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Edit Token Metadata

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

To edit an LSP7 Digital Asset metadata, 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 Getting Started or Create LSP7 Token guides before you continue.

Setup​

First, you have to prepare all imports and constants to send the transaction. In this example, we will update the metadata of a previously deployed LSP7 token using our default Hardhat setup.

scripts/attachAssetMetadataAsUP.ts
import { ethers } from 'hardhat';
import * as dotenv from 'dotenv';

import LSP7Artifact from '@lukso/lsp-smart-contracts/artifacts/LSP7DigitalAsset.json';
import UniversalProfileArtifact from '@lukso/lsp-smart-contracts/artifacts/LSP0ERC725Account.json';

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

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

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

// Instantiate asset
const token = await ethers.Contract(myAssetAddress, LSP7Artifact.abi, signer);

// Instantiate executing Universal Profile
const universalProfile = new ethers.Contract(
  process.env.UP_ADDR,
  UniversalProfileArtifact.abi,
  signer,
);

Execute the metadata update​

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

In order to update the metadata using your Universal Profile, the setData() function of the contract can not be called directly. Instead, you have to generate the payload of the transaction and execute it by calling the execute() function of the Universal Profile.

scripts/attachAssetMetadataAsUP.ts
// ...

// Create the transaction payload for the contract call
const setDataPayload = token.interface.encodeFunctionData('setData', [
  encodedLSP4Metadata.keys[0],
  encodedLSP4Metadata.values[0],
]);

// Update the ERC725Y storage of the LSP4 metadata
const tx = await universalProfile.execute(
  0, // Operation type: CALL
  myAssetAddress, // Target: asset address
  0, // Value is empty
  setDataPayload, // bytecode to be executed
);

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