endblock info %}

Now, Run the web app by,

python flask_login.py

Thank You to everyone who find it useful