cw-ics721-callback-example

About Ark Protocol

Mission:

Building an InterChain NFT Hub. Technically this means:

Transitioning NFT utlities from a local, single-chain to a global and interchain level (like transfers, staking, snapshots, launchpads, marketplace, ...).

Ark Protocol is the main contributor for cw-ics721 and cw-nfts. Recent utilities we have provided are:

• ICS 721

  • InterChain transfers
  • Outgoing and incoming proxies for additional security (e.g., whitelisting IBC channels)
  • Optional receive and ack callbacks

• cw-nfts

  • cw721-expiration: For issuing time-based subscriptions and services
  • Upcoming major v0.19 release
    • Main logic moved to cw721 package for better re-use
    • Distinction between creator and minter
    • NEW CollectionInfo in cw721 package
    • NEW utility: UpdateNftInfo and UpdateCollectionInfo msg

• More InterChain utilities coming soon:

  • InterChain launchpad
  • InterChain marketplace
  • cw-ics721 v2 (onchain metadata, royalties, single-hop-only transfers, etc.)

Demo

All contracts are deployed on Stargaze and Osmosis testnet. There are deployment scripts described in scripts/SETUP.md.

This is a full example demoing how cw721 interacts with ics721, incoming, and outgoing proxies.

Demo will show how NFT and its metadata are affected using callbacks during InterChain (aka ics721) transfers:

1. Minting an NFT on Osmosis
2. Transferring NFT to Stargaze
3. Transferring Back to Osmosis

Kudos

Special thanks to Ilo and the GraviDao team. PFPs have been provided by them.

Minting an NFT on Osmosis

A minted NFT looks like this on Osmosis (source/home chain):

Transferring NFT to Stargaze

After NFT is transferred over to Stargaze, NFT on Osmosis is escrowed, and its metadata data is updated:

Note: PFP has changed from home to escrowed PFP!

On the target/sub chain, an NFT is minted by ICS721 on Stargaze:

Note: PFP has changed from home to transferred PFP!

Please also note, that ics721 transfers NFT data as-is (as provided by the collection on the home chain). PFPs on both chains are updated, using callbacks!

Transferring Back to Osmosis

Transferring an NFT back to home chain, leads to NFT being burned on subchain/Stargaze, and callback resetting PFP on home chain:

Note: PFP has resetted back home PFP!

Scripts for Testing

All scripts are availble in ./scripts:

# Mint an NFT
./scripts/mint.sh osmosis # output returns NFT id, e.g. "1"

# Transfer and relay NFT #1:
./scripts/transfer.sh osmosis 1 # output returns collection address on target chain, e.g. "stars1qfclvue79dnhmm7n5d3zce6ftza866zxl57se2s47mrfkf3cetgsew2fmj"

# Back transfer of specific collection `stars1qfclvue79dnhmm7n5d3zce6ftza866zxl57se2s47mrfkf3cetgsew2fmj`
./scripts/transfer.sh stargaze 1 stars1qfclvue79dnhmm7n5d3zce6ftza866zxl57se2s47mrfkf3cetgsew2fmj

Some explanation here regarding NFT ownership:

• check ownership
  • UI: https://testnet.arkprotocol.io/collections/CW721_ADDRESS/NFT_ID
  • CLI: source ./scripts/osmosis.env;$CLI query wasm contract-state smart $ADDR_CW721 '{"all_nft_info":{"token_id": "35"}}' --chain-id $CHAIN_ID --node $CHAIN_NODE | jq
• forward transfer:
  • NFT on source chain is escrowed/owned by $ADDR_ICS721
  • NFT on target chain is owned by $WALLET_ARKITE_PASSPORT

Next, we can test transferring an NFT via a channel that is not whitelisted. For this open ./scripts/transfer.sh and replace $CHANNEL_ID with $CHANNEL_ID_NOT_WHITELISTED. Now on transfer an ack fail (with code 5: execution error) is returned. NFT on source chain is returned back to $WALLET_ARKITE_PASSPORT.

cw-ics721 Specifics

Ark Protocol has implemented enhanced proxies. All contracts have been audited by SCV. We plan to open source our contracts in the near future - after a certain grace period on mainnet chains. Ark's proxies provides addtional securities, like: whitelisting channels, collections, and code hashes.

This way cw-ics721 secures transferring via:

• safe WLed channels and excluding unknown, unsecure channels
• avoid fragmentation (e.g. only one channel to each target chain)
• safe cw721 contracts - by WLing address and code hashes
• checks on both sides: outbound and inbound NFTs

For the rare case a chain or contracts gets compromised, Ark proxies will de-WL channels, collections either on outbound or inbound or both sides - on all required chains. As an additional measure, cw-ics721 also allows defining a one-time pauser address, allowing to halt cw-ics721 until it is explicitly unpaused again.

Contracts

Main contract is ./contracts/cw-ics721-arkite-passport. It acts as:

• a minter
• forwards incoming NFTs to ICS721 and attaching callbacks
• receive and ack callback handler
• also holds references to:
  • passport and poap collection (both cw721-base)

Callback does:

• receive callback on arkite-passport contract:
  • mutates the NFT's metadata (token uri) on target chain
  • mints a POAP NFT
• ack callback on arkite-passport contract:
  • mutates NFT on source chain

The workflow for transferring an NFT from Stargaze to Osmosis is:

• user calls send_nft to arkite-passport contract
• arkite-passport transfers NFT to target chain
  • attaches receive and ack callback as part of memo
  • forwards send_nft to outgoing proxy
  • outgoing proxy forwards send_nft to ics721
  • ics721 sends ibc message / packet to target chain
• relayer picks packet and triggers call on target chain
• ics721 processing
  • transfer nft
    • initially instantiates collection
    • mints nft and transfers to target recipient
  • forwards receive callback to

Resources

• cw-ics721 repo: https://github.com/public-awesome/cw-ics721
• ics721-plus repo (private): https://github.com/arkprotocol/ics721-plus
• cw-ics721-proxy repo: https://github.com/arkprotocol/cw-ics721-proxy