Buycoins Engineering Challenge

A solution to the Buycoins backend engineering challenge

About This Project

The project is a GraphQL API that collects users' banking details and fetch their bank account name from the Paystack API. The program also calculates the levenshtein distance between a user-supplied name and the Paystack-supplied name, so it can still verify user's in cases of simple misspellings.

Major Assumptions On Inplementation

• While building, I assumed there is already an existing user who is trying to add the bank account (as stated in the Challenge documentation), hence I created a users table in the DB with a name and is_verified attribute.

Use Case For Pure Levenshtein Distance (LD) Over Damerau–Levenshtein Distance (Damerau-LD) In This Scenario

Since we need to keep our edit distance to within 2, targeted at instances where not more than two letters are misplaced, the Pure LD handles this better. If there are 4 misplaced letters, the Pure LD returns an edit distance of 4, which fails our use case as expected. However, the Damerau-LD will return 2 and verify a user, which betrays our use case. For instance, If a user inputs Pyastcak instead of Paystack, the Damerau-LD will return 2 and verify the user (which we do not want), while the Pure LD returns 4 and declines verification (as expected).

Built With

• Ruby v3.0.0
• Ruby on Rails 6
• GraphQL
• Paystack API

Set up Project

• Install git
• Install the Ruby programming language, if you haven't already.
• • Install the Ruby on Rails MVC Framework, if you haven't already.
• Open Terminal
• Navigate to the preferred location/folder you want the app on your local machine. Use cd <file-path> for this.
• Run git clone https://github.com/Moreneecoder/buycoins-challenge.git to download the project source code.
• Now that you have a local copy of the project, navigate to the root of the project folder from your terminal.
• Run bundle install to install all dependencies in the Gemfile file.

Set up Database

• This project uses postgresql, so ensure you have that installed first
• Run the commands below to create and migrate database

   rails db:create
   rails db:reset
   rails db:migrate

Other Dependencies

• Paystack Bank Resolution API: Bank account resolution is handled by Paystack, to set this up, create an account and enter the details of your paystack test api secret key in the .env file as detailed further below.

• Install the gem dotenv-rails.

• Create .env file in the project root directory to locally store/use your Paystack APIs like so:

PAYSTACK_SECRET=<YOUR_PAYSTACK_SECRET_KEY>

🗣 NOTE: All PAYSTACK API KEYS can be found in your Paystack dashboard, under Settings.

Running Tests

• RSpec: This is a tool for testing the effectiveness of the program's logic at every step. To set up RSpec:
  • run gem install rspec in your terminal. This should install rspec globally on your local machine.
  • run rspec --version. This should display your rspec version if successfully installed.
  • run rspec to see passing and failing tests.

Usage

• Start server with: rails server

• Open http://localhost:3000/graphiql in your browser to access a query enviroment.

Authors

👤 Bello Morenikeji Fuad

• GitHub: @moreenecoder
• Twitter: @mo_bello19
• LinkedIn: Morenikeji Bello

Acknowledgments

Buycoins Africa

📝 License

This project is MIT licensed.