Ethereum Quick Start - BAYC (Simple)

SubQuery TeamAbout 5 min

Ethereum Quick Start - BAYC (Simple)

The goal of this article is to provide a comprehensive guide to setting up an indexer for the Bored Ape Yacht Club (BAYC) smart contract. By the end of this guide, readers will have a clear understanding of the following what BAYC is and why its smart contract data is valuable for indexing. This guide also shows how to set up an indexer, step by step, to track and index data from the BAYC smart contract on the Ethereum blockchain.

This guide is designed to seamlessly lead you through the steps of configuring your personal BAYC SubQuery indexer.

Setting Up the Indexer

In this BAYC indexing project, our main goal is to set up the indexer to only collect information from one smart contract: 0xBC4CA0EdA7647A8aB7C2061c2E118A18a936f13D, the BAYC contract.

The BAYC contract builds on OpenZeppelin's ERC721 with special BAYC features. You can find the contract's source code on Etherscan or Github for easier reading.

In the earlier Quickstart section , you should have taken note of three crucial files. To initiate the setup of a project from scratch, you can proceed to follow the steps outlined in the initialisation description.

As a prerequisite, you will need to generate types from the ABI files of each smart contract. Additionally, you can kickstart your project by using the EVM Scaffolding approach (detailed here). You'll find all the relevant events to be scaffolded in the documentation for each type of smart contract.

Note

You can find the full and detailed code here to see all the intricate details.

Your Project Manifest File

The Project Manifest file is an entry point to your project. It defines most of the details on how SubQuery will index and transform the chain data.

For EVM chains, there are three types of mapping handlers (and you can have more than one in each project):

BlockHanders: On each and every block, run a mapping function
TransactionHandlers: On each and every transaction that matches optional filter criteria, run a mapping function
LogHanders: On each and every log that matches optional filter criteria, run a mapping function

You only need to set up one handler to index a specific type of log from this contract, which is the OrderFulfilled log. Update your manifest file to look like this:

import {
  EthereumProject,
  EthereumDatasourceKind,
  EthereumHandlerKind,
} from "@subql/types-ethereum";

const project: EthereumProject = {
  specVersion: "1.0.0",
  version: "0.0.1",
  name: "ethereum-subql-starter",
  description:
    "This project can be use as a starting point for developing your new Ethereum SubQuery project",
  runner: {
    node: {
      name: "@subql/node-ethereum",
      version: ">=3.0.0",
    },
    query: {
      name: "@subql/query",
      version: "*",
    },
  },
  schema: {
    file: "./schema.graphql",
  },
  network: {
    chainId: "1",
    endpoint: ["https://eth.api.onfinality.io/public"],
    dictionary: "https://gx.api.subquery.network/sq/subquery/eth-dictionary",
  },
  dataSources: [
    {
      kind: EthereumDatasourceKind.Runtime,
      startBlock: 12287507,

      options: {
        abi: "bayc",
        address: "0xBC4CA0EdA7647A8aB7C2061c2E118A18a936f13D",
      },
      assets: new Map([["bayc", { file: "./abis/bayc.abi.json" }]]),
      mapping: {
        file: "./dist/index.js",
        handlers: [
          {
            kind: EthereumHandlerKind.Call,
            handler: "handleMint",
            filter: {
              function: "mintApe(uint256)",
            },
          },
          {
            kind: EthereumHandlerKind.Event,
            handler: "handleTransfer",
            filter: {
              topics: [
                "Transfer(address indexed from, address indexed to, uint256 amount)",
              ],
            },
          },
        ],
      },
    },
  ],
  repository: "https://github.com/subquery/ethereum-subql-starter",
};

export default project;

As evident in the manifest file, this project includes two handlers: firstly, a transaction handler responsible for capturing the mintApe function, and secondly, a log handler tasked with indexing the Transfer log.

Note

Check out our Manifest File documentation to get more information about the Project Manifest (project.ts) file.

Update Your GraphQL Schema File

The schema.graphql file determines the shape of your data from SubQuery due to the mechanism of the GraphQL query language. Hence, updating the GraphQL Schema file is the perfect place to start. It allows you to define your end goal right at the start.

Now, let's think about what information we can get from this smart contract for later searching.

type Transfer @entity {
  id: ID!
  from: String!
  to: String!
  tokenId: BigInt!
  blockNumber: BigInt!
  transactionHash: String!
  timestamp: BigInt!
  date: Date!
  boredApe: BoredApe!
}

type Mint @entity {
  id: ID!
  minter: String!
  boredApe: BoredApe!
  timestamp: BigInt!
  date: Date!
}

type BoredApe @entity {
  id: ID!
  creator: String!
  currentOwner: String!
  blockNumber: BigInt!
  prorepties: Properties!
}

type Properties @jsonField {
  image: String
  background: String
  clothes: String
  earring: String
  eyes: String
  fur: String
  hat: String
  mouth: String
}

Three entities are derived from the handlers mentioned earlier: BoredApes, Mint (used to store data associated with BoredApe transaction creation), and Transfers of BoredApes. The Bored Ape entity features a currentOwner, which changes with each transfer, and it includes properties like metadata stored on IPFS. Clearly, these apes were initially created using a specific function and may have been transferred, and this project monitors both types of transaction entities. Both the Transfer and Mint entities are associated with a BoredApe, enabling retrieval of all transfers and the Mint entity within the Bored Ape entity.

Note

Importantly, these relationships can not only establish one-to-many connections but also extend to include many-to-many associations. To delve deeper into entity relationships, you can refer to this section. If you prefer a more example-based approach, our dedicated Hero Course Module can provide further insights.

SubQuery simplifies and ensures type-safety when working with GraphQL entities, smart contracts, events, transactions, and logs. The SubQuery CLI will generate types based on your project's GraphQL schema and any contract ABIs included in the data sources.

yarn

yarn codegen

npm

npm run-script codegen

This action will generate a new directory (or update the existing one) named src/types. Inside this directory, you will find automatically generated entity classes corresponding to each type defined in your schema.graphql. These classes facilitate type-safe operations for loading, reading, and writing entity fields. You can learn more about this process in the GraphQL Schema section.

It will also generate a class for every contract event, offering convenient access to event parameters, as well as information about the block and transaction from which the event originated. You can find detailed information on how this is achieved in the EVM Codegen from ABIs section. All of these types are stored in the src/types/abi-interfaces and src/types/contracts directories.

You can conveniently import all these types:

import { Transfer, BoredApe, Properties, Mint } from "../types";
import { TransferLog } from "../types/abi-interfaces/BaycAbi";
import { MintApeTransaction } from "../types/abi-interfaces/BaycAbi";

Check out the GraphQL Schema documentation to get in-depth information on schema.graphql file.

Now that you have made essential changes to the GraphQL Schema file, let’s proceed ahead with the Mapping Function’s configuration.

Add a Mapping Function

Mapping functions define how blockchain data is transformed into the optimised GraphQL entities that we previously defined in the schema.graphql file.

Note

For more information on mapping functions, please refer to our Mappings documentation.

Writing mappings for this smart contract is a straightforward process. To provide better context, we've included this handler in a separate file mappingHandlers.ts within the src/mappings directory. Let's start by importing the necessary modules.

import { TransferLog } from "../types/abi-interfaces/BaycAbi";
import { Transfer, BoredApe, Properties, Mint } from "../types";
import { MintApeTransaction } from "../types/abi-interfaces/BaycAbi";
import fetch from "node-fetch";
import assert from "assert";

Transfer, BoredApe, Mint, Properties and other models were created in a previous step. On the other hand, OrderFulfilledLog is a TypeScript model automatically generated by the SubQuery SDK to make it easier to work with events.

You may have noticed that we import the fetch function from the "node-fetch" library. This import is necessary for querying an HTTP gateway that retrieves data from IPFS. Since we're fetching data from external API endpoints, it's essential to launch the node with the --unsafe flag. For further details, please refer to the documentation.

As a recap of the setup procedure detailed in the Manifest File, it's important to note that this project includes two handlers: handleMint and handleTransfer. In the provided example, we've established a connection between these handlers. Now, let's examine the end code:

async function getOrCreateApe(event: TransferLog): Promise<BoredApe> {
  assert(event.args);
  let boredApe = await BoredApe.get(event.args.tokenId.toString());

  if (boredApe == undefined) {
    const ipfshash = "QmeSjSinHpPnmXmspMjwiXyN6zS4E9zccariGR3jxcaWtq";
    let tokenURI = "/" + event.args.tokenId.toString();
    let fullURI = ipfshash + tokenURI;

    let content = await (await fetch("https://ipfs.io/ipfs/" + fullURI)).json();

    const properties: Properties = {};

    if (content) {
      properties.image = content.image;
      let attributes = content.attributes;
      if (attributes) {
        for (const attribute of attributes) {
          let trait_type = attribute.trait_type;
          let value_type = attribute.value;

          let trait: string;
          let value: string;

          if (trait_type && value_type) {
            trait = trait_type.toString();
            value = value_type.toString();

            if (trait && value) {
              if (trait == "Background") {
                properties.background = value;
              }

              if (trait == "Clothes") {
                properties.clothes = value;
              }

              if (trait == "Earring") {
                properties.earring = value;
              }

              if (trait == "Eyes") {
                properties.eyes = value;
              }

              if (trait == "Fur") {
                properties.fur = value;
              }

              if (trait == "Hat") {
                properties.hat = value;
              }

              if (trait == "Mouth") {
                properties.mouth = value;
              }
            }
          }
        }
      }
    }

    boredApe = BoredApe.create({
      id: event.args.tokenId.toString(),
      creator: event.args.to,
      currentOwner: event.args.to,
      blockNumber: BigInt(event.blockNumber),
      prorepties: properties,
    });
  }

  boredApe.save();
  return boredApe;
}

export async function handleMint(
  transaction: MintApeTransaction,
): Promise<void> {
  assert(transaction.logs);
  let transferLog: TransferLog = transaction.logs.find(
    (e) =>
      e.topics[0] ===
      "0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef",
  ) as TransferLog;
  let boredApe = await getOrCreateApe(transferLog);
  let mint = Mint.create({
    id: transaction.hash.toString(),
    minter: transaction.from.toString(),
    boredApeId: boredApe.id,
    timestamp: transaction.blockTimestamp,
    date: new Date(Number(transaction.blockTimestamp)),
  });
  mint.save();
}

export async function handleTransfer(event: TransferLog): Promise<void> {
  assert(event.args);
  let boredApe = await getOrCreateApe(event);

  let transfer = Transfer.create({
    id: event.transactionHash + event.logIndex,
    from: event.args.from,
    to: event.args.to,
    tokenId: event.args.tokenId.toBigInt(),
    blockNumber: BigInt(event.blockNumber),
    transactionHash: event.transactionHash,
    timestamp: event.transaction.blockTimestamp,
    date: new Date(Number(event.transaction.blockTimestamp)),
    boredApeId: boredApe.id,
  });
  transfer.save();

  boredApe.currentOwner = event.args.to;
  boredApe.blockNumber = BigInt(event.blockNumber);
  boredApe.save();
}

This code snippet demonstrates handleMint that is handling the minting of new Bored Apes. Firstly, it asserts that transaction.logs exists, then it finds a specific type of log within the transaction logs (based on a topic hash) that represents a token transfer. Later it calls getOrCreateApe to create or retrieve the associated BoredApe. Finally, creates a Mint object with information about the minting transaction and saves it.

The second handler is handleTransfer, which processes transfers of Bored Apes between users. It takes a TransferLog object as an argument, asserts that event.args exists; calls getOrCreateApe to create or retrieve the associated BoredApe; creates a Transfer object with information about the transfer event and saves it. Lastly, it updates the currentOwner and blockNumber properties of the BoredApe object and saves it.

Both handlers use getOrCreateApe function. It attempts to retrieve a BoredApe object from some data source using the token ID obtained from event.args. If the BoredApe does not exist, it proceeds to create it. Apart from the data obtained from the logs it fetches additional information from an IPFS, such as image and attributes, and populates a properties object. Finally, it saves the BoredApe object and returns it.

🎉 At this stage, we have successfully incorporated all the desired entities that can be retrieved from BAYC smart contracts. For each of these entities, we've a single mapping handler to structure and store the data in a queryable format.

Note

Check the final code repository here to observe the integration of all previously mentioned configurations into a unified codebase.

Note

For more information on mapping functions, please refer to our Mappings documentation.

Build Your Project

Next, build your work to run your new SubQuery project. Run the build command from the project's root directory as given here:

yarn

yarn build

npm

npm run-script build

Important

Whenever you make changes to your mapping functions, you must rebuild your project.

Now, you are ready to run your first SubQuery project. Let’s check out the process of running your project in detail.

Whenever you create a new SubQuery Project, first, you must run it locally on your computer and test it and using Docker is the easiest and quickiest way to do this.

Run Your Project Locally with Docker

The docker-compose.yml file defines all the configurations that control how a SubQuery node runs. For a new project, which you have just initialised, you won't need to change anything.

However, visit the Running SubQuery Locally to get more information on the file and the settings.

Run the following command under the project directory:

yarn

yarn start:docker

npm

npm run-script start:docker

Note

It may take a few minutes to download the required images and start the various nodes and Postgres databases.

Query your Project

Next, let's query our project. Follow these three simple steps to query your SubQuery project:

Open your browser and head to http://localhost:3000.
You will see a GraphQL playground in the browser and the schemas which are ready to query.
Find the Docs tab on the right side of the playground which should open a documentation drawer. This documentation is automatically generated and it helps you find what entities and methods you can query.

Try the following queries to understand how it works for your new SubQuery starter project. Don’t forget to learn more about the GraphQL Query language.

query {
  boredApes{
    nodes {
      id
      from
      to
      tokenId
      blockNumber
      transactionHash
      timestamp
      mints {
        nodes {
          id
          minter
          timestamp
          date
        }
      }
      transfers {
        nodes {
          id
          timestamp
          date
          from
          to
          transactionHash
        }
      }
    }
}

What's next?

Congratulations! You have now a locally running SubQuery project that accepts GraphQL API requests for transferring data.

Tip

Find out how to build a performant SubQuery project and avoid common mistakes in Project Optimisation.

Click here to learn what should be your next step in your SubQuery journey.