Follow contract guide

Using the FollowRegister contract deployed by Relation Protocol, we can create a Follow contract for a user. The Follow contract can follow and unfollow someone. Both the FollowRegister and Follow contracts have implemented the contract interface defined by the Contract Standard.

Construct a Contract object

The contract addresses and abi files of the FollowRegister and FollowWithSign contract, and the abi file of the Follow contract, can be accessed via Relation Protocol list of resources. The address of the Follow contract can be accessed via FollowRegister, with each address having its own Follow contract.

Construct a FollowRegisterContract object with "ethers":

import { ethers, providers } from 'ethers'

const getFollowRegisterContractInstance = () => {
    // FollowRegister contract address
    const contractAddress = '0xab8Dde275F3d2508c578C5bbDf43E81964BF18A4'
    const provider = new providers.Web3Provider(window.ethereum)
    const signer = provider.getSigner()
    const contract = new ethers.Contract(contractAddress, followRegisterAbi, signer)
    return contract
}

const getFollowWithSignContractInstance = () => {
    const contractAddress = '0xAC0f863b66173E69b1C57Fec5e31c01c7C6959B7'
    const provider = new providers.Web3Provider(window.ethereum)
    const signer = provider.getSigner()
    const contract = new ethers.Contract(contractAddress, followWithSignAbi, signer)
    return contract
}

Call the methods of a contract

FollowRegister

1. Deploy the Follow contract:

const followRegisterContract = getFollowRegisterContractInstance()
const accounts = await ethereum.request({ method: 'eth_requestAccounts' })
await (
    await followRegisterContract.deployFollowContract(accounts[0])
).wait()

1. Query the Follow contract of a user, and construct a Contract object.

Once a Follow contract is deployed by a user, the address of the contract can be acquired via the user's address.

const addr = '0x000...';
const followRegisterContract = getFollowRegisterContractInstance()
const followContractAddress = await followRegisterContract.ownedFollowContract(addr);

const getFollowContractInstance = (followContractAddress) => {
    const provider = new providers.Web3Provider(window.ethereum)
    const signer = provider.getSigner()
    const contract = new ethers.Contract(followContractAddress, followAbi, signer)
    return contract
}

Follow

1. Follow

To follow a certain address, a user will call the address's Follow contract:

const addr = '0x000...';
const followRegisterContract = getFollowRegisterContractInstance()
const followContractAddress = await followRegisterContract.ownedFollowContract(addr);
const followContract = getFollowContractInstance(followContractAddress)

await (
    await followContract.follow()
).wait()

1. Unfollow

const addr = '0x000...';
const followRegisterContract = getFollowRegisterContractInstance()
const followContractAddress = await followRegisterContract.ownedFollowContract(addr);
const followContract = getFollowContractInstance(followContractAddress)

await (
    await followContract.unfollow()
).wait()

1. A user's list of followers

We can get the list of followers of a user by querying the token owners of the user's Follow contract.

const addr = '0x000...';
const followRegisterContract = getFollowRegisterContractInstance()
const followContractAddress = await followRegisterContract.ownedFollowContract(addr);
const followContract = getFollowContractInstance(followContractAddress)

const numOfFollower = await followContract.totalSupply();
var followerList = [];
for(var i = 0; i < numOfFollower;i++){
    const tokenId = await followContract.tokenByIndex(i);
    const follower = await followContract.ownerOf(tokenId);
    followerList.push(follower);
}

1. Follow(Gas fee can be paid by someone else)

A user signs against the data and constructs it into a parameter to be posted on the blockchain. Any address can initiate a transaction with this parameter, with the gas paid by said address.

import { Bytes } from '@ethersproject/bytes'

const accounts = await ethereum.request({ method: 'eth_requestAccounts' })

const followRegisterContract = getFollowRegisterContractInstance()
const followContractAddress = await followRegisterContract.ownedFollowContract(accounts[0]);
const followContract = getFollowContractInstance(followContractAddress)
const followWithsignContract = getFollowWithSignContractInstance(followContractAddress)

const name = await followWithsignContract.name();
const nonce = await followWithsignContract.nonces(accounts[0]);
const deadline = Date.parse(new Date()) / 1000 + 100;
const sign = await getSign(await buildFollowParams(name, followWithsignContract.toLowerCase(),followContractAddress.toLowerCase(), parseInt(nonce), deadline), accounts[0]);
//The parameter will be passed to the method "followWithSign"
var param =
    {"sig": {"v": sign.v, "r": sign.r, "s": sign.s, "deadline": deadline},
        "target": followContractAddress,
        "addr": accounts[0]
    }
//In reality, this method will be called by the address paying the gas fee.
await followWithsignContract.connect(accounts[1]).followWithSign(param);


async function getSign(msgParams, signerAddress) {
    const params = [signerAddress, msgParams];
    const trace = await hre.network.provider.send(
        "eth_signTypedData_v4", params);
    return Bytes.splitSignature(trace);
}

async function getChainId() {
    return await ethereum.request({
        method: 'eth_chainId',
    });
}
async function buildFollowParams(name, contractAddress, followContractAddress, nonce, deadline) {
    return {
        domain: {
            chainId: await getChainId(),
            name: name,
            verifyingContract: contractAddress,
            version: '1',
        },

        // Defining the message signing data content.
        message: {
            target: followContractAddress,
            nonce: nonce,
            deadline: deadline,
        },
        // Refers to the keys of the *types* object below.
        primaryType: 'FollowWithSign',
        types: {
            EIP712Domain: [
                {name: 'name', type: 'string'},
                {name: 'version', type: 'string'},
                {name: 'chainId', type: 'uint256'},
                {name: 'verifyingContract', type: 'address'},
            ],
            FollowWithSign: [
                {name: 'target', type: 'address'},
                {name: 'nonce', type: 'uint256'},
                {name: 'deadline', type: 'uint256'},
            ],
        },
    };
}

1. Unfollow(Gas fee can be paid by someone else)

A user signs against the data and constructs it into a parameter to be posted on the blockchain. Any address can initiate a transaction with this parameter, with the gas paid by said address.

import { Bytes } from '@ethersproject/bytes'

const accounts = await ethereum.request({ method: 'eth_requestAccounts' })

const followRegisterContract = getFollowRegisterContractInstance()
const followContractAddress = await followRegisterContract.ownedFollowContract(accounts[0]);
const followContract = getFollowContractInstance(followContractAddress)
const followWithSignContract = getFollowWithSignContractInstance(followContractAddress)

const name = await followWithSignContract.name();
const nonce = await followWithSignContract.nonces(accounts[0]);
const deadline = Date.parse(new Date()) / 1000 + 100;
const sign = await getSign(await buildUnFollowParams(name, followWithSignContract.address.toLowerCase(), followContractAddress.toLowerCase(),parseInt(nonce), deadline), accounts[0]);
//The parameter will be passed to the method "followWithSign"
var param =
    {"sig": {"v": sign.v, "r": sign.r, "s": sign.s, "deadline": deadline},
    "target": followContractAddress,
    "addr": accounts[0]
    }
//In reality, this method will be called by the address paying the gas fee.
await followWithSignContract.connect(accounts[1]).unfollowWithSign(param);


async function getSign(msgParams, signerAddress) {
    const params = [signerAddress, msgParams];
    const trace = await hre.network.provider.send(
        "eth_signTypedData_v4", params);
    return Bytes.splitSignature(trace);
}

async function getChainId() {
    return await ethereum.request({
        method: 'eth_chainId',
    });
}

async function buildUnFollowParams(name, contractAddress, followContractAddress,nonce, deadline) {
    return {
        domain: {
            chainId: await getChainId(),
            name: name,
            verifyingContract: contractAddress,
            version: '1',
        },

        // Defining the message signing data content.
        message: {
            target: followContractAddress,
            nonce: nonce,
            deadline: deadline,
        },
        // Refers to the keys of the *types* object below.
        primaryType: 'UnFollowWithSign',
        types: {
            EIP712Domain: [
                {name: 'name', type: 'string'},
                {name: 'version', type: 'string'},
                {name: 'chainId', type: 'uint256'},
                {name: 'verifyingContract', type: 'address'},
            ],
            UnFollowWithSign: [
                {name: 'target', type: 'address'},
                {name: 'nonce', type: 'uint256'},
                {name: 'deadline', type: 'uint256'},
            ],
        },
    };
}