URL shortener with a JSON RESTful API containing 3 endpoints.

• GET method that redirects the user to the original URL.
• POST method to create a shortened URL
• GET method to return the app statistics

Execute migration script in first build:
docker-compose up --detach --build; docker-compose exec app npm run tables:create

To seed the database with short URL id:example and statistic data for period:weeks execute npm script:
npm run tables:seedWeeks

Localhost environment variables
Create a .env file in the root of the project and populate it with variables:

DATABASE_URL=
REDIS_URL=
SERVER_PORT=
HOST=
NODE_ENV=development

Accepts an optional short property that defines what the shortened URL should look like
If no short property was passed, pseudo-randomly generated string is used for ID

[POST] URI: `/api/shorten`  

Redirects to the full-size URL

[GET] URI: `/:id`  

Returns valid data containing app usage statistics.

[GET] URI: `/api/statistics/:id`  

Instead of connecting to database on every request, Redis is used as a cache layer. Redis keys are checked first, and then if data is not found on Redis, server connects to the Database and fetches the data.

To prevent many connections to the database, Redis is used as a data aggregator. When a user uses a short URL, the backend increases Redis correlated keys to that short URL and increases them by 1, also Redis sets the timer key to expire in N milliseconds.
After the timer key expires, Redis publishes an event that tigers the job which persists Redis data into a database.