Final project - PapaPay - A web3 payment system between tutors and students

Deployed version url:

https://papapay.ordinar.io

How to run this project locally:

Prerequisites

Things that need to be installed/configured before running anything:

• Node.js >= v16
• Ganache UI
• Metamask extension installed and, to run local tests, a new Localhost network configured on RPC http://localhost:7545 (The default one is on port 8545)
• Clone this repo! :)

Contract deployment and testing

• Run npm install in project´s root directory. This will install Truffle, hdwallet, dotenv and OpenZeppelin ReentrancyGuard among others dependencies
• Run Ganache UI in port 7545 and network id 1337 Remember to add the truffle-config.js in Ganache´s truffle project. You can change the Network ID clicking in the configuration gear, then going to server and setting the Network ID to 1337 there
• To test the contract, edit ./contracts/PapaPay.sol, uncomment lines 293 to 310 (fetchCourse function), save changes, and from project´s root directory run run truffle migrate --network development --reset and then run truffle test
• To deploy the contract locally, edit ./contracts/PapaPay.sol and after re-commenting lines 293 to 310, run truffle migrate --network development --reset

Frontend deployment

• Go to client directory cd client
• If you want to use the previous locally deployed contract edit ./src/index.js and change line 22, state variable myChain from 0x3 (That´s Ropsten chainId) to 0x539 (Ganache´s 1337 chainId). Save and exit.
• Run npm install to install packages and dependencies
• To start the server run npm run start
• Open http://localhost:3000

Video link

https://www.loom.com/share/6b82735180be439b9df677f52f145d8b

Public Ethereum wallet for certification:

0x2fB6E185Dd70265D86298CAF775851262048e74C

Project description

This aims to solve the exchange of value when a tutor and a student engage in a one-on-one lesson, specially when both resides in different countries.

• Both parts meet to arrange an economic value and other requirements for the course wich is composed by one or more lessons.
• When they agree, the tutor creates a course and names it, declares the price of the entire course, the lessons quantity, a timelock wich allows the student to recover it´s assets after a period of time if the tutor doesn´t give the promised class, and, of course, the student address.
• The student then reviews that, and if agrees, approves the course, deducting the course value from the student´s wallet and storing it in the contract.
• When the student attends to a lesson, it signs a attendance counter, that allows the tutor to give the lesson (signing a init lesson counter) and therefore allowing the tutor to withdraw a fraction of the balance stored in the contract corresponding to the given lessons
• If a tutor doesn´t start a lesson after a student gives it´s attendance, or, the student never attend any lesson, the student can recover the balance left in the contract after the timelock period specified in the course creation

Example workflows

Tutor - Creating course

1. Enter PapaPay website
2. Select I´m a tutor
3. Clic on Create Course
4. Follow the on-screen instructions and fill all the fields (Use a student address under your control to test it later)
5. Clic on Create Course
6. See tx status under Create Course button

Student - Approving course and taking first lesson

1. Enter PapaPay website
2. Select I´m a student (Remember to use the student address declared earlier)
3. Read the on-screen sugestions, look out for your course and clic on Approve Course. You need to have sufficient ETH balance in your wallet for this to work
4. Then, attend your first lesson by clicking on Take Lesson
5. Always see tx status on bottom of the page

Teacher - Giving lesson and withdrawing

1. Enter PapaPay website
2. Select tutor, then select Give a Lesson
3. Look out for your course and clic on Give Lesson.
4. After a successful transaction, you can clic on Withdraw, if tx is successful, check your new balance in your wallet, and the new balance on the course
5. Always see tx status on bottom of the page

Student - Recovering balance

1. Enter PapaPay website
2. Select student (Remember to use the student address declared earlier)
3. Read the on-screen sugestions, look out for your course and clic on Recover Balance
4. If the timestamp hasn´t passed, metamask will throw a revert. After the timelock, there will be a successful transaction, you can check your new balance in your wallet, and the new balance on the course
5. Always see tx status on bottom of the page

Directory structure

• client: React frontend.
• contracts: Smart contracts.
• migrations: Migration files for deploying contracts.
• test: Unit tests.

Environment variables (not needed for running project locally)

ROPSTEN_INFURA_PROJECT_ID=
ROPSTEN_MNEMONIC=

TODO features

• Stop using block.timestamp and use Chainlink Keepers
• Improve gas consumption
• Improve React code, implement a place where students and tutors can pre-arrange a course

Thanks to

My friend Yamenk who helped me

Nana who always gives me good vibes and love

JYMS, Ni.ca and Moniko for the future

The beautiful team of Consensys, the new friends in the cohort, the mentors, and all the people who invest time in spreading the word of web3

zombo.com for everything else