URL Shortener

A URL shortener is a tool that takes a long URL and converts it into a shorter, more manageable version without losing its ability to redirect to the original destination. Here is an explanation of how it works.

How does a URL shortener work?

1. Receiving the long URL: The process begins when a user inputs a full URL (for example, https://www.example.com/products/item?id=12345). The goal of the shortener is to create a shorter, easier-to-share alias.

2. Generating the short alias: The shortener’s server generates a unique alias (usually a combination of random characters, though it can sometimes be customized). This alias is assigned to the original URL and stored in a database. For example, the URL https://www.example.com/products/item?id=12345 might become something like https://url-shortener.vercel.app/abc123.

   • The alias can be generated using different algorithms:
     • Hashing: A hash is generated based on the URL.
     • Incremental IDs: The shortener uses unique IDs for each URL that increment with every new request.
     • Random character generation: Random strings of letters and numbers of fixed length are generated.

3. Storing in the database: The shortener stores both the long URL and its short alias in a database. Typically, additional data is stored, such as the creation date, number of clicks, and other relevant details.

4. Redirection: When a user clicks or enters the short URL in their browser (https://url-shortener.vercel.app/abc123), the shortener receives the request. It then looks up the alias in its database and retrieves the associated long URL. The server then sends an HTTP redirection (usually with a 301 or 302 code) to redirect the user to the original URL.

5. Statistics: Some URL shorteners offer detailed statistics, such as the number of clicks, user location, device used, and more. This data is collected with each redirection.

Benefits of a URL shortener

• Easier sharing: Short URLs are easier to share on social media, messages, and emails.
• Click tracking: Provides the ability to track the number of times the short link has been clicked.
• Customization: Some platforms allow you to customize the short URL, making it easier to remember.

Basic implementation example

Imagine a database with two main columns: one for the long URL and another for the short URL.

• Database:
  • Long URL: https://www.example.com/products/item?id=12345
  • Short URL: https://url-shortener.vercel.app/abc123

When the server receives a request for the short URL (https://url-shortener.vercel.app/abc123):

1. It looks up the long URL associated with abc123 in the database.
2. It redirects the user to https://www.example.com/products/item?id=12345.

Considerations

• Collisions: When random short URLs are generated, there is a risk that two different URLs could receive the same alias. To avoid this, strategies like uniqueness checks in the database are implemented.
• Security: Some shorteners include features to prevent redirection to malicious sites, such as blacklist checks or security scans.

In summary, a URL shortener takes a long address and converts it into a shorter, easier-to-share link while maintaining its original functionality through redirections. These systems can also include features for tracking clicks and analyzing link usage.