Chainlink Truffle Box

Implementation of a Chainlink requesting contract.

Requirements

• NPM

Installation

Package installation should have occurred for you during the Truffle Box setup. However, if you add dependencies, you'll need to add them to the project by running:

npm install

Or

yarn install

Test

npm test

Deploy

If needed, edit the truffle-config.js config file to set the desired network to a different port. It assumes any network is running the RPC port on 8545.

npm run migrate:dev

For deploying to live networks, Truffle will use truffle-hdwallet-provider for your mnemonic and an RPC URL. Set your environment variables $RPC_URL and $MNEMONIC before running:

npm run migrate:live

Helper Scripts

There are 3 helper scripts provided with this box in the scripts directory:

• fund-contract.js
• request-data.js
• read-contract.js

They can be used by calling them from npx truffle exec, for example:

npx truffle exec scripts/fund-contract.js --network live

The CLI will output something similar to the following:

Using network 'live'.

Funding contract: 0x972DB80842Fdaf6015d80954949dBE0A1700705E
0xd81fcf7bfaf8660149041c823e843f0b2409137a1809a0319d26db9ceaeef650
Truffle v5.0.25 (core: 5.0.25)
Node v10.16.3

In the request-data.js script, example parameters are provided for you. You can change the oracle address, Job ID, and parameters based on the information available on our documentation.

npx truffle exec scripts/request-data.js --network live

This creates a request and will return the transaction ID, for example:

Using network 'live'.

Creating request on contract: 0x972DB80842Fdaf6015d80954949dBE0A1700705E
0x828f256109f22087b0804a4d1a5c25e8ce9e5ac4bbc777b5715f5f9e5b181a4b
Truffle v5.0.25 (core: 5.0.25)
Node v10.16.3

After creating a request on a live network, you will want to wait 3 blocks for the Chainlink node to respond. Then call the read-contract.js script to read the contract's state.

npx truffle exec scripts/read-contract.js --network live

Once the oracle has responded, you will receive a value similar to the one below:

Using network 'live'.

21568
Truffle v5.0.25 (core: 5.0.25)
Node v10.16.3

Project taglines:

1. What's LottoDAO?

LottoDAO is a decentralised lottery application based on the Ethereum blockchain and synchronised with Global major lottery platforms.

2. What's the difference between LottoDAO and other lottery platforms?

LottoDAO uses blockchain and Chainlink, the pivotal data is base on smart contracts, which is safe and won't be interfered by any third party.

3. What's the main advantage of LottoDAO?

With the advantage of utilising blockchain, LottoDAO is bringing off-chain data into on-chain. And it is more independent, as well as autonomous; also it allows lottery participants to purchase lotto entries in a secure way and makes the lottery transparent.

Inspiration

It was inspired by other lottery game

What it does

We want to enhance lottery game with off-chain lottery information such as rules.

How I built it

We built it with Solidity to create smart contract. Frontend running vue.js

Challenges I ran into

• Using Chainlink to get off-chain data to on-chain
• Using Chainlink to with alarm job and getting VRF random number

Accomplishments that I'm proud of

It's an on-chain lottery game with off-chain game information but secured by blockchain with transparent and non-changeable.

What I learned

Solidity, Chainlink, Vuejs

What's next for Lottery DAO

get traction and feedback from users.