Links

The Links extension represents a generic way to point to off-chain data. It consists of a list of link pairs, each of which contains a name and a uri. This can be used to point to any additional off-chain data or resources.

Field	Description
values[0..n]	List of Link objects.
Each Link object is represented by:
name	Name of the link.
uri	URI value.

Creating Links

The Links extension can be created using either the allocate, create or update instruction.

JavaScript

import { allocate, links } from '@nifty-oss/asset';

await allocate(umi, {
  asset,
  payer,
  extension: links([
    { name: 'homepage', value: 'https://nifty-oss.org' },
    { name: 'twitter', value: 'https://twitter.com/nifty_oss' }
  ]),
}).sendAndConfirm(umi);

Rust

use nifty_asset::{
  extensions::{Attributes, LinksBuilder, ExtensionBuilder},
  instructions::AllocateBuilder,
  types::{ExtensionInput, ExtensionType},
};

let mut links = LinksBuilder::default();
links.add("homepage", "https://nifty-oss.org");
links.add("twitter", "https://twitter.com/nifty_oss");

let ix = AllocateBuilder::new()
  .asset(asset.pubkey())
  .payer(Some(payer.pubkey()))
  .system_program(Some(system_program::id()))
  .extension(ExtensionInput {
    extension_type: ExtensionType::Links,
    length: links.len() as u32,
    data: Some(links),
})
.instruction();

Rust (on-chain)

use nifty_asset::{
  extensions::{Attributes, AllocateCpiBuilder, ExtensionBuilder},
  instructions::AllocateBuilder,
  types::{ExtensionInput, ExtensionType},
};

let mut links = LinksBuilder::default();
links.add("homepage", "https://nifty-oss.org");
links.add("twitter", "https://twitter.com/nifty_oss");

AllocateCpiBuilder::new(ctx.accounts.nifty_asset_program)
  .asset(ctx.accounts.group)
  .payer(Some(ctx.accounts.payer))
  .system_program(Some(ctx.accounts.system_program))
  .extension(ExtensionInput {
    extension_type: ExtensionType::Attributes,
    length: links.len() as u32,
    data: Some(links),
})
.invoke();

Fetching Links

Given an asset account, it is possible to retrieve the links of an asset. Note that not all assets might have the extension, therefore it is necessary to assert if the extension was found.

JavaScript

import {
  ExtensionType,
  fetchAsset,
  getExtension
} from '@nifty-oss/asset';

const asset = await fetchAsset(umi, address);
const links = getExtension(asset, ExtensionType.Links);

if (links) {
    links.values.forEach(({ name, uri }) => {
        console.log(name + '=' + uri);
    });
}

Rust

use nifty_asset::{
  extensions::Links,
  state::Asset,
};

let account = get_account(address)
  .await
  .unwrap();
let account_data = account.data.as_ref();

if let Some(links) = Asset::get::<Links>(account_data) {
  println!("links: {:?}", links);
}

Rust (on-chain)

use nifty_asset::{
  extensions::Links,
  state::Asset,
};

let data = (*ctx.accounts.asset.data).borrow();

if let Some(links) = Asset::get::<Links>(&data) {
  msg!("links: {:?}", links);
}