Sending a Query
Instructions for sending an on-chain query into Axiom.
const qb = ax.newQueryBuilder();
Our initial release allows queries with up to 64 pieces of on-chain data. Each piece of on-chain data is specified by
blockNumber(required), address (optional), and slot (optional), which parametrize block headers, accounts, and account storage, respectively. To create a query, add these to the
QueryBuilder using the append method. If you need help finding the storage slot corresponding to a contract variable, see our page on finding storage slots or look up the relevant storage slot at evm.storage.const UNI_V2_ADDR = "0x5C69bEe701ef814a2B6a3EDD4B1652CB9cc5aA6f";
await qb.append({blockNumber: 9221736});
await qb.append({blockNumber: 9221524, address: UNI_V2_ADDR});
await qb.append({blockNumber: 9221524, address: UNI_V2_ADDR, slot: 0});
await qb.append({blockNumber: 9221524, address: UNI_V2_ADDR, slot: 1});
The
append function will validate the value at the slot. An error will be thrown if you attempt to read from a slot at an account that has not yet been created. Please note that blockNumbers on Goerli are in a different range than those on Mainnet, and contracts may have been deployed on one network but not the other.Once you are done, call the
build method on the QueryBuilder to assemble your query in the correct format to be sent on-chain. This will result in two identifiers keccakQueryResponse and queryHash which are associated to the query on- and off-chain, respectively.const {keccakQueryResponse, queryHash, query} = await qb.build();
This format consists of three pieces:
keccakQueryResponse: A Merkle-ized commitment to thequeryused as a unique identifier.queryHash: A keccak256 hash of thequery.query: A complete specification of the query used as calldata.
The
sendQuery function in the AxiomV1Query contract allows users to trustlessly query historic on-chain data. Make sure you have ethers installed and configured before continuing. Then, build and send a query transaction using the output of
QueryBuilder in the previous step:const txResult = await axiomV1Query.sendQuery(
keccakQueryResponse,
<refundAddress>,
query,
{
value: ethers.parseEther("0.01"), // Goerli payment value
}
);
const txReceipt = await txResult.wait();
This query transaction includes a payment of 0.01 ETH to be collected upon query fulfillment. See Fees for more information about fees and refunds.
Last modified 21d ago