Update a Capsule NFT content


Before getting started, make sure you have the following ready:

  1. Create a Ternoa account with Alphanet CAPS

  2. Install and set up your editor of choice (we will use Visual Studio Code [VSC] in this tutorial)

  3. Install NodeJS v.14+ & NPM

Update a Capsule NFT using Ternoa-JS: Add a new asset to the Capsule

If you want to update the content of a Capsule NFT on the Ternoa chain by adding a new asset, follow these steps:

  • Retrieve the capsule off-chain data CID hash using Ternoa Indexer.

  • Prepare new asset: encryption and storage on IPFS.

  • Prepare new capsule metadata with the new encrypted media added to the content array.

  • Update the capsule off-chain data CID hash on-chain.

Step 1: Retrieve the capsule off-chain data CID hash using Ternoa Indexer

Ternoa indexer is a record of the Ternoa Chain data. You can query data for some specific entities (NFT, Collection, Marketplace(...)) using GraphQL.

You first need to prepare a stringified query to get NFT data from a specific Capsule NFT id.

  nftEntity(id: "NFT_ID") {

The data we will use in step 2 is capsuleOffchainData the IPFS CID hash of the Capsule NFT (e.g. "QmNM7fDadTjoLKqMi8i4Lyru4FUiKyQYpRmSoXnDjtgm6N").

Learn more about the NFTEntity and how to fetch data from the Ternoa Indexer here.

Step 2: Prepare new asset - encryption and stored on IPFS

Before adding a new asset to an existing Capsule NFT you have to encrypt the asset and store it on IPFS. Ternoa-JS provides you with an encryptFile helper to do so. It uses a specified public PGP key to encrypt the asset. You can generate a PGP key pair using the generatePGPKeys helper from Ternoa-JS. To store the encrypted asset on IPFS you can use the storeFile method from the TernoaIPFS client. Here is an example of a code snippet:

import fs from "fs";
import { encryptFile, TernoaIPFS, File } from "ternoa-js";

const prepareAsset = async () => {
  try {
    const IPFS_NODE_URL = "IPFS_NODE_URL"; // The IPFS node used.
    const IPFS_API_KEY = "IPFS_API_KEY"; // The IPFS node API KEY if required.
    const PUBLIC_PGP_KEY = "PUBLIC_PGP_KEY"; // The public PGP key used to encrypt the new asset to add.

    const newAsset = new File(
      [await fs.promises.readFile("FILE_NAME_1")],
        type: "FILE_TYPE_1",

    const newEncryptedAsset = await encryptFile(newAsset, "PUBLIC_PGP_KEY");

    const ipfsClient = new TernoaIPFS(new URL(IPFS_NODE_URL), IPFS_API_KEY);
    const { Hash: ASSET_HASH, Size: ASSET_SIZE } = await ipfsClient.storeFile(

    // Encrypted asset ASSET_HASH & ASSET_SIZE will be used in step 3
    // ...
  } catch (e) {

Step 3: Prepare new capsule metadata with the new encrypted media added to the content array

A Ternoa Capsule NFT comprises additional files: several asset files (such as an image, video, or music file) and a metadata JSON file for the capsule. To ensure maximum security and exclusivity, asset files must be encrypted, and the encrypted files are nested within the metadata file. Both files are stored on IPFS (Interplanetary File Systems) with unique hashes dedicated to each file.

import fs from "fs";
import { encryptFile, TernoaIPFS, File } from "ternoa-js";

const updateCapsuleMetadata = async () => {
  try {
    // ...
    // fetching CAPSULE_OFFCHAIN_DATA in step 1
    // Encrypted asset ASSET_HASH & ASSET_SIZE retrieved in step 2

    const res = (await ipfsClient.getFile(
    )) as NftMetadataType;

    const newAsset = {
      hash: ASSET_HASH,
      size: Number(ASSET_SIZE),
      type: "text/plain",

    const capsuleMetadata = {
      properties: {
        encrypted_media: [...encrypted_media, newAsset],

    const capsuleNFTMetadataBlob = new Blob([JSON.stringify(capsuleMetadata)], {
      type: "application/json",
    const capsuleNFTMetadataFile = new File(
      "Capsule NFT metadata"
    const { Hash: NEW_CAPSULE_OFFCHAIN_DATA } = await TernoaIPFS.storeFile(

    // NEW_CAPSULE_OFFCHAIN_DATA will be used in step 4
    // ...
  } catch (e) {

This function retrieves first the current capsule metadata from IPFS using the getFile method from the TernoaIPFS client. Next, a new asset is added to the encrypted_media array within the metadata object using object and array spreading. The new metadata is stored as a JSON-formatted Blob object then as a File instance. The updated metadata JSON File is then stored on IPFS using the storeFile method from the TernoaIPFS client, which returns a hash value for the new metadata object. This hash is saved for use in the final Step 4. If any errors occur during this process, they are logged to the console using "console.error".

Step 4: Update the capsule off-chain data CID hash on-chain

import {
} from "ternoa-js";

const setCapsuleMetadata = async () => {
  try {
    // ...
    // fetching NEW_CAPSULE_OFFCHAIN_DATA in step 3

    const SEED = "//TernoaTestAccount"; // The Capsule NFT owner seed phrase.
    const keyring = await getKeyringFromSeed(SEED);

    await setCapsuleOffchaindata(
  } catch (e) {

This program uses the setCapsuleOffchaindata function to update the off-chain data associated with the NFT capsule. This function takes several parameters including the NFT ID, the new off-chain data hash value retrieved in Step 3, the keyring associated with the capsule owner, and a WaitUntil block inclusion option. If any errors occur during this process, they will be logged to the console using "console.error()".

Use your own account by updating the //TernoaTestAccount with your account seed when retrieving the keyring from the example below.


If you face any trouble, feel free to reach out to our community engineers in our Discord.

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