Blockchain JO 2024

This school project is the blockchain part of a ticket manager for JO 2024. There is a bonus web application to show how to call your blockchain contract.

It's a good minimalist example of what can be done with solidity and web3js.

Prerequisites

First you need to have some packages installed:

• npm (needed for solidity dependencies)

• yarn (optional if you want to use yarn instead of npm to install packages of app)

• expo (needed to launch the app)

Blockchain packages installation

Ganache (development)

Ganache is needed to create a private blockchain. It allows you to deploy your contracts in a local environment.

Install it :

npm install ganache ganache-cli ganache-core --global

Truffle

Truffle is needed to build your contracts and deploy them on any blockchain.

Install it :

npm install truffle --global

Usage

Private blockchain deployment

First, you need to launch a private blockchain locally.

ganache-cli

something like this is displayed :

⚠️ don't stop the command or close this terminal. Open a new one for other commands.

Contracts build and deployment

Then, you can modify the file truffle-config.js with your own configurations.

Deploy your contract : (You don't need to build your contracts, this command do it for you)

truffle deploy --network [network_name]
# truffle deploy --network development

the network_name parameter is the name of your network in the truffle-config.js, in the networks section. (for example development)

You will get something like that :

⚠️ you can see the contract address, keep it somewhere.

Web application deployment

First, you need to get the built contract informations:

cp build/contracts/TicketFactory.json app/utils/TicketFactory.json

Modify the TicketFactoryAddress variable in the file app/App.js. (this value is the contract address given by the truffle command)

Go to app folder and install dependencies

cd app

expo install
# OR yarn install
# OR npm install

Start the application

expo start
# OR yarn start
# OR npm start

You can now go to your application at the url given by expo