Link Shortener

Overview

This is a link shortener application built using Ruby on Rails that has test coverage and uses Postgres. The application takes into account scalability and is built to handle 1k new urls a day, where each url gets hit 20k times a day. Try out the application at this Heroku link.

Getting Started

How to set up the application on development server

• Run bundle install from the root directory to install ruby dependencies
• Run rails db:setup to setup the database
• Run bin/rails server or rails s to start a web server on your development machine to see/start the Rails application
• Navigate your browser to localhost:3000

Testing Link Shortener Rails Application

• Run rake db:test:load to recreate the test database from the current db/schema.rb
• On subsequent attempts, first run rake db:test:prepare to check for pending migrations
• Run rails test to run tests

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Documentation

Features

1. Root renders a form in which you can drop a URL. When you do, you'll get redirected to a page with its shortened URL and an admin URL.
2. When you go to a shortened URL, you get redirected to the original URL that was submitted, as long as the URL is active. Usage is also counted.
3. When you go to the Admin URL, you are given the ability to expire the shortened link and see how many times your link has been used. When a link has been expired, an empty 404 gets rendered.

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Database Schema

The database layer is very simple. It only has one table: it stores information about the URL mappings. To keep things simple, there is no user table to keep track of registered users. Meaning, there is no user registration implemented for this app.

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Link Shortener Request Flow Diagrams

Write Short Link

This diagram shows the request flow for creating a new shortened link. The user sends a request to the link shortener application, computes the business logic, which then writes to the postgreSQL database the new URL mapping/record.

Read Short Link

This diagram shows the request flow to request for the original URL from a shortened URL. The user sends the request to the application, which reads the original URL based on the unique shortened URL. If the shortened URL existed, then the client will receive an HTTP 302 Redirect Response. If the shortened URL did not exist, the user will receive an HTTP 404 Not Found response.

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Helpful Notes

System Design and Scaling Considerations

Some of the most interesting aspects of software engineering is figuring out the system design for the application and taking into account scalability as well. Some of the thoughts regarding these aspects of software engineering has been documented; see the System Design Considerations document for more information.