Etherscan Backend

Overview

This project is a backend service for interacting with Ethereum blockchain data. It fetches block data and stores it in a MongoDB database for further analysis.

Features

• Fetches the latest block from the Ethereum blockchain.
• Provides details of the last ‘n’ blocks.
• Retrieves account details of a particular address, including ETH balance and last ‘n’ transactions.
• Fetches details of different ERC20 tokens provided their addresses.
• All data is fetched from the Ethereum mainnet.
• On server startup, it fetches the last 100 blocks and stores them in MongoDB. New blocks are added automatically to the database.
• If the value of ‘n’ in the second requirement doesn’t exceed the number of blocks stored already in the database, data is fetched from the database itself.
• Dockerized for easy deployment using docker-compose up.

Prerequisites

• Node.js (version 14 or later)
• npm (Node package manager)
• MongoDB (for local development)
• Docker (for containerized deployment)

Getting Started

Running Locally

1. Clone the repository
2. Install dependencies: npm install
3. Create a .env file in the root directory with the following content:

• ETHERSCAN_API_KEY=YOUR_API_KEY_HERE

• MONGODB_URI=mongodb://localhost:27017/etherscan

• INFURA_URL=https://mainnet.infura.io/v3/YOUR_INFURA_PROJECT_ID

4. Start the application: npm run dev
5. Access the application at http://localhost:3000.

Running with Docker

1. Ensure Docker is installed and running on your machine.
2. Build and start the containers: docker-compose up --build
3. Access the application at http://localhost:3000.
4. Connect to MongoDB using Compass at mongodb://localhost:27017/etherscan.

Testing Endpoints with Postman

You can test the following endpoints using Postman:

1. Get Latest Block

• Endpoint: GET /api/latest-block
• Description: Retrieves the latest block information.

2. Get Last n Blocks

• Endpoint: GET /api/blocks/n
• Description: Retrieves details of the last 'n' blocks.

3. Get Account Details

• Endpoint: GET /api/account/:address
• Description: Retrieves account details including ETH balance and last 'n' transactions.

4. Get ERC20 Token Details

• Endpoint: GET /api/token/:address
• Description: Retrieves details of a specific ERC20 token by its address.

Project Screenshots

1. Application Running Locally:

2. MongoDB Compass:

3. Docker Logs:

4. Docker Setup:

5. Postman Testing: