Bubblegum

How do I find the arguments needed for operations such as transfer, delegate, burn, etc?

Whenever we use an instruction that ends up replacing a leaf in the Bubblegum Tree — such as transfer, delegate, burn, etc. — the program requires a bunch of parameters that are used to ensure the current leaf is valid and can be updated. This is because the data of Compressed NFTs is not available inside on-chain accounts and therefore additional parameters such as the Proof, the Leaf Index, the Nonce and more are required for the program to fill the pieces.

All of that information can be retrieved from the Metaplex DAS API using both the getAsset and the getAssetProof RPC methods. However, the RPC responses from these methods and the parameters expected by the instructions are not exactly the same and parsing from one to the other is not trivial.

Fortunately, our SDKs provide a helper method that will do all the heavy lifting for us, as we can see in the code examples below. It accepts the Asset ID of the Compressed NFT and returns a bunch of parameters that can be directly injected into instructions that replace the leaf — such as burn, transfer, update, etc.

That being said, if you ever needed to do that parsing yourself, here is a quick breakdown of the parameters expected by the instructions and how to retrieve them from the Metaplex DAS API. Here we will assume the result of the getAsset and getAssetProof RPC methods are accessible via the rpcAsset and rpcAssetProof variables respectively.

Leaf Owner: Accessible via rpcAsset.ownership.owner.
Leaf Delegate: Accessible via rpcAsset.ownership.delegate and should default to rpcAsset.ownership.owner when null.
Merkle Tree: Accessible via rpcAsset.compression.tree or rpcAssetProof.tree_id.
Root: Accessible via rpcAssetProof.root.
Data Hash: Accessible via rpcAsset.compression.data_hash.
Creator Hash: Accessible via rpcAsset.compression.creator_hash.
Nonce: Accessible via rpcAsset.compression.leaf_id.
Index: Accessible via rpcAssetProof.node_index - 2^max_depth where max_depth is the maximum depth of the tree and can be inferred from the length of the rpcAssetProof.proof array.
Proof: Accessible via rpcAssetProof.proof.
Metadata: Currently needs to be reconstructed from various fields in the rpcAsset response.

Get parameters for instructions that replace leaves

The Bubblegum Umi library provides a getAssetWithProof helper method that fits the description above. Here's an example of how to use it using the transfer instruction. Note that, in this case, we override the leafOwner parameter as it needs to be a Signer and assetWithProof gives us the owner as a Public Key.

import { getAssetWithProof, transfer } from '@metaplex-foundation/mpl-bubblegum'

const assetWithProof = await getAssetWithProof(umi, assetId)
await transfer(umi, {
  ...assetWithProof,
  leafOwner: leafOwnerA, // As a signer.
  newLeafOwner: leafOwnerB.publicKey,
}).sendAndConfirm(umi)