In this tutorial, we’ll be creating a complete login and registration system with Python Flask and MySQL.
The Basic and Advanced packages include additional features and a download link to the source code.
There are a few steps we need to take before we create our python login and registration system, we need to download and set up Python and the packages we’re going to use.
We need to create our project directory and files, you can put the directory anywhere on your computer, as long as Python can access it, create the directories and files below.
\-- pythonlogin
|-- main.py
\-- static
|-- style.css
\-- templates
|-- index.html
|-- register.html
|-- home.html
|-- profile.html
|-- layout.html
Each file will contain the following:
The below instruction will start your web server (Windows):
Debug mode will allow us to edit our files without constantly restarting the web server.
MySQL Workbench is a GUI for creating and editing our databases, follow the below instructions.
CREATE DATABASE IF NOT EXISTS `pythonlogin` DEFAULT CHARACTER SET utf8 COLLATE utf8_general_ci;
USE `pythonlogin`;
CREATE TABLE IF NOT EXISTS `accounts` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`username` varchar(50) NOT NULL,
`password` varchar(255) NOT NULL,
`email` varchar(100) NOT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=2 DEFAULT CHARSET=utf8;
INSERT INTO `accounts` (`id`, `username`, `password`, `email`) VALUES (1, 'test', 'test', 'test@test.com');
The above SQL statement will create our database pythonlogin with the table accounts, it will also insert a test account, this account we’ll use for testing purposes later in the tutorial, it will make sure everything is working as it should.
Edit the style.css file and add the following:
* {
box-sizing: border-box;
font-family: -apple-system, BlinkMacSystemFont, "segoe ui", roboto, oxygen, ubuntu, cantarell, "fira sans", "droid sans", "helvetica neue", Arial, sans-serif;
font-size: 16px;
-webkit-font-smoothing: antialiased;
-moz-osx-font-smoothing: grayscale;
}
body {
background-color: #435165;
margin: 0;
}
.login, .register {
width: 400px;
background-color: #ffffff;
box-shadow: 0 0 9px 0 rgba(0, 0, 0, 0.3);
margin: 100px auto;
}
.login h1, .register h1 {
text-align: center;
color: #5b6574;
font-size: 24px;
padding: 20px 0 20px 0;
border-bottom: 1px solid #dee0e4;
}
.login .links, .register .links {
display: flex;
padding: 0 15px;
}
.login .links a, .register .links a {
color: #adb2ba;
text-decoration: none;
display: inline-flex;
padding: 0 10px 10px 10px;
font-weight: bold;
}
.login .links a:hover, .register .links a:hover {
color: #9da3ac;
}
.login .links a.active, .register .links a.active {
border-bottom: 3px solid #3274d6;
color: #3274d6;
}
.login form, .register form {
display: flex;
flex-wrap: wrap;
justify-content: center;
padding-top: 20px;
}
.login form label, .register form label {
display: flex;
justify-content: center;
align-items: center;
width: 50px;
height: 50px;
background-color: #3274d6;
color: #ffffff;
}
.login form input[type="password"], .login form input[type="text"], .login form input[type="email"], .register form input[type="password"], .register form input[type="text"], .register form input[type="email"] {
width: 310px;
height: 50px;
border: 1px solid #dee0e4;
margin-bottom: 20px;
padding: 0 15px;
}
.login form input[type="submit"], .register form input[type="submit"] {
width: 100%;
padding: 15px;
margin-top: 20px;
background-color: #3274d6;
border: 0;
cursor: pointer;
font-weight: bold;
color: #ffffff;
transition: background-color 0.2s;
}
.login form input[type="submit"]:hover, .register form input[type="submit"]:hover {
background-color: #2868c7;
transition: background-color 0.2s;
}
.navtop {
background-color: #2f3947;
height: 60px;
width: 100%;
border: 0;
}
.navtop div {
display: flex;
margin: 0 auto;
width: 1000px;
height: 100%;
}
.navtop div h1, .navtop div a {
display: inline-flex;
align-items: center;
}
.navtop div h1 {
flex: 1;
font-size: 24px;
padding: 0;
margin: 0;
color: #eaebed;
font-weight: normal;
}
.navtop div a {
padding: 0 20px;
text-decoration: none;
color: #c1c4c8;
font-weight: bold;
}
.navtop div a i {
padding: 2px 8px 0 0;
}
.navtop div a:hover {
color: #eaebed;
}
body.loggedin {
background-color: #f3f4f7;
}
.content {
width: 1000px;
margin: 0 auto;
}
.content h2 {
margin: 0;
padding: 25px 0;
font-size: 22px;
border-bottom: 1px solid #e0e0e3;
color: #4a536e;
}
.content > p, .content > div {
box-shadow: 0 0 5px 0 rgba(0, 0, 0, 0.1);
margin: 25px 0;
padding: 25px;
background-color: #fff;
}
.content > p table td, .content > div table td {
padding: 5px;
}
.content > p table td:first-child, .content > div table td:first-child {
font-weight: bold;
color: #4a536e;
padding-right: 15px;
}
.content > div p {
padding: 5px;
margin: 0 0 10px 0;
}
Feel free to customize the stylesheet, change text color, font sizes, content width, etc. This stylesheet will be used for all our pages (login, registration, home, and profile pages).
We can finally start coding with Python! What we’ll do in this part is create the login template, connect to MySQL database, login authentication, and create session variables.
The first thing we need to do is import the packages we’re are going to use, edit the main.py file and add the following:
from flask import Flask, render_template, request, redirect, url_for, session
from flask_mysqldb import MySQL
import MySQLdb.cursors
import re
Now we need to create some variables and configure the MySQL connection details.
Add after the above code:
app = Flask(__name__)
# Change this to your secret key (can be anything, it's for extra protection)
app.secret_key = 'your secret key'
# Enter your database connection details below
app.config['MYSQL_HOST'] = 'localhost'
app.config['MYSQL_USER'] = 'root'
app.config['MYSQL_PASSWORD'] = ''
app.config['MYSQL_DB'] = 'pythonlogin'
# Intialize MySQL
mysql = MySQL(app)
Make sure you change the MySQL details to your own details and change the secret key.
Now we can create the login page, to do that we need to create a new route.
Add after the above code:
# http://localhost:5000/pythonlogin/ - this will be the login page, we need to use both GET and POST requests
@app.route('/pythonlogin/', methods=['GET', 'POST'])
def login():
return render_template('index.html', msg='')
Edit the index.html file and add:
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>Login</title>
<link rel="stylesheet" href="{{ url_for('static', filename='style.css') }}">
<link rel="stylesheet" href="https://use.fontawesome.com/releases/v5.7.1/css/all.css">
</head>
<body>
<div class="login">
<h1>Login</h1>
<div class="links">
<a href="{{ url_for('login') }}" class="active">Login</a>
<a href="#">Register</a>
</div>
<form action="{{ url_for('login') }}" method="post">
<label for="username">
<i class="fas fa-user"></i>
</label>
<input type="text" name="username" placeholder="Username" id="username" required>
<label for="password">
<i class="fas fa-lock"></i>
</label>
<input type="password" name="password" placeholder="Password" id="password" required>
<div class="msg">{{ msg }}</div>
<input type="submit" value="Login">
</form>
</div>
</body>
</html>
As you can see with the login template we create the form with the input fields: username and password, and the form’s method is set to post, this will send the form data to our Python Flask server using a POST request.
If we navigate to http://localhost:5000/pythonlogin/ in our web browser it will look like the following:
If you click the Login button nothing will happen or will return an error, that’s because we haven’t yet set up the POST request that will process the form data.
Now we need to go back to our main.py file and add the authentication code to our route function that we created.
After:
def login():
Add:
# Output message if something goes wrong...
msg = ''
# Check if "username" and "password" POST requests exist (user submitted form)
if request.method == 'POST' and 'username' in request.form and 'password' in request.form:
# Create variables for easy access
username = request.form['username']
password = request.form['password']
With the code above we use an if statement to check if the requested method is POST and check if the username and password exist in the form request, if they both exist the username and password variables will be created.
Add after:
# Check if account exists using MySQL
cursor = mysql.connection.cursor(MySQLdb.cursors.DictCursor)
cursor.execute('SELECT * FROM accounts WHERE username = %s AND password = %s', (username, password))
# Fetch one record and return result
account = cursor.fetchone()
The code above will select the account from our accounts table in our MySQL database with the username and password that the user entered in the login form.
Add after:
# If account exists in accounts table in out database
if account:
# Create session data, we can access this data in other routes
session['loggedin'] = True
session['id'] = account['id']
session['username'] = account['username']
# Redirect to home page
return 'Logged in successfully!'
else:
# Account doesnt exist or username/password incorrect
msg = 'Incorrect username/password!'
This will check if the account exists, if it does we create new session variables, these session variables will be remembered for the user, we can use them to determine if the user is logged in or not.
Session variables act like cookies, they will be remembered on the server instead of the user’s browser, only the session ID will be stored as a browser cookie.
If the account doesn’t exist we can simply show an error on the login form.
Your login route should look like the following:
@app.route('/pythonlogin/', methods=['GET', 'POST'])
def login():
# Output message if something goes wrong...
msg = ''
# Check if "username" and "password" POST requests exist (user submitted form)
if request.method == 'POST' and 'username' in request.form and 'password' in request.form:
# Create variables for easy access
username = request.form['username']
password = request.form['password']
# Check if account exists using MySQL
cursor = mysql.connection.cursor(MySQLdb.cursors.DictCursor)
cursor.execute('SELECT * FROM accounts WHERE username = %s AND password = %s', (username, password))
# Fetch one record and return result
account = cursor.fetchone()
# If account exists in accounts table in out database
if account:
# Create session data, we can access this data in other routes
session['loggedin'] = True
session['id'] = account['id']
session['username'] = account['username']
# Redirect to home page
return 'Logged in successfully!'
else:
# Account doesnt exist or username/password incorrect
msg = 'Incorrect username/password!'
# Show the login form with message (if any)
return render_template('index.html', msg=msg)
To make sure everything is working correctly navigate to http://localhost:5000/pythonlogin/ and input “test” in both the username and password fields, and then click the Login button, you should receive a message that outputs “Logged in successfully!”.
For a user to log out all we have to do is remove the session variables that were created when the user logs in.
Add the following code to the main.py file:
# http://localhost:5000/python/logout - this will be the logout page
@app.route('/pythonlogin/logout')
def logout():
# Remove session data, this will log the user out
session.pop('loggedin', None)
session.pop('id', None)
session.pop('username', None)
# Redirect to login page
return redirect(url_for('login'))
This will remove each session variable, without these session variables the user cannot be logged in. And then redirect the user to the login page.
To log out we can navigate to the following URL: http://localhost:5000/pythonlogin/logout
We need a registration system so users can register on our app, what we’ll do in this part is create a new register route and create the registration template.
Edit the register.html file and add:
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>Register</title>
<link rel="stylesheet" href="{{ url_for('static', filename='style.css') }}">
<link rel="stylesheet" href="https://use.fontawesome.com/releases/v5.7.1/css/all.css">
</head>
<body>
<div class="register">
<h1>Register</h1>
<div class="links">
<a href="{{ url_for('login') }}">Login</a>
<a href="{{ url_for('register') }}" class="active">Register</a>
</div>
<form action="{{ url_for('register') }}" method="post" autocomplete="off">
<label for="username">
<i class="fas fa-user"></i>
</label>
<input type="text" name="username" placeholder="Username" id="username" required>
<label for="password">
<i class="fas fa-lock"></i>
</label>
<input type="password" name="password" placeholder="Password" id="password" required>
<label for="email">
<i class="fas fa-envelope"></i>
</label>
<input type="email" name="email" placeholder="Email" id="email" required>
<div class="msg">{{ msg }}</div>
<input type="submit" value="Register">
</form>
</div>
</body>
</html>
This is a basic registration template we’ll use to register users, it’s identical to the login template but also includes the Email field.
The form’s action attribute is set to the “register” route, we’ll use this route to handle the POST request.
Now that we have our template created we can begin to create the “register” route, this will handle the POST request and insert a new account into our accounts table, only if the submitted fields are valid that is.
Go back to the main.py file and add the following:
# http://localhost:5000/pythinlogin/register - this will be the registration page, we need to use both GET and POST requests
@app.route('/pythonlogin/register', methods=['GET', 'POST'])
def register():
# Output message if something goes wrong...
msg = ''
# Check if "username", "password" and "email" POST requests exist (user submitted form)
if request.method == 'POST' and 'username' in request.form and 'password' in request.form and 'email' in request.form:
# Create variables for easy access
username = request.form['username']
password = request.form['password']
email = request.form['email']
elif request.method == 'POST':
# Form is empty... (no POST data)
msg = 'Please fill out the form!'
# Show registration form with message (if any)
return render_template('register.html', msg=msg)
We create the “register” route and check if all the submitted form fields exist, if they don’t output a simple error.
After:
email = request.form['email']
Add:
# Check if account exists using MySQL
cursor = mysql.connection.cursor(MySQLdb.cursors.DictCursor)
cursor.execute('SELECT * FROM accounts WHERE username = %s', (username))
account = cursor.fetchone()
# If account exists show error and validation checks
if account:
msg = 'Account already exists!'
elif not re.match(r'[^@]+@[^@]+\.[^@]+', email):
msg = 'Invalid email address!'
elif not re.match(r'[A-Za-z0-9]+', username):
msg = 'Username must contain only characters and numbers!'
elif not username or not password or not email:
msg = 'Please fill out the form!'
else:
# Account doesnt exists and the form data is valid, now insert new account into accounts table
cursor.execute('INSERT INTO accounts VALUES (NULL, %s, %s, %s)', (username, password, email))
mysql.connection.commit()
msg = 'You have successfully registered!'
The above code will select an account with the submitted username and password fields, if the account doesn’t exist we can validate the data, the validation will check if the submitted email is valid and check if the username contains only letters and numbers.
If everything checks out the code will insert a new account into our accounts tables.
To test that it is working correctly navigate to http://localhost:5000/pythonlogin/register and fill out the form and click the Register button, you should get the following response:
Users can now register and login to our app, next we’ll create a basic home page for logged-in users.
The home page will be for logged-in users only, this will be just a basic example, you can work from this and create more pages.
Edit main.py and add the following:
# http://localhost:5000/pythinlogin/home - this will be the home page, only accessible for loggedin users
@app.route('/pythonlogin/home')
def home():
# Check if user is loggedin
if 'loggedin' in session:
# User is loggedin show them the home page
return render_template('home.html', username=session['username'])
# User is not loggedin redirect to login page
return redirect(url_for('login'))
This will create the home route function, if the user is logged in they will have access to the home page, if not redirect them to the login page.
Edit the home.html file and add the following:
{% extends 'layout.html' %}
{% block title %}Home{% endblock %}
{% block content %}
<h2>Home Page</h2>
<p>Welcome back, {{ username }}!</p>
{% endblock %}
We also need to create the layout for our logged-in pages, edit the layout.html file and add:
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>{% block title %}{% endblock %}</title>
<link rel="stylesheet" href="{{ url_for('static', filename='style.css') }}">
<link rel="stylesheet" href="https://use.fontawesome.com/releases/v5.7.1/css/all.css">
</head>
<body class="loggedin">
<nav class="navtop">
<div>
<h1>Website Title</h1>
<a href="{{ url_for('home') }}"><i class="fas fa-home"></i>Home</a>
<a href="{{ url_for('profile') }}"><i class="fas fa-user-circle"></i>Profile</a>
<a href="{{ url_for('logout') }}"><i class="fas fa-sign-out-alt"></i>Logout</a>
</div>
</nav>
<div class="content">
{% block content %}{% endblock %}
</div>
</body>
</html>
Now we can easily use the same layout for both the home and profile pages.
Currently, when a user logs in there will be a basic output message, we can now change that to redirect to our new home page instead, find the following code in the login route function:
return 'Logged in successfully!'
Replace with:
return redirect(url_for('home'))
The user will now be redirected to the home page when they log in, enter the test details into the login form and click the Login button, you should see the following:
This is just a simple home page that you can work from, next we’ll create the profile page and display the user’s details.
The profile page is where the user can go to view their details (username, password, and email).
Add the following route to the main.py file:
# http://localhost:5000/pythinlogin/profile - this will be the profile page, only accessible for loggedin users
@app.route('/pythonlogin/profile')
def profile():
# Check if user is loggedin
if 'loggedin' in session:
# We need all the account info for the user so we can display it on the profile page
cursor = mysql.connection.cursor(MySQLdb.cursors.DictCursor)
cursor.execute('SELECT * FROM accounts WHERE id = %s', [session['id']])
account = cursor.fetchone()
# Show the profile page with account info
return render_template('profile.html', account=account)
# User is not loggedin redirect to login page
return redirect(url_for('login'))
This will create the profile route and select all the account details from the database if the user is logged in.
Edit the profile.html file and add:
{% extends 'layout.html' %}
{% block title %}Profile{% endblock %}
{% block content %}
<h2>Profile Page</h2>
<div>
<p>Your account details are below:</p>
<table>
<tr>
<td>Username:</td>
<td>{{ account['username'] }}</td>
</tr>
<tr>
<td>Password:</td>
<td>{{ account['password'] }}</td>
</tr>
<tr>
<td>Email:</td>
<td>{{ account['email'] }}</td>
</tr>
</table>
</div>
{% endblock %}
This will extend the layout (layout.html) file that we created previously, if you navigate to the profile page it will look like the following:
That’s basically it for the home and profile pages, the Advanced package includes the edit profile feature, this will allow the user to change their username, password, and email.
Congratulations! You’ve created your own login and registration system with Python Flask and MySQL. You’re free to use the source code in your application(s).
#python #mysql