Koinx Backend Developer Internship Assignment

Deployed Link: https://koinx-backend-internship-assignment.onrender.com/

Postman API's Collection: https://grey-station-125149-1.postman.co/workspace/koinx-public~2a6b5193-eb34-40c1-ae66-34ae587c820a/collection/21207467-0e42b0b5-3878-4f1b-924c-bb476abe80ec?action=share&creator=21207467

This project is a Node.js server application developed as part of assignment for the Koinx Backend Developer Internship. The application fetches cryptocurrency transactions for a user, stores them in a MongoDB database, retrieves Ethereum price data, and calculates the total expenses for the user's transactions.

Technologies Used
Project Setup
Environment Variables
API Endpoints
Cron Job
Author

Technologies Used

Node.js
Express.js
MongoDB (Mongoose)
Axios
Node-Cron
Etherscan API
CoinGecko API

================================================================

Project Setup

================================================================

Clone the Repository:

 git clone https://github.com/nandk4552/koinx_backend_internship_assignment.git
 cd koinx_backend_internship_assignment

Install Dependencies:
```
npm install
```

Set Up Environment Variables: Create a .env file in the root directory and add the following:

MONGO_URI=your_mongodb_connection_string
PORT=your_desired_port_number
ETHERSCAN_API_KEY=your_etherscan_api_key
JWT_SECRET=your_jwt_secret

Set Up Environment Variables:
```
npm run dev
```

The server will start on http://localhost:8080.

API Endpoints

[Note]: Before Accessing API create a user and login and use the token generated in headers with naming convention Bearer {paste token w/o braces}

Task 1: Fetch Crypto Transactions

Endpoint: GET /api/v1/transactions/:address Description: Fetches the list of "Normal" transactions for a given user address and stores them in the database.

Parameters: :address (string): The user's Ethereum address.

Response: Returns a list of transactions for the given address.

Example Request: GET /api/v1/transactions/0xce94e5621a5f7068253c42558c147480f38b5e0d

Task 2: Fetch and Store Ethereum Price in every 10 mins

Cron Job: This task is handled automatically by a cron job that runs every 10 minutes. Description: Fetches the current price of Ethereum in INR from the CoinGecko API and stores it in the database.

Endpoint: This task does not have a direct API endpoint as it is automated by the cron job.

Task 3: Get Total Expenses and Current Price

Endpoint: GET /api/v1/expenses/:address

Description: Calculates the total expenses for a user's transactions based on (gasUsed * gasPrice) / 1e18, retrieves the current Ethereum price, and returns both. Parameters: :address (string): The user's Ethereum address. Response: totalExpenses: The total expense for all transactions. currentEthereumPrice: The latest Ethereum price in INR. Example Request:

GET /api/v1/expenses/0xce94e5621a5f7068253c42558c147480f38b5e0d

Cron Job The cron job is set up to run every 10 minutes and fetch the current price of Ethereum. It logs the price and stores it in the MongoDB database.

nandk4552/koinx_backend_internship_assignment