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ChainlinkClient.sol
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ChainlinkClient.sol
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// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
import {Chainlink} from "./Chainlink.sol";
import {ENSInterface} from "./interfaces/ENSInterface.sol";
import {LinkTokenInterface} from "./shared/interfaces/LinkTokenInterface.sol";
import {ChainlinkRequestInterface} from "./interfaces/ChainlinkRequestInterface.sol";
import {OperatorInterface} from "./interfaces/OperatorInterface.sol";
import {PointerInterface} from "./interfaces/PointerInterface.sol";
import {ENSResolver as ENSResolver_Chainlink} from "./vendor/ENSResolver.sol";
/**
* @title The ChainlinkClient contract
* @notice Contract writers can inherit this contract in order to create requests for the
* Chainlink network
*/
// solhint-disable gas-custom-errors
abstract contract ChainlinkClient {
using Chainlink for Chainlink.Request;
uint256 internal constant LINK_DIVISIBILITY = 10 ** 18;
uint256 private constant AMOUNT_OVERRIDE = 0;
address private constant SENDER_OVERRIDE = address(0);
uint256 private constant ORACLE_ARGS_VERSION = 1;
uint256 private constant OPERATOR_ARGS_VERSION = 2;
bytes32 private constant ENS_TOKEN_SUBNAME = keccak256("link");
bytes32 private constant ENS_ORACLE_SUBNAME = keccak256("oracle");
address private constant LINK_TOKEN_POINTER = 0xC89bD4E1632D3A43CB03AAAd5262cbe4038Bc571;
ENSInterface private s_ens;
bytes32 private s_ensNode;
LinkTokenInterface private s_link;
OperatorInterface private s_oracle;
uint256 private s_requestCount = 1;
mapping(bytes32 => address) private s_pendingRequests;
event ChainlinkRequested(bytes32 indexed id);
event ChainlinkFulfilled(bytes32 indexed id);
event ChainlinkCancelled(bytes32 indexed id);
/**
* @notice Creates a request that can hold additional parameters
* @param specId The Job Specification ID that the request will be created for
* @param callbackAddr address to operate the callback on
* @param callbackFunctionSignature function signature to use for the callback
* @return A Chainlink Request struct in memory
*/
function _buildChainlinkRequest(
bytes32 specId,
address callbackAddr,
bytes4 callbackFunctionSignature
) internal pure returns (Chainlink.Request memory) {
Chainlink.Request memory req;
return req._initialize(specId, callbackAddr, callbackFunctionSignature);
}
/**
* @notice Creates a request that can hold additional parameters
* @param specId The Job Specification ID that the request will be created for
* @param callbackFunctionSignature function signature to use for the callback
* @return A Chainlink Request struct in memory
*/
function _buildOperatorRequest(
bytes32 specId,
bytes4 callbackFunctionSignature
) internal view returns (Chainlink.Request memory) {
Chainlink.Request memory req;
return req._initialize(specId, address(this), callbackFunctionSignature);
}
/**
* @notice Creates a Chainlink request to the stored oracle address
* @dev Calls `chainlinkRequestTo` with the stored oracle address
* @param req The initialized Chainlink Request
* @param payment The amount of LINK to send for the request
* @return requestId The request ID
*/
function _sendChainlinkRequest(Chainlink.Request memory req, uint256 payment) internal returns (bytes32) {
return _sendChainlinkRequestTo(address(s_oracle), req, payment);
}
/**
* @notice Creates a Chainlink request to the specified oracle address
* @dev Generates and stores a request ID, increments the local nonce, and uses `transferAndCall` to
* send LINK which creates a request on the target oracle contract.
* Emits ChainlinkRequested event.
* @param oracleAddress The address of the oracle for the request
* @param req The initialized Chainlink Request
* @param payment The amount of LINK to send for the request
* @return requestId The request ID
*/
function _sendChainlinkRequestTo(
address oracleAddress,
Chainlink.Request memory req,
uint256 payment
) internal returns (bytes32 requestId) {
uint256 nonce = s_requestCount;
s_requestCount = nonce + 1;
bytes memory encodedRequest = abi.encodeWithSelector(
ChainlinkRequestInterface.oracleRequest.selector,
SENDER_OVERRIDE, // Sender value - overridden by onTokenTransfer by the requesting contract's address
AMOUNT_OVERRIDE, // Amount value - overridden by onTokenTransfer by the actual amount of LINK sent
req.id,
address(this),
req.callbackFunctionId,
nonce,
ORACLE_ARGS_VERSION,
req.buf.buf
);
return _rawRequest(oracleAddress, nonce, payment, encodedRequest);
}
/**
* @notice Creates a Chainlink request to the stored oracle address
* @dev This function supports multi-word response
* @dev Calls `sendOperatorRequestTo` with the stored oracle address
* @param req The initialized Chainlink Request
* @param payment The amount of LINK to send for the request
* @return requestId The request ID
*/
function _sendOperatorRequest(Chainlink.Request memory req, uint256 payment) internal returns (bytes32) {
return _sendOperatorRequestTo(address(s_oracle), req, payment);
}
/**
* @notice Creates a Chainlink request to the specified oracle address
* @dev This function supports multi-word response
* @dev Generates and stores a request ID, increments the local nonce, and uses `transferAndCall` to
* send LINK which creates a request on the target oracle contract.
* Emits ChainlinkRequested event.
* @param oracleAddress The address of the oracle for the request
* @param req The initialized Chainlink Request
* @param payment The amount of LINK to send for the request
* @return requestId The request ID
*/
function _sendOperatorRequestTo(
address oracleAddress,
Chainlink.Request memory req,
uint256 payment
) internal returns (bytes32 requestId) {
uint256 nonce = s_requestCount;
s_requestCount = nonce + 1;
bytes memory encodedRequest = abi.encodeWithSelector(
OperatorInterface.operatorRequest.selector,
SENDER_OVERRIDE, // Sender value - overridden by onTokenTransfer by the requesting contract's address
AMOUNT_OVERRIDE, // Amount value - overridden by onTokenTransfer by the actual amount of LINK sent
req.id,
req.callbackFunctionId,
nonce,
OPERATOR_ARGS_VERSION,
req.buf.buf
);
return _rawRequest(oracleAddress, nonce, payment, encodedRequest);
}
/**
* @notice Make a request to an oracle
* @param oracleAddress The address of the oracle for the request
* @param nonce used to generate the request ID
* @param payment The amount of LINK to send for the request
* @param encodedRequest data encoded for request type specific format
* @return requestId The request ID
*/
function _rawRequest(
address oracleAddress,
uint256 nonce,
uint256 payment,
bytes memory encodedRequest
) private returns (bytes32 requestId) {
requestId = keccak256(abi.encodePacked(this, nonce));
s_pendingRequests[requestId] = oracleAddress;
emit ChainlinkRequested(requestId);
require(s_link.transferAndCall(oracleAddress, payment, encodedRequest), "unable to transferAndCall to oracle");
return requestId;
}
/**
* @notice Allows a request to be cancelled if it has not been fulfilled
* @dev Requires keeping track of the expiration value emitted from the oracle contract.
* Deletes the request from the `pendingRequests` mapping.
* Emits ChainlinkCancelled event.
* @param requestId The request ID
* @param payment The amount of LINK sent for the request
* @param callbackFunc The callback function specified for the request
* @param expiration The time of the expiration for the request
*/
function _cancelChainlinkRequest(
bytes32 requestId,
uint256 payment,
bytes4 callbackFunc,
uint256 expiration
) internal {
OperatorInterface requested = OperatorInterface(s_pendingRequests[requestId]);
delete s_pendingRequests[requestId];
emit ChainlinkCancelled(requestId);
requested.cancelOracleRequest(requestId, payment, callbackFunc, expiration);
}
/**
* @notice the next request count to be used in generating a nonce
* @dev starts at 1 in order to ensure consistent gas cost
* @return returns the next request count to be used in a nonce
*/
function _getNextRequestCount() internal view returns (uint256) {
return s_requestCount;
}
/**
* @notice Sets the stored oracle address
* @param oracleAddress The address of the oracle contract
*/
function _setChainlinkOracle(address oracleAddress) internal {
s_oracle = OperatorInterface(oracleAddress);
}
/**
* @notice Sets the LINK token address
* @param linkAddress The address of the LINK token contract
*/
function _setChainlinkToken(address linkAddress) internal {
s_link = LinkTokenInterface(linkAddress);
}
/**
* @notice Sets the Chainlink token address for the public
* network as given by the Pointer contract
*/
function _setPublicChainlinkToken() internal {
_setChainlinkToken(PointerInterface(LINK_TOKEN_POINTER).getAddress());
}
/**
* @notice Retrieves the stored address of the LINK token
* @return The address of the LINK token
*/
function _chainlinkTokenAddress() internal view returns (address) {
return address(s_link);
}
/**
* @notice Retrieves the stored address of the oracle contract
* @return The address of the oracle contract
*/
function _chainlinkOracleAddress() internal view returns (address) {
return address(s_oracle);
}
/**
* @notice Allows for a request which was created on another contract to be fulfilled
* on this contract
* @param oracleAddress The address of the oracle contract that will fulfill the request
* @param requestId The request ID used for the response
*/
function _addChainlinkExternalRequest(
address oracleAddress,
bytes32 requestId
) internal notPendingRequest(requestId) {
s_pendingRequests[requestId] = oracleAddress;
}
/**
* @notice Sets the stored oracle and LINK token contracts with the addresses resolved by ENS
* @dev Accounts for subnodes having different resolvers
* @param ensAddress The address of the ENS contract
* @param node The ENS node hash
*/
function _useChainlinkWithENS(address ensAddress, bytes32 node) internal {
s_ens = ENSInterface(ensAddress);
s_ensNode = node;
bytes32 linkSubnode = keccak256(abi.encodePacked(s_ensNode, ENS_TOKEN_SUBNAME));
ENSResolver_Chainlink resolver = ENSResolver_Chainlink(s_ens.resolver(linkSubnode));
_setChainlinkToken(resolver.addr(linkSubnode));
_updateChainlinkOracleWithENS();
}
/**
* @notice Sets the stored oracle contract with the address resolved by ENS
* @dev This may be called on its own as long as `useChainlinkWithENS` has been called previously
*/
function _updateChainlinkOracleWithENS() internal {
bytes32 oracleSubnode = keccak256(abi.encodePacked(s_ensNode, ENS_ORACLE_SUBNAME));
ENSResolver_Chainlink resolver = ENSResolver_Chainlink(s_ens.resolver(oracleSubnode));
_setChainlinkOracle(resolver.addr(oracleSubnode));
}
/**
* @notice Ensures that the fulfillment is valid for this contract
* @dev Use if the contract developer prefers methods instead of modifiers for validation
* @param requestId The request ID for fulfillment
*/
function _validateChainlinkCallback(
bytes32 requestId
)
internal
recordChainlinkFulfillment(requestId) // solhint-disable-next-line no-empty-blocks
{}
/**
* @dev Reverts if the sender is not the oracle of the request.
* Emits ChainlinkFulfilled event.
* @param requestId The request ID for fulfillment
*/
modifier recordChainlinkFulfillment(bytes32 requestId) {
require(msg.sender == s_pendingRequests[requestId], "Source must be the oracle of the request");
delete s_pendingRequests[requestId];
emit ChainlinkFulfilled(requestId);
_;
}
/**
* @dev Reverts if the request is already pending
* @param requestId The request ID for fulfillment
*/
modifier notPendingRequest(bytes32 requestId) {
require(s_pendingRequests[requestId] == address(0), "Request is already pending");
_;
}
}