Solana Mapping

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

• Mappings are defined in the src/mappings directory and are exported as a function.
• These mappings are also exported in src/index.ts.
• The mappings files are reference in project.ts under the mapping handlers.
• The mappings are run from within a Sandbox

There are different classes of mappings functions for Solana; Block handlers, Transaction Handlers, Instruction Handlers, and Log Handlers.

Block Handler

You can use block handlers to capture information each time a new block is attached to the chain, e.g. block number. To achieve this, a defined BlockHandler will be called once for every block.

Using block handlers slows your project down as they can be executed with each and every block - only use if you need to.

import { SolanaBlock } from "@subql/types-solana";

export async function handleBlock(block: SolanaBlock): Promise<void> {
  // Create a new BlockEntity with the block hash as it's ID
  const record = new BlockEntity(block.blockHash);
  record.height = BigInt(block.blockNumber);
  await record.save();
}

Transaction Handler

You can use transaction handlers to capture information about each of the transactions in a block. To achieve this, a defined TransactionHandler will be called once for every transaction. You should use Mapping Filters in your manifest to filter transactions to reduce the time it takes to index data and improve mapping performance.

import { Transaction } from "../types";

export async function handleTransaction(tx: SolanaTransaction): Promise<void> {
  logger.info(`New transaction at block ${tx.blockNumber}`);
  const txRecord = Transaction.create({
    id: tx.transaction.signatures[0],
    owner: tx.from,
    spender: await tx.args[0],
    value: BigInt(await tx.args[1].toString()),
    contractAddress: tx.to,
  });

  await txRecord.save();
}

Instruction Handler

You can use instruction handlers to capture information about each of the instructions in a block. To achieve this, a defined InstructionHandler will be called once for every instruction. You should use Mapping Filters in your manifest to filter instructions to reduce the time it takes to index data and improve mapping performance.

import { Transfer } from "../types";
import { TransferCheckedInstruction } from '../types/handler-inputs/TokenkegQfeZyiNwAJbNbGKPFXCWuBvf9Ss623VQ5DA';

export async function handleInstruction(inst: TransferCheckedInstruction): Promise<void> {
  logger.info(`New Transfer instruction at block ${inst.blockNumber}`);

  const source = getAccountByIndex(inst, inst.accounts[0]);
  const mint = getAccountByIndex(inst, inst.accounts[1]);
  const dest = getAccountByIndex(inst, inst.accounts[2]);

  const decoded = await inst.decodedData;
  assert(decoded, "Expected decoded value");

  const transferRecord = Transfer.create({
    id: `${inst.transaction.transaction.signatures[0]}-${inst.index.join('.')}`,
    amount: BigInt(decoded.data.amount),
    from: source,
    to: dest,
    blockNumber: inst.block.blockHeight,
    transactionHash: inst.transaction.transaction.signatures[0],
    date: new Date(Number(inst.block.blockTime) * 1000),
  });

  await transferRecord.save();
}

Log Handler

You can use log handlers to capture information when certain logs are included on transactions. During the processing, the log handler will receive a log as an argument with the log's typed inputs and outputs. Any type of event will trigger the mapping, allowing activity with the data source to be captured. You should use Mapping Filters in your manifest to filter events to reduce the time it takes to index data and improve mapping performance.

import { Log } from "../types";

export async function handleLog(log: SolanaLogMessage): Promise<void> {
  logger.info(`New log at block ${log.blockNumber}`);
  const logRecord = Log.create({
    id: log.transactionHash,
    value: log.args.value.toBigInt(),
    from: log.args.from,
    to: log.args.to,
    contractAddress: log.address,
  });

  await logRecord.save();
}