zenbakiak / ellink-api

Ell.ink url shortener api (Assessment)

README

This project is an assessment.

Description

This is the API of the shortener URL created with Rails (backend) and ReactJS (frontend).

How it works

It works by just parsing and extracting information from the URL you want to shrink, then we save this record in our database with a special shortcode, it is the parameter you will see in the URL, e.g. https://ell.ink/AcDR51o

The mentioned code bellow is based on combinations and permutations.

First, we generate a number based on current time (with milliseconds) and randomize our dictionary, which is a string composed by the alphabet in lower and upper case, as well as 0-9 digits, so, we have a total of 62 possible values in each position of our 7 length string

abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890

so, our method consists of a series of modulus from divisions of the generated number by the length of our alphabet

To achieve more complexity and reliability we could use libraries sich as hashids or nanoid, they achieve their results by implementing the Fisher-Yates shuffle algorithm

references:

https://hashids.org/

https://en.wikipedia.org/wiki/Fisher%E2%80%93Yates_shuffle

However, by taking advantage of ruby and the Array#shuffle method, we can gain time by not using the algorithm, just need to be sure the alphabet is shuffling every time we generate a code.

With that in mind, we have a nPr permutation whee n = 62, r = 7

62! / (62-7)! = 2.478652606E+12, = 2478652606080 possible ids.

To start application:

• Clone this repo
• bundle install

• Ruby version:

  ruby 2.6.5p114

• System dependencies:

  • Postgres.

• Database creation

  Ensure you have your config/database.yml file correctly, then run rake db:create

• Database initialization:

  rake db:setup *

  * this will create the database an run migrations and seeds.

• How to run the test suite

  rspec

  rubocop to check code offenses

  Also check for the coverage/index.html for a testing coverage report.

• To deploy on heroku:

  • heroku create

  • git push heroku master

  • heroku run rake db:migrate

Author:

@zenbakiak