BlockCal

Fully decentralized blockchain based calendar.

Specs

• Owner can create companies and assign rooms to them.
• Owner can create employees and assign them to companies.
• Employees can book a room for a given day slot.
• Employees can unbook their own booking.

Description

• This is my first ever Solidity smart contract, please don't be too picky on the data structure and the code, I still need to learn the best practices and this was a complete discovery.
• I went with a simple CRUD data structure and the same contract owns the data, there's no proxy to a data store only contract.
• To develop the contract itself I went with TDD using Hardhat and then deployed on the Ropsten testnet to interract with the UI I built.

How to run

• Clone the repository
• Create a .env and fill it according to .env.example
• Run yarn && yarn deploy copy the contract address and add it to web/.env
• Run cd web && yarn dev open your browser on http://localhost:3000 and voilà!

contracts/BlockCal.sol

• 0x8d48e5c896583c1aad7e40bec76c0d07e3fb75de (Ropsten)

Public Methods

• getCompanies() -> { id: string; name: string }[]
• getEmployees() -> { addr: string; name: string, companyId: string }[]
• getRooms() -> { id: string; companyId: string }[]
• getBookedSlots() -> { slotId: string; roomId: string; bookedBy: string; }[]

Owner methods

• addComapny(name: string)
• removeCompany(id: string)
• addEmployee(name: string, companyId: string)
• removeEmployee(addr: string)
• addRoom(name: string, companyId: string)
• removeRoom(id: string)

Employee methods

• bookSlot(roomId: string, slotId: string)
• unbookSlot(roomId: string, slotId: string)

Web UI

• The UI is built with React, ant.design and tailwindcss.
• For the deployment I went with fleek which is linked to the repository and auto-deploys new commits to IPFS network.

URLs

• ipfs://Qmdzg1NENbwdh67qQVc1wi7gp6MWfQuugJtuL8XsF5eVV7
• https://silent-math-4212.on.fleek.co/

Pages

• / -> connect to Metamask
• /admin -> administration interface to create companies, employees and rooms
• /calendar -> calendar interface to book and unbook slots for employees

Known issues

• When switching profile into Metamask the contract is not updated, you must refresh the page
• Reloading the page doesn't save the last connected user

Room for improvments

• Use multicall contract to fetch data for the UI
• The contract data and logic are stored in the same, this is a bad pattern. If you want to change your contrac logic you would have to migrate the data also.
  • Use external storage contract (https://github.com/fravoll/solidity-patterns/blob/master/docs/eternal_storage.md)
  • Use a proxy contract pattern (https://github.com/fravoll/solidity-patterns/blob/master/docs/proxy_delegate.md)