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Set NFT Metadata

The function setDataBatchForTokenIds(...) can be used to set multiple data key-value pairs at once for one or multiple tokenIds.

Examples​

Set multiple metadata at once on the same tokenId​

To set for instance 3 x data key-value pairs for the same tokenId, the parameters of setDataBatchForTokenIds(bytes32[],bytes32[],bytes[]) can be used as follow:

// SPDX-License-Identifier: Apache-2.0
pragma solidity ^0.8.12;

import {
    ILSP8IdentifiableDigitalAsset as ILSP8
} from "@lukso/lsp-smart-contracts/contracts/LSP8IdentifiableDigitalAsset/ILSP8IdentifiableDigitalAsset.sol";
import {
    _LSP4_METADATA_KEY
} from "@lukso/lsp-smart-contracts/contracts/LSP4DigitalAssetMetadata/LSP4Constants.sol";

bytes32 constant _NFT_ICON_DATA_KEY = keccak256("NFTIcon");
bytes32 constant _NFT_MARKET_PLACE_URLS__DATA_KEY = keccak256("NFTMarketplaceURLs");

bytes32 constant _TOKEN_ID_TO_SET = 0xcafecafecafecafecafecafecafecafecafecafecafecafecafecafecafecafe;

function setMultipleDataForSingleTokenId(
    ILSP8 lsp8Contract,
    bytes memory lsp4MetadataValue,
    bytes memory nftIconValue,
    bytes memory nftMarketPlaceURLsValue
) {
    bytes32[] memory tokenIdsToUpdate = new bytes32[](3);
    bytes32[] memory dataKeysToSet = new bytes32[](3);
    bytes[] memory dataValuesToSet = new bytes[](3);

    // we are setting 3 x data key-value pairs for the same tokenid
    tokenIdsToUpdate[0] = _TOKEN_ID_TO_SET;
    tokenIdsToUpdate[1] = _TOKEN_ID_TO_SET;
    tokenIdsToUpdate[2] = _TOKEN_ID_TO_SET;

    dataKeysToSet[0] = _LSP4_METADATA_KEY;
    dataKeysToSet[1] = _NFT_ICON_DATA_KEY;
    dataKeysToSet[2] = _NFT_MARKET_PLACE_URLS__DATA_KEY;

    dataValuesToSet[0] = lsp4MetadataValue;
    dataValuesToSet[1] = nftIconValue;
    dataValuesToSet[2] = nftMarketPlaceURLsValue;

    lsp8Contract.setDataBatchForTokenIds(
        tokenIdsToUpdate,
        dataKeysToSet,
        dataValuesToSet
    );
}

Set metadata on different tokenIds​

To set for instance the same data key-value pair (e.g: LSP4Metadata) for 3 x different tokenIds, the parameters of setDataBatchForTokenIds(bytes32[],bytes32[],bytes[]) can be used as follow:

// SPDX-License-Identifier: Apache-2.0
pragma solidity ^0.8.12;

import {
    ILSP8IdentifiableDigitalAsset as ILSP8
} from "@lukso/lsp-smart-contracts/contracts/LSP8IdentifiableDigitalAsset/ILSP8IdentifiableDigitalAsset.sol";
import {
    _LSP4_METADATA_KEY
} from "@lukso/lsp-smart-contracts/contracts/LSP4DigitalAssetMetadata/LSP4Constants.sol";

bytes32 constant _FIRST_TOKEN_ID_TO_SET = 0xcafecafecafecafecafecafecafecafecafecafecafecafecafecafecafecafe;
bytes32 constant _SECOND_TOKEN_ID_TO_SET = 0xbeefbeefbeefbeefbeefbeefbeefbeefbeefbeefbeefbeefbeefbeefbeefbeef;
bytes32 constant _THIRD_TOKEN_ID_TO_SET = 0xf00df00df00df00df00df00df00df00df00df00df00df00df00df00df00df00d;

function setMultipleDataForSingleTokenId(
    ILSP8 lsp8Contract,
    bytes memory firstTokenIdLsp4MetadataValue,
    bytes memory secondTokenIdLsp4MetadataValue,
    bytes memory thirdTokenIdLsp4MetadataValue
) {
    bytes32[] memory tokenIdsToUpdate = new bytes32[](3);
    bytes32[] memory dataKeysToSet = new bytes32[](3);
    bytes[] memory dataValuesToSet = new bytes[](3);

    tokenIdsToUpdate[0] = _FIRST_TOKEN_ID_TO_SET;
    tokenIdsToUpdate[1] = _SECOND_TOKEN_ID_TO_SET;
    tokenIdsToUpdate[2] = _THIRD_TOKEN_ID_TO_SET;

    // we are setting the metadata for 3 x different tokenIds
    dataKeysToSet[0] = _LSP4_METADATA_KEY;
    dataKeysToSet[1] = _LSP4_METADATA_KEY;
    dataKeysToSet[2] = _LSP4_METADATA_KEY;

    dataValuesToSet[0] = firstTokenIdLsp4MetadataValue;
    dataValuesToSet[1] = secondTokenIdLsp4MetadataValue;
    dataValuesToSet[2] = thirdTokenIdLsp4MetadataValue;

    lsp8Contract.setDataBatchForTokenIds(
        tokenIdsToUpdate,
        dataKeysToSet,
        dataValuesToSet
    );
}

Check if the metadata of a specific NFT (tokenId) has changed​

Since LSP8 uses ERC725Y under the hood, the URI pointing to the metadata of a specific tokenId can be changed inside the ERC725Y storage of the LSP8 contract.

We have seen in the previous section how to set metadata for one or multiple tokenIds.

The two functions setDataForTokenId(...) and setDataBatchForTokenIds(...) emit a TokenIdDataChanged event. You can listen for this event in the LSP8 contract from your dApp, filtering for the LSP4Metadata data key to check if the metadata of a tokenId has been changed. You can do so by filtering the first parameter with the tokenId and the second parameter with the bytes32 value of the LSP4Metadata data key.