Cryptologic BE Challenge

Backend application writen in Nodejs/Typescript with simple REST architecture. Implemented the ethers.js library to manage the RPC connection, fetch transactions data and utils.

Contains:

1. RPC Connection to Avalanche EVM C-Chain
2. Local MongoDB connection
3. Middlewares on endpoint routes

Endpoints Description:

• GET: transaction from RPC by txHash and contract detail /api/detail/:txHash

• POST: save transaction fetched from RPC to the DB api/transaction/
  Body json example:

  {
      "txHash": 0x508217c172c3cfe006ee9ca5bef621ba11a359461bacfc0494f1449a7d00f443
  }
  

• GET: get transaction by txHash with decode BigNumbers api/:txHash]

• GET: get all saved transactions from the DB with decode BigNumbers api/transaction/get-all

• GET: get ABI from server /contract/abi

• GET: get ABI from server /contract/bytecode

Packages

1. Ethers
2. Express
3. MongoDB
4. ts-node

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Challenge

✅ Use web3.js or ethers.js proper methods to fetch transaction data details

✅ Fetch and save main contract ABI and bytecode and save them into a file and database

✅ Understand and parse the event log to show in a básic REST response the decoded events and its parameters

✅ Create a basic REST endpoint that once queried saves the parsed data into a MongoDB document.

✅ Create a basic REST endpoint to get the previously saved data.

Must have:

✅ Basic error handling

✅ Basic README file

✅ Basic explaination of the work done

Extra points:

❌ unit testing

✅ Docker build

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Setup

To run this project you can use Yarn or Docker:

Yarn

yarn install
yarn start

Docker

docker-compose build
docker-compose up

TODO

• Error handling when RPC doesnt responds
• unittest

Original repository with commit history: [https://github.com/nsalto/cryptologic_challenge]