URL shortener project with Python, Flask, MySQL

I started my career in cyber security, and now I’ve started learning Python development and automation. These things make me curious, and I love problem-solving and practicing with small projects.

I decided to do a project, but i don’t have idea. while i watch YouTube videos, one YouTuber, he had posted a video about url shortener. so i chose that as my first project

lets start

First we need to create a virtual environment

python3 -m venv venv

then activate that virtual environment

source venv/bin/activate

Then install some dependencies

sudo apt install python3-pip
pip3 install flask flask-mysqldb

let’s go to the coding part

from flask import Flask, request, redirect, render_template
from flask_mysqldb import MySQL
import random
import string

app = Flask(__name__)

• flask this is a core class for creating flask web application and
• request This is handling the HTTP request
• redirect This is helpful to url redirection
• render_templates this is helpful to rendering HTML files
• flask_mysqldb This MQSQL extension for Flask, this is make easier to connect with a MySQL database

app = Flask(__name__)

App is the object that represents your Flask web application

MYSQL configuration

# MySQL Configuration
app.config['MYSQL_HOST'] = 'localhost'
app.config['MYSQL_USER'] = 'root'
app.config['MYSQL_PASSWORD'] = 'cyber123/A'
app.config['MYSQL_DB'] = 'url_shortener'

• app.config['MYSQL_HOST'] = 'localhost' its defining where sql database is running
• app.config['MYSQL_USER'] = 'root' its defining mysql user name
• app.config['MYSQL_PASSWORD'] = 'cyber123/A' its defining mysql database password
• app.config['MYSQL_DB'] = 'url_shortener' its defining database name

lets write a random 6 digit code for generate short code

def generate_short_code(length=6):
    return ''.join(random.choices(string.ascii_letters + string.digits, k=length))

random.choices() generate a random lists, and string.ascii_letters this its randomly generate ascii charecters small and capital, string.digits this is generate random digit , and random.choices(string.ascii_letters + string.digits, k=length) this both compined generate ascii and digit makes 6 digit short code

app.route('/', methods=['GET', 'POST'])
def index():
    if request.method == 'POST':
        long_url = request.form['long_url']
        cur = mysql.connection.cursor()
        short_code = generate_short_code()
        
        # Insert into database
        cur.execute("INSERT INTO urls (long_url, short_code) VALUES (%s, %s)", (long_url, short_code))
        mysql.connection.commit()
        cur.close()
        
        short_url = request.host_url + short_code
        return render_template('index.html', short_url=short_url)
    return render_template('index.html')

in this code / its define this endpoint its use both GET , POST method

• POST method is used to submitting in a from, and generating short url.
• GET method is helpfull to display the form where users can enter their long url.

long_url = request.form['long_url']

this long_url access the value of input filed

cur = mysql.connection.cursor()

its help to create a connection to MYSQL, its help to execute SQL queries in MYSQL

short_code = generate_short_code()

its help to generate random shortcode urls

cur.execute("INSERT INTO urls (long_url, short_code) VALUES (%s, %s)", (long_url, short_code))

this this code is used to intert shortcode and url into database

mysql.connection.commit()

this is help to commit the transection, and save the changes in databse

cur.close()

Closes the database cursor after the operation is complete.

Redirect and route the URL shortener

@app.route('/<short_code>')
def redirect_url(short_code):
    cur = mysql.connection.cursor()
    cur.execute("SELECT long_url FROM urls WHERE short_code = %s", (short_code,))
    result = cur.fetchone()
    cur.close()
    
    if result:
        return redirect(result[0])
    else:
        return "URL not found", 404

@app.route('/<short_code>') this is getting long url from the database, this route take a dynamic short code , its part of url

cur = mysql.connection.cursor()
cur.execute("SELECT long_url FROM urls WHERE short_code = %s", (short_code,))

in this code cur create a connect to mysql and cur.execute("SELECT long_url FROM urls WHERE short_code = %s", (short_code,)) this get the suitable long url for short_urls

result = cur.fetchone() fetch the long url for short code

cur.close() close the cursor

if result:
        return redirect(result[0])
    else:
        return "URL not found", 404

in this code if result in database that redirect to the url, otherwize its show URL not found

thats it next we need to write code for index.html create a folder name /templates then create file inside this directory

Index.html

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>URL Shortener</title>
    <script src="https://cdn.tailwindcss.com"></script>
</head>
<body class="bg-gray-100 font-sans antialiased">

    <div class="flex items-center justify-center min-h-screen py-12 px-6">
        <div class="max-w-md w-full bg-white rounded-lg shadow-xl p-8">
            <h1 class="text-3xl font-semibold text-center text-indigo-600 mb-6">URL Shortener</h1>
            
            <!-- Form -->
            <form method="POST" class="space-y-4">
                <div class="flex flex-col">
                    <label for="long_url" class="text-lg font-medium text-gray-700">Enter URL</label>
                    <input type="url" name="long_url" class="px-4 py-2 border rounded-lg text-gray-800 focus:ring-2 focus:ring-indigo-400 focus:outline-none" required placeholder="Paste your long URL here">
                </div>
                
                <button type="submit" class="w-full py-2 bg-indigo-600 text-white font-semibold rounded-lg hover:bg-indigo-700 focus:ring-2 focus:ring-indigo-400">Shorten URL</button>
            </form>

            
        </div>
    </div>

</body>
</html>

i use tailwind css for styling , Tailwind is very easy to build mordern application quicly, i this case i used Tailwind CDN

and this is stores links in database

mysql> select * from urls;
+----+--------------------------------------------------------------------------------------+------------+
| id | long_url                                                                             | short_code |
+----+--------------------------------------------------------------------------------------+------------+
|  1 | https://aathilducky.com/posts/Interactive-Snake-Game-Using-OpenCV-&-Hand-Tracking/   | AWXoIO     |
|  2 | https://aathilducky.com/posts/Unlocking-the-Secrets-Information-picoCTF-Walkthrough/ | t36O06     |
|  3 | https://aathilducky.com/posts/Unlocking-the-Secrets-Information-picoCTF-Walkthrough/ | 0NhECT     |
|  4 | https://www.interngate.com/2025/03/software-engineering-intern-metana-sri.html       | U4gyxQ     |
+----+--------------------------------------------------------------------------------------+------------+

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