Set LSP7 Token Metadata

👇🏻 Hands on 📽️ ethers.js workshop video for the Oxford Blockchain Society from March 2024.

In this guide, you will learn how to edit the LSP4Metadata of an LSP7 Digital Asset. You will need to:

1. get your assets ready (images, videos, etc.) and create a metadata JSON file
2. upload these files using a preferred storage provider
3. generate an encoded value based on the URL to the metadata JSON file
4. write that value in the smart contract key-value store

For steps 1 to 3, there is a dedicated Asset Preparation Guide. Once your assets are uploaded and the URL to your metadata JSON file is ready and encoded, come back here.

Show encoded LSP4 Object

const encodedLSP4Metadata = {
  keys: ['0x9afb95cacc9f95858ec44aa8c3b685511002e30ae54415823f406128b85b238e'],
  values: [
    '0x00006f357c6a0020610be5a5ebf25a8323ed5a9d8735f78aaf97c7e3529da7249f17e1b4129636f3697066733a2f2f516d5154716865424c5a466e5155787535524473387441394a746b78665a714d42636d47643973756b587877526d',
  ],
};

Code repository

You can find all the contracts, sample metadata, and scripts of the guide within our lukso-playground repository.

Contract Deployment

If you want to learn more about the contract deployment itself, please have a look at the Create LSP7 Token guides before you continue.

Setup

First, prepare the encoded metadata and connect to your token contract.

ethers

set-token-metadata-ethers.js

import { ethers } from 'ethers';
import LSP7Artifact from '@lukso/lsp-smart-contracts/artifacts/LSP7DigitalAsset.json';

// As generated in the Asset Preparation guide
const encodedLSP4Metadata = {
  keys: ['0x9afb95cacc9f95858ec44aa8c3b685511002e30ae54415823f406128b85b238e'],
  values: [
    '0x00006f357c6a0020610be5a5ebf25a8323ed5a9d8735f78aaf97c7e3529da7249f17e1b4129636f3697066733a2f2f516d5154716865424c5a466e5155787535524473387441394a746b78665a714d42636d47643973756b587877526d',
  ],
};

// Connect via the UP Browser Extension
const provider = new ethers.BrowserProvider(window.lukso);
await provider.send('eth_requestAccounts', []);
const signer = await provider.getSigner();

const myAssetAddress = '0x...';

// Instantiate the token contract
const token = new ethers.Contract(myAssetAddress, LSP7Artifact.abi, signer);

web3

set-token-metadata-web3.js

import Web3 from 'web3';
import LSP7Artifact from '@lukso/lsp-smart-contracts/artifacts/LSP7DigitalAsset.json';

// As generated in the Asset Preparation guide
const encodedLSP4Metadata = {
  keys: ['0x9afb95cacc9f95858ec44aa8c3b685511002e30ae54415823f406128b85b238e'],
  values: [
    '0x00006f357c6a0020610be5a5ebf25a8323ed5a9d8735f78aaf97c7e3529da7249f17e1b4129636f3697066733a2f2f516d5154716865424c5a466e5155787535524473387441394a746b78665a714d42636d47643973756b587877526d',
  ],
};

// Connect via the UP Browser Extension
const web3 = new Web3(window.lukso);
await web3.eth.requestAccounts();
const accounts = await web3.eth.getAccounts();

const myAssetAddress = '0x...';

// Instantiate the token contract
const token = new web3.eth.Contract(LSP7Artifact.abi, myAssetAddress);

Hardhat

scripts/attachAssetMetadataAsEOA.ts

import { ethers } from 'hardhat';
import LSP7Artifact from '@lukso/lsp-smart-contracts/artifacts/LSP7DigitalAsset.json';
import * as dotenv from 'dotenv';

// Load the environment variables
dotenv.config();

// As generated in the Asset Preparation guide
const encodedLSP4Metadata = {
  keys: ['0x9afb95cacc9f95858ec44aa8c3b685511002e30ae54415823f406128b85b238e'],
  values: [
    '0x00006f357c6a0020610be5a5ebf25a8323ed5a9d8735f78aaf97c7e3529da7249f17e1b4129636f3697066733a2f2f516d5154716865424c5a466e5155787535524473387441394a746b78665a714d42636d47643973756b587877526d',
  ],
};

const [signer] = await ethers.getSigners();
const myAssetAddress = '0x...';

// Instantiate the token contract
const token = new ethers.Contract(myAssetAddress, LSP7Artifact.abi, signer);

Set data on token

Once you have the data key and value (with the encoded VerifiableURI in it), call the setData(bytes32,bytes) function on the Token contract.

ethers

set-token-metadata-ethers.js

// Update the ERC725Y storage of the LSP4 metadata
const tx = await token.setData(
  encodedLSP4Metadata.keys[0],
  encodedLSP4Metadata.values[0],
);

// Wait for the transaction to be included in a block
const receipt = await tx.wait();
console.log('✅ Token metadata updated:', receipt.hash);

web3

set-token-metadata-web3.js

// Update the ERC725Y storage of the LSP4 metadata
const receipt = await token.methods
  .setData(encodedLSP4Metadata.keys[0], encodedLSP4Metadata.values[0])
  .send({ from: accounts[0] });

console.log('✅ Token metadata updated:', receipt.transactionHash);

Hardhat

scripts/attachAssetMetadataAsEOA.ts

// Update the ERC725Y storage of the LSP4 metadata
const tx = await token.setData(
  encodedLSP4Metadata.keys[0],
  encodedLSP4Metadata.values[0],
);

// Wait for the transaction to be included in a block
const receipt = await tx.wait();
console.log('✅ Token metadata updated:', receipt);

Run the script:

npx hardhat --network luksoTestnet run scripts/attachAssetMetadataAsEOA.ts

Setting multiple data keys at once

If you need to update multiple metadata keys simultaneously, use setDataBatch(bytes32[],bytes[]):

ethers

const tx = await token.setDataBatch(
  encodedLSP4Metadata.keys,
  encodedLSP4Metadata.values,
);
await tx.wait();

web3

await token.methods
  .setDataBatch(encodedLSP4Metadata.keys, encodedLSP4Metadata.values)
  .send({ from: accounts[0] });

Hardhat

const tx = await token.setDataBatch(
  encodedLSP4Metadata.keys,
  encodedLSP4Metadata.values,
);
await tx.wait();