harshitshah436/token-service-api

token-service-api

A basic token management service using a user account and a transaction for sending and receiving tokens. This API is completely developed in NestJS.

Overview

Application functionality

• A token service consists of mainly two schemas: account and transaction to manage tokens.
  • account: {userEmail, status: ['active', 'locked'], createdAt, updatedAt}
  • transaction: {userEmail, amount (number of tokens), type: ['send', 'receive'], createdAt}
• A transaction can only be associated with one account. An account can be associated with many transactions.
• This API provides functionality to create, update, and delete user accounts and gets a current token balance for the user account. Similarly, it also provides endpoints to create, update and delete transactions.
• Some validations:
  • No account can have a negative balance
  • No transactions can be made for accounts with the status field set to 'locked'.

Technologies used

• NestJS - a progressive framework for building efficient, scalable Node.js server-side applications
• MongoDB - persistent database to store data and fast retrieval

Getting Started

Run application using Docker (Cloud-native) - Recommended

Prerequisites

• docker & docker-compose
  • Verify using the commands: docker -v & docker-compose -v

    $ docker -v
        Docker version 20.10.21, build baeda1f
    $ docker-compose -v
        Docker Compose version v2.13.0
    

Start application (Steps to Run)

In the project root directory, run:

docker compose up

Stop application

docker compose down

Restart containers with the new code

docker compose up --build

Run application locally in dev mode

Prerequisites

• node & npm
  • With the installation of the node, npm is by default installed.
  • Verify using the commands: node -v & npm -v
  • (Application tested on)

    $ npm -v
        9.5.1
    $ node -v
        v16.16.0
    

• MongoDB - run mongoDB documentation.

Start application (Steps to Run)

First, verify .env file in root. Then, in the project root directory, run:

npm ci
npm run start:dev

Explanation

• npm ci installs npm packages and creates node_modules directory. If npm ci gives any dependency error, use the npm install command instead of it.
• npm run start:dev command starts the nest application on port 3001.

Unit tests

Using jest, created unit tests for the accounts controller.

In the project root directory, run: npm test

Output:

$ npm test

> token-service-api@0.0.1 test
> jest

 PASS  src/accounts/accounts.controller.spec.ts
  Accounts Controller
    create()
      ✓ should create a new account (18 ms)
    findAll()
      ✓ should return an array of accounts (5 ms)
    filterByEmail()
      ✓ should return an account filtered by email (5 ms)
    update()
      ✓ should return an updated account (10 ms)
    delete()
      ✓ should return a deleted account (3 ms)
    getAccountWithCurrentBalancec()
      ✓ should return an account with a current balance (3 ms)

Test Suites: 1 passed, 1 total
Tests:       6 passed, 6 total
Snapshots:   0 total
Time:        4.261 s, estimated 7 s
Ran all test suites.

Open API (Swagger UI) docs

Once the application starts, Swagger UI will be available at http://localhost:3001/api.

Future Work/Enhancement

• Add authentication and role-based access
• For autogenerated OpenApi docs, add error responses.
• Introduce error handling and logging
• Implement e2e tests

Resources

• NestJS