URL Shortener Microservice

This repository implements URL Shortener Microservice for one of the FCC backend projects.

The service can be found running on Heroku

Running on Heroku

To run this app on Heroku, configure MongoDB add on and the following environment variables:

• MONGO_URI
• BASE_URL, example: BASE_URL=https://url-shortener-ellacodecamp.herokuapp.com

Design notes

This microservice was designed to use database for short URL identifier storage. It uses collection shorturl to store URL identifier in _id field and to store original URL in url field.

To keep URL identifier short, the original url is hashed using Murmur Hash algorithm (32 bit version) and the first 2 bytes of the result are used. The identifier is represented in hex format when it is returned to the user and therefore is only 4 characters long. If collision is detected, it is resolved by appending 01 to the identifier. If such identifier exists, this number gets incremented and appended to the original identifier as a hex string of even number of characters. The process is repeated till unused unique identifier is found for the original_url. I did not want to over engineer it too much for such a simple app. This was a simple way to guarantee URL identifier uniqueness.