crypto-wallet

A demo crypto wallet app using with teaching purposes. This app allows clients to manage their crypto currency portfolio. It uses Coinmarketcap API for getting the updated cryptocurrencies quotation.

It provides the following functionalities:

• managing users (CRUD operations, uses for admins)
• buy, sell and transfer cryptocurrencies
• allow users to see their portfolio balance (the quotation of their cryptocurrencies portfolio converted to USD)
• allows users to see their transaction history

Tech Stack

• Java 17
• Spring Boot
• Postgres
• Docker

Architecture

The following diagram shows the systems architecture:

Data Model

The following diagram shows the data model:

Run the app

1. Start containers using docker compose:

docker-compose up

2. Run the application

You'll need to have configured the following env variables before running the app:

• DB_URL
• DB_USER
• DB_PASSWORD
• COINMARKETCAP_URL: Coinmaerkap api url
• COINMARKETCAP_API_KEY: you have to generate one API KEY on Coinmaketcap Web Site

Then execute:

./gradlew bootRun

It runs the application on http://localhost:8080

Database migrations

We use Flyway for database migrations. It runs the migration on application startup, so remember to have the dockers up when running the app.

API

• Healthcheck

curl -i -H "Accept: application/json" -H "Content-Type: application/json" -X GET http://localhost:8080/healthcheck

• Get user by id

curl -i -H "Accept: application/json" -H "Content-Type: application/json" -X GET http://localhost:8080/users/:userId

• Get all users

curl -i -H "Accept: application/json" -H "Content-Type: application/json" -X GET http://localhost:8080/users

• Create user

curl -X POST -H "Content-Type: application/json" \
	-d '{"username": "pepe", "password": "pass1234", "email": "[email protected]"}' \
	http://localhost:8080/users

• Update user

curl -X PUT -H "Content-Type: application/json" \
	-d '{"username": "pepe", "password": "pass1234", "email": "[email protected]"}' \
	http://localhost:8080/users/:userId

• Delete user

curl -X "DELETE" http://localhost:8080/users/:userId

• Get quotes

curl -i -H "Accept: application/json" -H "Content-Type: application/json" -X GET http://localhost:8080/cryptocurrencies/quotes

• Get portfolio

curl -i -H "Accept: application/json" -H "Content-Type: application/json" -X GET http://localhost:8080/portfolios/:userId

• Get transaction history

curl -i -H "Accept: application/json" -H "Content-Type: application/json" -X GET http://localhost:8080/transactions/8

• Transfer

curl -X POST -H "Content-Type: application/json" \
	-d '{"issuer": "88", "receiver": "2", "cryptocurrency": "Huobi Token", "amount": 10}' \
	http://localhost:8080/transactions/transferences

• Buy

curl -X POST -H "Content-Type: application/json" \
	-d '{"userId": 3, "cryptocurrency": "Bitcoin", "amountInUsd": 100000}' \
	http://localhost:8080/transactions/buys

• Sell

curl -X POST -H "Content-Type: application/json" \
	-d '{"userId": 3, "cryptocurrency": "Bitcoin", "amount": 1}' \
	http://localhost:8080/transactions/sells

Formatting & Coding Style

This project uses Spotless to enforce a consistent programming style. Under the hood, it is configured to use Google Java Format. We have the following commands:

• check formatting violations:

./gradlew spotlessCheck

• apply formatting:

./gradlew spotlessApply

By default, this plugin is attached to the verify phase of maven lifecycle.

Extra notes

• A ready docker-compose is provided. It contains all the components ready for local development. It also contains dummy data for playing around with the app.

• Also, a postman collection is provided.