This is the first post in our brand new Astra DB Crypto Blog Series - everything you need to know about Web3. For the debut, we’ll introduce you to NFTs and walk you through how you can load them into DataStax Astra DB — a multi-cloud database-as-service (DBaaS) built on Apache Cassandra. 

In this first post, we’ll give you a quick introduction to NFTs and how you can use the serverless DataStax Astra DB to access your NFTs easily and at scale. 

You’ll learn exactly what NFTs are, the types of NFT smart contracts, and how to use the Astra DB data loader to load every NFT ever minted into Astra DB.

Let’s get started. 

NFT Basics

NFTs stands for Non-Fungible Token. In short, NFTs are:

• Digital assets representing unique objects like art, tickets, music, and videos
• Purchased and sold using Cryptocurrencies (like Ether)
• Unique and cannot be replaced (no two NFTs are the same)
• Created through a process called minting
• Supported on multiple blockchains. Most NFTs are on the Ethereum blockchain, but other chains like Solana are also supported
• Follow two NFT standards (ERC-721 and ERC-1155)

Let’s dig a little further into that last point. 

Two NFT Standards

Think of standards as a consistent set of APIs for developers to interact with NFTs. The two standards are:

• ERC-721 (Single Token Standard)

• A single deployed contract to manage one token
• Example: Bored Ape Yacht Club
• Events: Transfer, Approval, ApprovalForAll
• Functions: balanceOf, ownerOf, safeTransferFrom, transferFrom, approve, setApprovalForAll, getApproved, isApprovedForAll, tokenURI

• ERC-1155 (Multiple Token Standard)

• A single deployed contract to manage one or many tokens
• Example: Billionaire NFT Club
• Events: TransferSingle, TransferBatch, ApprovalForAll, URI
• Functions: safeTransferFrom, safeBatchTransferFrom, balanceOf, balanceOfBatch, setApprovalForAll, isApprovedForAll, uri

Pulling NFT Transfers

Now let’s go through the steps to pull NFT transfers and grab the metadata that you’ll store in Astra DB later on. 

1. Listen for new blocks to be mined, get the block number for the newly minted block. 

web3.eth.subscribe("newBlockHeaders", (err, result) => { const { number } = result; });

1. Get the block details using the block number.
   
   

const block = await web3.eth.getBlock(blockNumber);

1. Grab the transaction receipts by iterating through the block transactions.
   
   

for ( let transactionNo = 0; transactionNo < block.transactions.length; transactionNo++ ) { const receipt = web3.eth.getTransactionReceipt(transaction); }

1. The first log of each transaction recipient will contain an event signature. NFTs can be transferred in three ways: TransferSingle, TransferBatch, Transfer. If the decoded log matches one of the three transfer event signatures, you’ve detected an NFT transfer.
   
   You can use a tool like 4Byte.directory to decode signatures.

const ERC1155_TRANSFER_SINGLE_TOPIC = "0xc3d58168c5ae7397731d063d5bbf3d657854427343f4c083240f7aacaa2d0f62"; for (let logNo = 0; logNo < transactionReceipt.logs.length; logNo++) { const firstTopic = transactionReceipt.logs[logNo].topics[0]; if (firstTopic === ERC1155_TRANSFER_SINGLE_TOPIC) { console.log('NFT Transfer Detected'); } }

1. Once you’ve detected a NFT transfer, you can pull additional metadata on the NFT, using the uri function: tokenUri (for 721s) or uri (for 1155s) function.

const abi: AbiItem = isErc1155 ? { name: "uri(uint256)", type: "function", inputs: [ { type: "uint256", name: "id", }, ], } : { name: "tokenURI(uint256)", type: "function", inputs: [ { type: "uint256", name: "_tokenId", }, ], }; const res = await web3.eth.call({ to: contractAddress, data: web3.eth.abi.encodeFunctionCall(abi, [tokenId.toString()]), }); uri = web3.eth.abi.decodeParameters(["string"], res);

1. IPFS (the Interplanetary File System) is commonly used to store NFT metadata. You can convert IPFS links to JSON using the ipfs.io gateway.
   
   

const res = await axios.get( `https://gateway.ipfs.io/ipfs/${url?.replace("ipfs://", "")}` ); return res?.data;

1. You’re done! Now you’re ready to store the NFT metadata with the Astra DB Document API.

const astraClient = await createClient({ astraDatabaseId: process.env.ASTRA_DB_ID, astraDatabaseRegion: process.env.ASTRA_DB_REGION, applicationToken: process.env.ASTRA_DB_APPLICATION_TOKEN, }); const nftsCollection = astraClient.namespace("app").collection("eth"); const nft = await nftsCollection.create(contractAddress, { tokenId, metadata });

You can create a free Astra account or simply clone the NFT dataset to your Astra account with the steps below.

Create a database in Astra DB

1. First, head over to the dashboard and hit the button “Create Database”. 

Figure 1: Screenshot of Astra DB dashboard option to create a database.

1. Enter the database name and keyspace name, then select a provider and region. 

Database Name: NFT

Keyspace: eth

Provider: Google Cloud

Region: us-east1

Figure 2: Screenshot of new database information.

1. Next, navigate to the Data Loader and load the sample dataset, which in this case is Ethereum NFTs.

Figure 3: Screenshot of options to load a dataset.

1. Select the partition key and clustering column, and finish loading the table. Use the following information: 

Partition Key: contact_address

Clustering Column: token_id

Figure 4: Screenshot of key and clustering fields.

1. Navigate to the CQL Console and run queries against the Ethereum NFT dataset you loaded earlier. 

Figure 5: Screenshot of CQL Console option.

Now that’s all locked and loaded, we can move onto searching for an NFT in your database.

Search for an individual NFT

Here’s what we want to see when searching for an NFT. 

Figure 6: Screenshot of an example NFT (Source).

SELECT * FROM eth.nfts WHERE contract_address='0x36D7b711390D34e8fe26ad8f2bB14E7C8f0c56e9' AND token_id='4665';

Your output should look like this:

contract_address | 0x36D7b711390D34e8fe26ad8f2bB14E7C8f0c56e9 token_id | 699 block_number | 14843353 metadata | {"name":"Okay Duck Yacht Club #699","description":"Ducks are quackin'. Join the Yacht Club and be Okay.","image":"ipfs://QmUmnn8CrWyukriFL2ZMA4jVGVTAYMgwfGXxWVvBEGQ3nu/699.png","dna":"834ac0d3ee85574099881370a3cc19dec924d8c5","edition":699,"attributes":[{"trait_type":"Background","value":"Purple"},{"trait_type":"Body","value":"Cream"},{"trait_type":"Eyes","value":"Not Okay"},{"trait_type":"Eyewear","value":"Eyepatch"},{"trait_type":"Beak","value":"Cigar"},{"trait_type":"Clothes","value":"Leather Jacket"},{"trait_type":"Hat","value":"Sailor Hat"}]} name | Okay Duck Yacht Club owner_of | 0x6f04aa40c062a35d5149b85d62db94e29025bf17 symbol | ODYC token_standard | ERC721 token_uri | ipfs://QmUapkBYTtVpahj7gmZiAGDeSmBy5hG4HkUW1yiye1eQNC/699.json

 

Search for all NFTs in a block using storage attached indexes

SELECT * FROM eth.nfts WHERE block_number=14843498 ALLOW FILTERING;

This will return all the NFTs that were transacted during the block 14843498. 

Search for all NFTs with name = ‘Okay Duck Yacht Club’

SELECT * FROM eth.nfts WHERE name='Okay Duck Yacht Club' ALLOW FILTERING;

This returns 19 results in the dataset, as shown below.

...rows 1-17 contract_address | 0x36D7b711390D34e8fe26ad8f2bB14E7C8f0c56e9 token_id | 730 block_number | 14843493 metadata | {"name":"Okay Duck Yacht Club #730","description":"Ducks are quackin'. Join the Yacht Club and be Okay.","image":"ipfs://QmUmnn8CrWyukriFL2ZMA4jVGVTAYMgwfGXxWVvBEGQ3nu/730.png","dna":"e1e3ec3fdf469d10e31ab6f8192fa770794b6e3b","edition":730,"attributes":[{"trait_type":"Background","value":"Lavender"},{"trait_type":"Body","value":"Bloody"},{"trait_type":"Eyes","value":"Doped"},{"trait_type":"Eyewear","value":"None"},{"trait_type":"Beak","value":"Quackin'"},{"trait_type":"Clothes","value":"Skeleton Shirt"},{"trait_type":"Hat","value":"Halo"}]} name | Okay Duck Yacht Club owner_of | 0x0000000000000000000000005d987f2f1689ecd4c21f1e73e2f12762570fded5 symbol | ODYC token_standard | ERC721 token_uri | ipfs://QmUapkBYTtVpahj7gmZiAGDeSmBy5hG4HkUW1yiye1eQNC/730.json @ Row 19 contract_address | 0x36D7b711390D34e8fe26ad8f2bB14E7C8f0c56e9 token_id | 987 block_number | 14843324 metadata | {"name":"Okay Duck Yacht Club #987","description":"Ducks are quackin'. Join the Yacht Club and be Okay.","image":"ipfs://QmUmnn8CrWyukriFL2ZMA4jVGVTAYMgwfGXxWVvBEGQ3nu/987.png","dna":"68813b24a7c642676b3e63dd0b05c22947f0335e","edition":987,"attributes":[{"trait_type":"Background","value":"Light Blue"},{"trait_type":"Body","value":"Cream"},{"trait_type":"Eyes","value":"Not Okay"},{"trait_type":"Eyewear","value":"Heart Shaped Glasses "},{"trait_type":"Beak","value":"Quackin'"},{"trait_type":"Clothes","value":"Black Sleeveless Shirt"},{"trait_type":"Hat","value":"Halo"}]} name | Okay Duck Yacht Club owner_of | 0x0000000000000000000000001ebc712c4fe85d8bf73be303028311d600cb8ec4 symbol | ODYC token_standard | ERC721 token_uri | ipfs://QmUapkBYTtVpahj7gmZiAGDeSmBy5hG4HkUW1yiye1eQNC/987.json

And there you have it! You’ve just loaded an entire dataset of NFTs into your Astra DB in just a few steps.

Note that this is just the tip of the iceberg of how you can wield Astra DB to easily manage NFTs, so stay tuned for the next posts in this Astra DB Crypto Blog Series to learn much more. In the meantime, if you have any questions or need help with any of the instructions above, ping us at hello@datastax.com.

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Resources

1. DataStax Astra DB
2. Astra DB Data Loader | DataStax Documentation 
3. Developing with the Astra DB Document API 
4. EIP-721: Non-Fungible Token Standard
5. 8520 - Bored Ape Yacht Club | OpenSea 
6. EIP-1155: Multi Token Standard 
7. Baby Dragon Club #3573 - Billionaire NFT Club | OpenSea 
8. Ethereum Signature Database