P2P-Lending

About The Project

A decentralized, smart contract based platform for p2p-lending of any existing ERC20 Token on the Ethereum Blockchain with ETH as colletral. The open ecosystem of the p2p-lending platform has the potential to offer cheaper lending contracts than traditional centralized institutions, while also enabling people all over the world to profit from a fair and transparent portfolio of products.

Built With

• Node 13
• Truffle
• Ganache
• web3.js

Prerequisites

These are the requisites you need, in order to use the software and instructions, on how to install them.

NodeJS and NPM

curl -sL https://deb.nodesource.com/setup_12.x -o nodesource_setup.sh
sudo bash nodesource_setup.sh
sudo apt install nodejs

Ganache

Download it form this link https://truffleframework.com/ganache

Truffle

npm install truffle -g

Installation

Clone the repo

git clone <Current_URL>

Run Ganache on port 8545

Ganache -> Settings -> Server -> Port Number -> 8545

Go to smart_contract folder and Install dependencies

npm install

Compile Smart Contracts

truffle compile

Deploy Smart Contracts to local blockchain

npm run migrate:dev

Create Test Cases

Important : Run this only if you want to create new test cases.

Example :

truffle create test AskRequest

Run Test

npm run test

Backend

Update Smart Contract address in config/development.js (get this from the ganache gui or console output)

config.smartContractAddress.p2pToken

config.smartContractAddress.p2pPlatform

Go to api folder and Install dependencies

sudo npm install

Create Log folder

sudo mkdir -p /var/log/defi/
sudo chmod 777 -R /var/log/defi

Start backend

npm run start

Point to Testnets

Change below configuration in config/development.js

config.blockchain.url = {INFURA_URL} config.blockchain.chainId = {CHAIN_ID} (Ropsten - 3)

API Document

https://www.getpostman.com/collections/bab6a07226f6791e2eda

Deploying the Smart contract (Manually)

1. P2PToken.sol
2. RequestFactory.sol
3. Governance.sol
4. P2PPlatform.sol

Understand the Smart contract

1. Create Ask Request with collateral as ETH
2. Get created requests from API -> get Requests
3. Give Token approval from Lender to above address (same amount as asked)
4. Call Lend Function from Lender
5. Transfer some extra token to asker so that he can payback
6. Payback from lender, Colletral will come back
7. Collect Collateral if not paid before deadline
8. Cancel Request before Lender pay
9. Change is Valid from upVote from Governance Contract

Deploy on Ropsten Network

HINT (Session 2) Deploy contract on ethereum ropsten network

1. Set your Infura Key(https://infura.io/) and Mnemonic as below (Use your existing seed or create new and transfer some ether to it)
2. Update "from" address in truffle-config.js which have funds

export INFURA_API_KEY="asdasd"
export MNEMONIC="asd asd ...."

Services

Block Crawler (Sample)

To capture all blockchain transaction

cd api
node script/blockCrawler.js

Upgradable Smart Contract Demo

Move to upgradable_smart_contract_demo folder.

Install Open Zepplelin Cli

npm install -g @openzeppelin/cli
oz --version

## (Optional) Initialize Openzeppelin Env (one time only)

This is already done in project. However if you want to do it from scratch run below commands :

npm init -y
oz init
npm install @openzeppelin/upgrades --save

Compile Contract

oz compile

Deploy Contract

Important : Delete .openzeppelin/dev-* file before starting from scratch.

oz create

Interact with Contract

oz call
oz send-tx

Upgrade Contract

Change some code and run below

oz upgrade

Understand the Defi app architecture

1. Smart contract creation
2. Smart contract deployment (truffle)
3. Get the JSON builds (ABI files)
4. Create your blockchain connection (web3)
5. Create your smart contract object (contractObj -> ABI and Smart Contract Address)
6. Interact with the contract
   1. Read : .call()
   2. Write : RawTransaction(APP work -> FE/BE) -> SignedTransaction(Wallet like metamask) -> Broadcast(Wallet like metamask)

Troubleshoot

Failed at the scrypt@6.0.3 install script.

sudo npm install github:barrysteyn/node-scrypt#fb60a8d3c158fe115a624b5ffa7480f3a24b03fb
OR
sudo npm i web3

Cannot read property 'addFunction' of undefined

sudo npm update truffle

Invalid Sender Error on Ropsten network in API

web3/web3.js#2915

sudo npm i ethereumjs-tx@1.3.7

Code Changes in signTransaction()

let tx = new Tx(rawTxObject); for Version 1.3.7