BNB Smart Chain (BSC) Manifest File

SubQuery TeamAbout 8 min

BNB Smart Chain (BSC) Manifest File

Important

We use Ethereum packages, runtimes, and handlers (e.g. @subql/node-ethereum, ethereum/Runtime, and ethereum/*Handler) for BNB Smart Chain (BSC). Since BSC is EVM-compatible, we can use the core Ethereum framework to index it.

The Manifest project.ts file can be seen as an entry point of your project and it defines most of the details on how SubQuery will index and transform the chain data. It clearly indicates where we are indexing data from, and to what on chain events we are subscribing to.

The Manifest can be in either Typescript, Yaml, or JSON format.

With the number of new features we are adding to SubQuery, and the slight differences between each chain that mostly occur in the manifest, the project manifest is now written by default in Typescript. This means that you get a fully typed project manifest with documentation and examples provided your code editor.

Below is a standard example of a basic project.ts.

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

// Can expand the Datasource processor types via the generic param
const project: EthereumProject = {
  specVersion: "1.0.0",
  version: "0.0.1",
  name: "bsc-mobox-rewards",
  description:
    "This project can be use as a starting point for developing your new BSC Testnet SubQuery project",
  runner: {
    node: {
      name: "@subql/node-ethereum",
      version: ">=3.0.0",
    },
    query: {
      name: "@subql/query",
      version: "*",
    },
  },
  schema: {
    file: "./schema.graphql",
  },
  network: {
    /**
     * chainId is the EVM Chain ID, for BSC this is 56
     * https://chainlist.org/chain/56
     */
    chainId: "56",
    /**
     * These endpoint(s) should be non-pruned archive nodes
     * Public nodes may be rate limited, which can affect indexing speed
     * When developing your project we suggest getting a private API key
     # We suggest providing an array of endpoints for increased speed and reliability
     */
    endpoint: ["https://bsc-dataseed1.binance.org"],
    dictionary: "https://dict-tyk.subquery.network/query/binance",
  },
  dataSources: [
    {
      kind: EthereumDatasourceKind.Runtime,
      startBlock: 326031, //The block on which the Mobox Farming contract was deployed

      options: {
        // Must be a key of assets
        abi: "erc20",
        // this is the contract address for Binance-Peg Ethereum Token https://bscscan.com/address/0x2170ed0880ac9a755fd29b2688956bd959f933f8
        address: "0x2170Ed0880ac9A755fd29B2688956BD959F933F8",
      },
      assets: new Map([["erc20", { file: "./abis/erc20.abi.json" }]]),
      mapping: {
        file: "./dist/index.js",
        handlers: [
          {
            kind: EthereumHandlerKind.Call,
            handler: "handleTransaction",
            filter: {
              /**
               * The function can either be the function fragment or signature
               * function: '0x095ea7b3'
               * function: '0x7ff36ab500000000000000000000000000000000000000000000000000000000'
               */
              function: "approve(address spender, uint256 rawAmount)",
            },
          },
          {
            kind: EthereumHandlerKind.Event,
            handler: "handleLog",
            filter: {
              /**
               * Follows standard log filters https://docs.ethers.io/v5/concepts/events/
               * address: "0x60781C2586D68229fde47564546784ab3fACA982"
               */
              topics: [
                "Transfer(address indexed from, address indexed to, uint256 amount)",
              ],
            },
          },
        ],
      },
    },
  ],
  repository: "https://github.com/subquery/ethereum-subql-starter",
};

// Must set default to the project instance
export default project;

Below is a standard example of the legacy YAML version (project.yaml).

Legacy YAML Manifest

specVersion: "1.0.0"

name: "bsc-subql-starter"
version: "0.0.1"
runner:
  node:
    name: "@subql/node-ethereum"
    version: "*"
  query:
    name: "@subql/query"
    version: "*"
description: "This project can be use as a starting point for developing your new BNB Smart Chain SubQuery project"
repository: "https://github.com/subquery/ethereum-subql-starter"

schema:
  file: "./schema.graphql"

network:
  # chainId is the EVM Chain ID, for BSC this is 56
  # https://chainlist.org/chain/56
  chainId: "56"
  # This endpoint must be a public non-pruned archive node
  # We recommend providing more than one endpoint for improved reliability, performance, and uptime
  # Public nodes may be rate limited, which can affect indexing speed
  # When developing your project we suggest getting a private API key and using endpoint config
  endpoint: ["https://bnb.rpc.subquery.network/public"]
  # Recommended to provide the HTTP endpoint of a full chain dictionary to speed up processing
  dictionary: "https://gx.api.subquery.network/sq/subquery/bsc-dictionary"

dataSources:
  - kind: ethereum/Runtime # We use ethereum runtime since BSC is a layer-2 that is compatible
    startBlock: 326031 # The block on which the Binance-Peg Ethereum token was deployed
    options:
      # Must be a key of assets
      abi: erc20
      address: "0x2170Ed0880ac9A755fd29B2688956BD959F933F8" # this is the contract address for Binance-Peg Ethereum Token https://bscscan.com/address/0x2170ed0880ac9a755fd29b2688956bd959f933f8
    assets:
      erc20:
        file: "erc20.abi.json"
    mapping:
      file: "./dist/index.js"
      handlers:
        - handler: handleTransaction
          kind: ethereum/TransactionHandler # We use ethereum handlers since BSC is a layer-2 that is compatible
          filter:
            ## The function can either be the function fragment or signature
            # function: '0x095ea7b3'
            # function: '0x7ff36ab500000000000000000000000000000000000000000000000000000000'
            function: approve(address spender, uint256 rawAmount)
        - handler: handleLog
          kind: ethereum/LogHandler # We use ethereum handlers since BSC is a layer-2 that is compatible
          filter:
            topics:
              ## Follows standard log filters https://docs.ethers.io/v5/concepts/events/
              - Transfer(address indexed from, address indexed to, uint256 amount)
              # address: "0x60781C2586D68229fde47564546784ab3fACA982"

Overview

Top Level Spec

Field	Type	Description
specVersion	String	The spec version of the manifest file
name	String	Name of your project
version	String	Version of your project
description	String	Description of your project
runner	Runner Spec	Runner specs info
repository	String	Git repository address of your project
schema	Schema Spec	The location of your GraphQL schema file
network	Network Spec	Detail of the network to be indexed
dataSources	DataSource Spec	The datasource to your project
templates	Templates Spec	Allows creating new datasources from this templates

Schema Spec

Field	Type	Description
file	String	The location of your GraphQL schema file

Network Spec

If you start your project by using the subql init command, you'll generally receive a starter project with the correct network settings. If you are changing the target chain of an existing project, you'll need to edit the Network Spec section of this manifest.

The chainId is the network identifier of the blockchain. Examples in BNB Smart Chain (BSC) is 56 for mainnet. See https://chainlist.org/chain/56

Additionally you will need to update the endpoint. This defines the (HTTP or WSS) endpoint of the blockchain to be indexed - this must be a full archive node. This property can be a string or an array of strings (e.g. endpoint: ['rpc1.endpoint.com', 'rpc2.endpoint.com']). We suggest providing an array of endpoints as it has the following benefits:

Increased speed - When enabled with worker threads, RPC calls are distributed and parallelised among RPC providers. Historically, RPC latency is often the limiting factor with SubQuery.
Increased reliability - If an endpoint goes offline, SubQuery will automatically switch to other RPC providers to continue indexing without interruption.
Reduced load on RPC providers - Indexing is a computationally expensive process on RPC providers, by distributing requests among RPC providers you are lowering the chance that your project will be rate limited.

Public nodes may be rate limited which can affect indexing speed, when developing your project we suggest getting a private API key from a professional RPC provider.

Field	Type	Description
chainId	String	A network identifier for the blockchain
endpoint	String or String[] or Record<String, IEndpointConfig>	Defines the endpoint of the blockchain to be indexed, this can be a string, an array of endpoints, or a record of endpoints to endpoint configs - This must be a full archive node.
dictionary	String	It is suggested to provide the HTTP endpoint of a full chain dictionary to speed up processing - read how a SubQuery Dictionary works.
bypassBlocks	Array	Bypasses stated block numbers, the values can be a `range`(e.g. `"10- 50"`) or `integer`, see Bypass Blocks

Runner Spec

Field	Type	Description
node	Runner node spec	Describe the node service use for indexing
query	Runner query spec	Describe the query service

Runner Node Spec

Field	Type	Description
name	String	`@subql/node-ethereum` We use the Ethereum node package for BSC since it is compatible with the Ethereum framework
version	String	Version of the indexer Node service, it must follow the SEMVER rules or `latest`, you can also find available versions in subquery SDK releases
options	Runner Node Options	Runner specific options for how to run your project. These will have an impact on the data your project produces. CLI flags can be used to override these.

Runner Query Spec

Field	Type	Description
name	String	`@subql/query` and `@subql/query-subgraph`
version	String	Version of the Query service, available `@subql/query` versions and `@subql/query-subgraph` versions, it also must follow the SEMVER rules or `latest`.

Runner Node Options

Field	v1.0.0 (default)	Description
historical	Boolean (true)	Historical indexing allows you to query the state at a specific block height. e.g A users balance in the past.
unfinalizedBlocks	Boolean (false)	If enabled unfinalized blocks will be indexed, when a fork is detected the project will be reindexed from the fork. Requires historical.
unsafe	Boolean (false)	Removes all sandbox restrictions and allows access to all inbuilt node packages as well as being able to make network requests. WARNING: this can make your project non-deterministic.
skipTransactions	Boolean (false)	If your project contains only event handlers and you don't access any other block data except for the block header you can speed your project up. Handlers should be updated to use `LightEthereumLog` instead of `EthereumLog` to ensure you are not accessing data that is unavailable.

Datasource Spec

Defines the data that will be filtered and extracted and the location of the mapping function handler for the data transformation to be applied.

Field	Type	Description
kind	string	ethereum/Runtime We use the Ethereum runtime for BSC since it is compatible with the Ethereum framework
startBlock	Integer	This changes your indexing start block for this datasource, set this as high as possible to skip initial blocks with no relevant data
endBlock	Integer	This sets a end block for processing on the datasource. After this block is processed, this datasource will no longer index your data. Useful when your contracts change at a certain block height, or when you want to insert data at genesis. For example, setting both the `startBlock` and `endBlock` to 320, will mean this datasource only operates on block 320
mapping	Mapping Spec

Mapping Spec

Field	Type	Description
handlers & filters	Default handlers and filters	List all the mapping functions and their corresponding handler types, with additional mapping filters.

Data Sources and Mapping

In this section, we will talk about the default BSC runtime and its mapping. Here is an example:

{
  dataSources: [
    {
      kind: EthereumDatasourceKind.Runtime, // Indicates that this is default runtime
      startBlock: 1, // This changes your indexing start block, set this higher to skip initial blocks with less data
      options: {
        // Must be a Record of assets
        abi: "erc20",
        // # this is the contract address for your target contract
        address: "0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2",
      },
      assets: new Map([["erc20", { file: "./abis/erc20.abi.json" }]]),
      mapping: {
        file: "./dist/index.js", // Entry path for this mapping
        handlers: [
          /* Enter handers here */
        ],
      },
    },
  ];
}

Mapping Handlers and Filters

The following table explains filters supported by different handlers.

Your SubQuery project will be much more efficient when you only use TransactionHandler or LogHandler handlers with appropriate mapping filters (e.g. NOT a BlockHandler).

Handler	Supported filter
ethereum/BlockHandler	`modulo`, `timestamp`
ethereum/TransactionHandler	`function` filters (either be the function fragment or signature), `from` (address), `to` (address)
ethereum/LogHandler	`topics` filters, and `address`

Default runtime mapping filters are an extremely useful feature to decide what block, event, or extrinsic will trigger a mapping handler.

Only incoming data that satisfies the filter conditions will be processed by the mapping functions. Mapping filters are optional but are highly recommended as they significantly reduce the amount of data processed by your SubQuery project and will improve indexing performance.

The modulo filter allows handling every N blocks, which is useful if you want to group or calculate data at a set interval. The following example shows how to use this filter.

filter:
  modulo: 50 # Index every 50 blocks: 0, 50, 100, 150....

The timestamp filter is very useful when indexing block data with specific time intervals between them. It can be used in cases where you are aggregating data on a hourly/daily basis. It can be also used to set a delay between calls to blockHandler functions to reduce the computational costs of this handler.

The timestamp filter accepts a valid cron expression and runs on schedule against the timestamps of the blocks being indexed. Times are considered on UTC dates and times. The block handler will run on the first block that is after the next iteration of the cron expression.

filter:
  # This cron expression will index blocks with at least 5 minutes interval
  # between their timestamps starting at startBlock given under the datasource.
  timestamp: "*/5 * * * *"

Note

We use the cron-converter package to generate unix timestamps for iterations out of the given cron expression. So, make sure the format of the cron expression given in the timestamp filter is compatible with the package.

Some common examples

  # Every minute
  timestamp: "* * * * *"
  # Every hour on the hour (UTC)
  timestamp: "0 * * * *"
  # Every day at 1am UTC
  timestamp: "0 1 * * *"
  # Every Sunday (weekly) at 0:00 UTC
  timestamp: "0 0 * * 0"

Simplifying your Project Manifest for a large number contract addresses

If your project has the same handlers for multiple versions of the same type of contract your project manifest can get quite repetitive. e.g you want to index the transfers for many similar ERC20 contracts, there are ways to better handle a large static list of contract addresses.

Note that there is also dynamic datasources for when your list of addresses is dynamic (e.g. you use a factory contract).

Real-time indexing (Block Confirmations)

As indexers are an additional layer in your data processing pipeline, they can introduce a massive delay between when an on-chain event occurs and when the data is processed and able to be queried from the indexer.

SubQuery provides real time indexing of unconfirmed data directly from the RPC endpoint that solves this problem. SubQuery takes the most probabilistic data before it is confirmed to provide to the app. In the unlikely event that the data isn’t confirmed and a reorg occurs, SubQuery will automatically roll back and correct its mistakes quickly and efficiently - resulting in an insanely quick user experience for your customers.

To control this feature, please adjust the --block-confirmations command to fine tune your project and also ensure that historic indexing is enabled (enabled by default)

Bypass Blocks

Bypass Blocks allows you to skip the stated blocks, this is useful when there are erroneous blocks in the chain or when a chain skips a block after an outage or a hard fork. It accepts both a range or single integer entry in the array.

When declaring a range use an string in the format of "start - end". Both start and end are inclusive, e.g. a range of "100-102" will skip blocks 100, 101, and 102.

{
  network: {
    bypassBlocks: [1, 2, 3, "105-200", 290];
  }
}

Endpoint Config

This allows you to set specific options relevant to each specific RPC endpoint that you are indexing from. This is very useful when endpoints have unique authentication requirements, or they operate with different rate limits.

Here is an example of how to set an API key in the header of RPC requests in your endpoint config.

{
  network: {
    endpoint: {
      "https://bnb.rpc.subquery.network/public": {
        headers: {
          "x-api-key": "your-api-key",
        },
        // NOTE: setting this to 0 will not use batch requests
        batchSize: 5
      }
    }
  }
}