📂 dApp Developers

# dataFeedIdToReaderToWhitelistStatus()

Table of Contents

For on-chain smart contracts, the function dataFeedIdToReaderToWhitelistStatus() (opens new window) returns read access information with the expirationTimestamp and indefiniteWhitelistCount of a reader for the specified dAPI data feed.

The reader will not be able to read the dAPI data feed past the expirationTimestamp (assuming their indefiniteWhitelistCount is 0 ). If the indefiniteWhitelistCount is greater than 0 , the reader will be able to read the data feed indefinitely (regardless of the value of expirationTimestamp).

# Example Usage

// SPDX-License-Identifier: MIT
pragma solidity 0.8.9;
import "@api3/airnode-protocol-v1/contracts/dapis/interfaces/IDapiServer.sol";
contract mySmartContract {
  function myReadable(
    address _dapiServerContractAddress,
    bytes32 _datafeedId
  ) external {
    uint64 expirationTimestamp;
    uint192 indefiniteWhitelistCount;
    // Calling the DapiServer for reader status
    // where "this" is the contract address of this contract (myReadable).
    (expirationTimestamp, indefiniteWhitelistCount) =
      IDapiServer(_dapiServerContractAddress).dataFeedIdToReaderToWhitelistStatus(_datafeedId, address(this));
  }
}
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# Parameters

dataFeedIdToReaderToWhitelistStatus(bytes32 datafeedId, address reader)

  • bytes32 datafeedId - The ID of a dAPI, Beacon, or Beacon set.
  • address reader - The address to verify such as the reader's smart contract address or another address.

# Using a dapiName for the datafeedId parameter

If you want to check the status using a dapiName, first encode the dapiName to bytes32 and calculate the off-chain hash of the encodedDapiName as shown below. Then pass the value of dapiNameHash as _datafeedId in the code example above. Try it in the ethers playground (opens new window).

// First encode the dapiName (such as AVAX/USD) to bytes32
encodedDapiName = ethers.utils.formatBytes32String("AVAX/USD");
// encodedDapiName now equals
// 0x415641582f555344000000000000000000000000000000000000000000000000
// Then calculate the off-chain hash
dapiNameHash = ethers.utils.solidityKeccak256(['bytes32'], [encodedDapiName]);
// dapiNameHash now equals
// 0xcc06defee290c6e46f55823e39eb14024b06d4a6c7a0b6bf8b1f1e229c389b9c
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# Returns

  • expirationTimestamp - Timestamp at which the whitelisting of the reader will expire.

  • indefiniteWhitelistCount - Number of times reader was whitelisted indefinitely for dataFeedId.

Last Updated: 12/20/2022, 7:23:07 AM