URL shorteners are incredibly useful tools that convert long, unwieldy URLs into shorter, more manageable links. They are widely used in social media, marketing, and other digital platforms to make sharing links easier. In this article, we’ll walk through how to create a simple URL shortener using Python.
What is a URL Shortener?
A URL shortener is a service that takes a long URL and generates a shorter, unique alias for it. When users click on the shortened URL, they are redirected to the original, longer URL. Popular examples of URL shorteners include Bitly and TinyURL.
Tools and Libraries Required
To build our URL shortener, we’ll use the following Python libraries:
Flask: A lightweight web framework for Python that will help us create a web application.
Hashlib: A library that provides secure hash functions, which we’ll use to generate unique shortened URLs.
SQLite3: A lightweight database to store the original URLs and their shortened versions.
Step 1: Setting Up the Project
First, ensure you have Python installed on your system. Then, create a new directory for your project and set up a virtual environment:
mkdir url_shortener
cd url_shortener
python -m venv venv
source venv/bin/activate # On Windows, use `venv\Scripts\activate`Next, install the required libraries:
pip install FlaskStep 2: Creating the Flask Application
Create a new Python file, app.py, and start by importing the necessary libraries:
from flask import Flask, request, redirect, render_template
import hashlib
import sqlite3
app = Flask(__name__)Step 3: Setting Up the Database
We’ll use SQLite3 to store the original URLs and their shortened versions. Create a function to initialize the database:
def init_db():
conn = sqlite3.connect('urls.db')
c = conn.cursor()
c.execute('''CREATE TABLE IF NOT EXISTS urls
(id INTEGER PRIMARY KEY AUTOINCREMENT,
original_url TEXT NOT NULL,
short_url TEXT NOT NULL)''')
conn.commit()
conn.close()
init_db()Step 4: Generating Short URLs
To generate a short URL, we’ll use a hash function. Here’s a function that takes a long URL and returns a shortened version:
def generate_short_url(url):
hash_object = hashlib.md5(url.encode())
return hash_object.hexdigest()[:8]Step 5: Creating Routes
Now, let’s create the routes for our Flask application. We’ll need two main routes:
Home Route: Displays a form where users can input a long URL.
Redirect Route: Handles the shortened URL and redirects users to the original URL.
Here’s the code for the routes:
@app.route('/', methods=['GET', 'POST'])
def home():
if request.method == 'POST':
original_url = request.form['url']
short_url = generate_short_url(original_url)
conn = sqlite3.connect('urls.db')
c = conn.cursor()
c.execute("INSERT INTO urls (original_url, short_url) VALUES (?, ?)",
(original_url, short_url))
conn.commit()
conn.close()
return f"Shortened URL: {request.host_url}{short_url}"
return render_template('index.html')
@app.route('/<short_url>')
def redirect_to_url(short_url):
conn = sqlite3.connect('urls.db')
c = conn.cursor()
c.execute("SELECT original_url FROM urls WHERE short_url=?", (short_url,))
result = c.fetchone()
conn.close()
if result:
return redirect(result[0])
return "URL not found", 404Step 6: Creating the HTML Template
Create a folder named templates in your project directory and add a file named 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>
</head>
<body>
<h1>URL Shortener</h1>
<form method="POST">
<input type="text" name="url" placeholder="Enter your URL" required>
<button type="submit">Shorten</button>
</form>
</body>
</html>Step 7: Running the Application
Finally, run the Flask application:
export FLASK_APP=app.py
flask runVisit http://127.0.0.1:5000/ in your browser, and you’ll see the URL shortener in action!
Conclusion
In this tutorial, we’ve built a simple URL shortener using Python, Flask, and SQLite3. This is a basic implementation, but you can expand it by adding features like custom short URLs, analytics, or a user interface for managing links.
Happy coding!