Onchain report verification (EVM chains)
Verify reports onchain
To verify data onchain on EVM chains, Streams Direct requires several Solidity interfaces.
The primary onchain interaction occurs between the IVerifierProxy interface and your protocol's client contract. Find the Verifier proxy address for each stream on the Stream Addresses page.
Interfaces
- IVerifierProxy
- IFeeManager
In the current code example for verifying reports onchain using Streams Direct, these interfaces are specified in the example itself. Imports for these interfaces will be available in the future.
Contract example to verify report data onchain
This contract example allows you to verify reports and pay the verification fee in LINK tokens. Your contract must have sufficient LINK tokens to pay for the verification fee. Learn how to fund your contract with LINK tokens.
// SPDX-License-Identifier: MIT
pragma solidity 0.8.19;
import {Common} from "@chainlink/contracts/src/v0.8/llo-feeds/libraries/Common.sol";
import {IVerifierFeeManager} from "@chainlink/contracts/src/v0.8/llo-feeds/v0.3.0/interfaces/IVerifierFeeManager.sol";
import {IERC20} from "@chainlink/contracts/src/v0.8/vendor/openzeppelin-solidity/v4.8.3/contracts/token/ERC20/IERC20.sol";
import {SafeERC20} from "@chainlink/contracts/src/v0.8/vendor/openzeppelin-solidity/v4.8.3/contracts/token/ERC20/utils/SafeERC20.sol";
using SafeERC20 for IERC20;
/**
* THIS IS AN EXAMPLE CONTRACT THAT USES UN-AUDITED CODE FOR DEMONSTRATION PURPOSES.
* DO NOT USE THIS CODE IN PRODUCTION.
*
* This contract can verify Chainlink Data Streams reports onchain and pay
* the verification fee in LINK (when required).
*
* - If `VerifierProxy.s_feeManager()` returns a non-zero address, the network
* expects you to interact with that FeeManager for every verification call:
* quote fees, approve the RewardManager, then call `verify()`.
*
* - If `s_feeManager()` returns the zero address, no FeeManager contract has
* been deployed on that chain. In that case there is nothing to quote or pay
* onchain, so the contract skips the fee logic entirely.
*
* The `if (address(feeManager) != address(0))` check below chooses the
* correct path automatically, making the same bytecode usable on any chain.
*/
// ────────────────────────────────────────────────────────────────────────────
// Interfaces
// ────────────────────────────────────────────────────────────────────────────
interface IVerifierProxy {
/**
* @notice Route a report to the correct verifier and (optionally) bill fees.
* @param payload Full report payload (header + signed report).
* @param parameterPayload ABI-encoded fee metadata.
*/
function verify(
bytes calldata payload,
bytes calldata parameterPayload
) external payable returns (bytes memory verifierResponse);
function verifyBulk(
bytes[] calldata payloads,
bytes calldata parameterPayload
) external payable returns (bytes[] memory verifiedReports);
function s_feeManager() external view returns (IVerifierFeeManager);
}
interface IFeeManager {
/**
* @return fee, reward, totalDiscount
*/
function getFeeAndReward(
address subscriber,
bytes memory unverifiedReport,
address quoteAddress
) external returns (Common.Asset memory, Common.Asset memory, uint256);
function i_linkAddress() external view returns (address);
function i_nativeAddress() external view returns (address);
function i_rewardManager() external view returns (address);
}
// ────────────────────────────────────────────────────────────────────────────
// Contract
// ────────────────────────────────────────────────────────────────────────────
/**
* @dev This contract implements functionality to verify Data Streams reports from
* the Data Streams API, with payment in LINK tokens.
*/
contract ClientReportsVerifier {
// ----------------- Errors -----------------
error NothingToWithdraw();
error NotOwner(address caller);
error InvalidReportVersion(uint16 version);
// ----------------- Report schemas -----------------
// More info: https://docs.chain.link/data-streams/reference/report-schema
/**
* @dev Data Streams report schema v3 (crypto streams).
* Prices, bids and asks use 8 or 18 decimals depending on the stream.
*/
struct ReportV3 {
bytes32 feedId;
uint32 validFromTimestamp;
uint32 observationsTimestamp;
uint192 nativeFee;
uint192 linkFee;
uint32 expiresAt;
int192 price;
int192 bid;
int192 ask;
}
/**
* @dev Data Streams report schema v4 (RWA streams).
*/
struct ReportV4 {
bytes32 feedId;
uint32 validFromTimestamp;
uint32 observationsTimestamp;
uint192 nativeFee;
uint192 linkFee;
uint32 expiresAt;
int192 price;
uint32 marketStatus;
}
// ----------------- Storage -----------------
IVerifierProxy public immutable i_verifierProxy;
address private immutable i_owner;
int192 public lastDecodedPrice;
// ----------------- Events -----------------
event DecodedPrice(int192 price);
// ----------------- Constructor / modifier -----------------
/**
* @param _verifierProxy Address of the VerifierProxy on the target network.
* Addresses: https://docs.chain.link/data-streams/crypto-streams
*/
constructor(address _verifierProxy) {
i_owner = msg.sender;
i_verifierProxy = IVerifierProxy(_verifierProxy);
}
modifier onlyOwner() {
if (msg.sender != i_owner) revert NotOwner(msg.sender);
_;
}
// ----------------- Public API -----------------
/**
* @notice Verify a Data Streams report (schema v3 or v4).
*
* @dev Steps:
* 1. Decode the unverified report to get `reportData`.
* 2. Read the first two bytes → schema version (`0x0003` or `0x0004`).
* - Revert if the version is unsupported.
* 3. Fee handling:
* - Query `s_feeManager()` on the proxy.
* – Non-zero → quote the fee, approve the RewardManager,
* ABI-encode the fee token address for `verify()`.
* – Zero → no FeeManager; skip quoting/approval and pass `""`.
* 4. Call `VerifierProxy.verify()`.
* 5. Decode the verified report into the correct struct and emit the price.
*
* @param unverifiedReport Full payload returned by Streams Direct.
* @custom:reverts InvalidReportVersion when schema ≠ v3/v4.
*/
function verifyReport(bytes memory unverifiedReport) external {
// ─── 1. & 2. Extract reportData and schema version ──
(, bytes memory reportData) = abi.decode(
unverifiedReport,
(bytes32[3], bytes)
);
uint16 reportVersion = (uint16(uint8(reportData[0])) << 8) |
uint16(uint8(reportData[1]));
if (reportVersion != 3 && reportVersion != 4)
revert InvalidReportVersion(reportVersion);
// ─── 3. Fee handling ──
IFeeManager feeManager = IFeeManager(
address(i_verifierProxy.s_feeManager())
);
bytes memory parameterPayload;
if (address(feeManager) != address(0)) {
// FeeManager exists — always quote & approve
address feeToken = feeManager.i_linkAddress();
(Common.Asset memory fee, , ) = feeManager.getFeeAndReward(
address(this),
reportData,
feeToken
);
IERC20(feeToken).approve(feeManager.i_rewardManager(), fee.amount);
parameterPayload = abi.encode(feeToken);
} else {
// No FeeManager deployed on this chain
parameterPayload = bytes("");
}
// ─── 4. Verify through the proxy ──
bytes memory verified = i_verifierProxy.verify(
unverifiedReport,
parameterPayload
);
// ─── 5. Decode & store price ──
if (reportVersion == 3) {
int192 price = abi.decode(verified, (ReportV3)).price;
lastDecodedPrice = price;
emit DecodedPrice(price);
} else {
int192 price = abi.decode(verified, (ReportV4)).price;
lastDecodedPrice = price;
emit DecodedPrice(price);
}
}
/**
* @notice Withdraw all balance of an ERC-20 token held by this contract.
* @param _beneficiary Address that receives the tokens.
* @param _token ERC-20 token address.
*/
function withdrawToken(
address _beneficiary,
address _token
) external onlyOwner {
uint256 amount = IERC20(_token).balanceOf(address(this));
if (amount == 0) revert NothingToWithdraw();
IERC20(_token).safeTransfer(_beneficiary, amount);
}
}