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Version: v0.50.x

Non-fungible Token Demo

You will build a new chain with CosmWasm, enabling support for smart contracts on a new Cosmos-SDK application. You will download a pre-built contract, upload it, and interact with it to transfer the ownership of some data.

If you do not know what an NFT is, you can read about them here: investopedia.com/non-fungible-tokens-nft.

Warning

Some parts of this tutorial will not have the added context about spawn's inner workings or how commands work. Run through Build Your Application for this context.

Prerequisites​

Danger

Some machines like Windows will not work with running the testnet. This is a limitation of the operating system hardware with wasm and required C language libraries / DLLs.

For the best experience, try make testnet or use a Linux machine or a cloud-based linux instance from Hetzner or Digital Ocean for $6 per month.

Create your chain​

Build a new chain that has CosmWasm configured.

GITHUB_USERNAME=rollchains

spawn new rollchain \
--consensus=proof-of-stake \
--bech32=roll \
--denom=uroll \
--bin=rolld \
--disabled=block-explorer \
--org=${GITHUB_USERNAME}
View UI Selector

If you remove the --disabled flag; a more intuitive UI selection approach will be taken. Make sure CosmWasm is selected with the green arrow, then press done.

Image

Start the testnet​

Note

If make sh-testnet does not start due to a port bind error, you can kill your previously running testnet with killall -9 rolld, then try again.

# move into the chain directory
cd rollchain

# - Installs the binary
# - Setups the default keys with funds
# - Starts the chain in your shell
make sh-testnet

Verify CosmWasm is enabled​

rolld q wasm params
Expected Output
code_upload_access:
  addresses: []
  permission: Everybody
  instantiate_default_permission: Everybody

Upload the contract to the network​

You will use the CW721 contract for your NFT journey. CW721 stands for CosmWasm 721. 721 corresponds to the Ethereum specification for NFTs. Understanding this is out of scope for this tutorial. Just know you can create, transfer, and query data.

Download the contract code from the CosmWasm NFTs repository, then upload it to the network with the application binary.

# Download the the NFT contract to your machine
curl -LO https://github.com/public-awesome/cw-nfts/releases/download/v0.19.0/cw721_base.wasm

# Upload the source code to the chain
# - gas is is amount of compute resources to allocate.
rolld tx wasm store ./cw721_base.wasm --from=acc0 \
    --gas=auto --gas-adjustment=2.0 --yes

Verify the code was uploaded​

# Code id: "1" is available
rolld q wasm list-code

# See the details (A lot of spam)
rolld q tx 4601FBACBDF93E4309D92E968F8B4E7F9177BCB132B65AA363AFDC26FE6B5CB6
Expected Code Info
(main) -> $ rolld q wasm list-code
code_infos:
- code_id: "1"
  creator: roll1hj5fveer5cjtn4wd6wstzugjfdxzl0xpg2te87
  data_hash: E13AA30E0D70EA895B294AD1BC809950E60FE081B322B1657F75B67BE6021B1C
  instantiate_permission:
    addresses: []
    permission: Everybody
pagination:
  next_key: null
  total: "0"

Create a new NFT collection​

With the source now uploaded, anyone can create a new NFT collection with this base contract code now on the chain. This will be a new contract that only you control. Now, instantiate the contract to create the new NFT collection.

Instantiate Format Source

You can find the instantiate, execute, and query messages (json) formats in the contract source code.

packages/cw721/src/msg.rs
loading...
Warning

Notice the MESSAGE= below has no spaces in the JSON. This is required for the command line to parse it correctly. Failure to do so will result in the error

ERR failure when running app err="accepts 2 arg(s), received 3"

# Get our account address for the acc0 wallet / key.
rolld keys show acc0 -a # roll1hj5fveer5cjtn4wd6wstzugjfdxzl0xpg2te87

# Create the NFT collection with our account
# as the authorized minter / creator for new NFTs.
MESSAGE='{"name":"Roll","symbol":"ROLL","minter":"roll1hj5fveer5cjtn4wd6wstzugjfdxzl0xpg2te87"}'

# Create the NFT collection
rolld tx wasm instantiate 1 $MESSAGE --no-admin --from=acc0 --label="my-nft" \
    --gas=auto --gas-adjustment=2.0 --yes

Contract address​

A contract address is where all the collection and information is stored. It never changes and is the unique identifier for interaction. Think of this similar to a website, google.com always brings you to google search. NFT_CONTRACT is always the RollNFTs collection.

# View all contract addresses a wallet has created
rolld q wasm list-contracts-by-creator roll1hj5fveer5cjtn4wd6wstzugjfdxzl0xpg2te87

# The contract address for the NFT collection just created
NFT_CONTRACT=roll14hj2tavq8fpesdwxxcu44rty3hh90vhujrvcmstl4zr3txmfvw9sjczpjh

Create an NFT in the collection​

The acc0 account now must create the first NFT in the collection since it is the minter. Specify the unique ID (1), the owner (acc0), and some data to be associated with this NFT. Set the url of a sunflower image as the metadata for this tutorial.

Note

The token_uri is a URL that points to the metadata of the NFT. This can be a JSON object or a URL to a JSON object. This URL can be a link to an external service like IPFS, or the raw text directly. The contract does not care, it is up to you to manage the data and build the services around it.

Execute Format Source
packages/cw721/src/msg.rs
loading...
MESSAGE='{"mint":{"token_id":"1","owner":"roll1hj5fveer5cjtn4wd6wstzugjfdxzl0xpg2te87","token_uri":"https://onlinejpgtools.com/images/examples-onlinejpgtools/sunflower.jpg"}}'

rolld tx wasm execute $NFT_CONTRACT $MESSAGE --from=acc0 \
    --gas=auto --gas-adjustment=2.0 --yes

Grab this NFT data​

There is now an NFT with the ID of 1 owned by roll1hj5fveer5cjtn4wd6wstzugjfdxzl0xpg2te87. Now query the contract to see the data and verify it is correct.

Query Format Source
packages/cw721/src/msg.rs
loading...
packages/cw721/src/msg.rs
loading...
# Get who is the owner of ID 1
rolld q wasm state smart $NFT_CONTRACT '{"owner_of":{"token_id":"1"}}'

# Retrieve the NFT info
rolld q wasm state smart $NFT_CONTRACT '{"nft_info":{"token_id":"1"}}'

Transfer the NFT to another account​

Now move the token from the originally minted account (acc0) to another account (acc1). This is a simple transfer of ownership to move who owns the data.

Execute Format Source
packages/cw721/src/msg.rs
loading...
# Recipient account
rolld keys show acc1 -a # roll1efd63aw40lxf3n4mhf7dzhjkr453axur57cawh

MESSAGE='{"transfer_nft":{"recipient":"roll1efd63aw40lxf3n4mhf7dzhjkr453axur57cawh","token_id":"1"}}'
rolld tx wasm execute $NFT_CONTRACT $MESSAGE --from=acc0 --gas=auto --gas-adjustment=2.0 --yes

# Get who is the owner of 1
# Moved to: roll1efd63aw40lxf3n4mhf7dzhjkr453axur57cawh
rolld q wasm state smart $NFT_CONTRACT '{"owner_of":{"token_id":"1"}}'

Conclusion​

In this tutorial, you built a new chain with CosmWasm enabled, launched a testnet for it, and launched an NFT collection! You uploaded a contract, created an NFT, and transferred it to another account. This is the foundation for building a new unique marketplace or game on the Interchain.