IPFS Overview & Ternoa IPFS Client

Overview

IPFS (Interplanetary File Systems) is one of the solutions we recommend to upload NFTs media and other associated metadata. Thus off-chain data are stored in a fully decentralized way and only the link to this metadata is stored on-chain as part of the NFT. This link is frequently a fingerprint called a cryptographic hash ID (e.g. Qmf5RHhnUjSCfCN9d1Ee6sUWxe3Eqvogw1cTsssrxAxtPn). IPFS files are accessible using those hashes.

On Ternoa NFTs are composed of two files: an asset file (e.g. image, video, music) and a metadata JSON file. The asset file hash is nested into the metadata file and both are stored on IPFS with their dedicated hashes.

Ternoa provides its own IPFS public nodes on different HTTP gateways based on the network environment:

• Mainnet: https://ipfs-mainnet.trnnfr.com

• Alphanet: https://ipfs-dev.trnnfr.com

Please note that a api-key is needed to store data on those gateways. Visit the next section and the IPFS Key Manager to obtain your API Key. After being generated, the key may need a few minutes to become effective for use with the Ternoa client.

Ternoa IPFS Client

An IPFS client is available on ternoa-js SDK to make IPFS upload simple with only one line of code.

Here is an example of uploading an image "shining.jpg" from the movie:

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

const main = async () => {
  const file = new File(
    [await fs.promises.readFile("shining.jpg")],
    "shining.jpg",
    {
      type: "image/jpg",
    }
  );

  const ipfsClient = new TernoaIPFS(new URL("IPFS_NODE_URL"), "IPFS_API_KEY");

  const nftMetadata = {
    title: "Shining, a nice movie",
    description: "This is (not) my first Ternoa's NFT",
  };

  const { Hash } = await ipfsClient.storeNFT(file, nftMetadata);
  console.log("The off-chain metadata hash is ", Hash);
};

First, the JPG image file named "shining.jpg" is read from the file system and wrapped in a specific File instance. The TernoaIPFS class is then used to create an IPFS client that connects to a specified IPFS node using a given API key. The metadata for the file is then defined in an object and passed to the storeNFT method of the client along with the File instance. The resulting Hash of the off-chain metadata is logged to the console.

The storeNFT method handles two IPFS uploads under the hood: a first one with the NFT media (e.g. the image) and a second one with the JSON metadata file, including the media's hash from the first upload response. This method also validates the metadata structure to ensure TIPs compatibility.

Additional methods are provided to handle secret NFTs, collections, and the marketplace. They worked in the same manner and were respectively: storeSecretNFT, storeCollection, and storeMarketplace.