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wormhole-nativeswap-example
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Add native relayer payment for exactIn swaps

This commit is contained in:
Drew 2022-07-01 17:52:56 +00:00
parent 330122eece
commit 162dd6ce9e
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GPG Key ID: 14D9F383FC9F839E
2 changed files with 40 additions and 32 deletions
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34
contracts/contracts/CrossChainSwapV2.sol
View File

@ -96,30 +96,31 @@ contract CrossChainSwapV2 {
"tokenOut must be wrapped native asset"
);
// pay relayer before attempting to do the swap
// reflect payment in second swap amount
IERC20 feeToken = IERC20(FEE_TOKEN_ADDRESS);
feeToken.safeTransfer(msg.sender, payload.relayerFee);
uint256 swapAmountLessFees = payload.swapAmount - payload.relayerFee;
// approve the router to spend tokens
TransferHelper.safeApprove(
uniPath[0],
address(SWAP_ROUTER),
swapAmountLessFees
payload.swapAmount
);
// try to execute the swap
try SWAP_ROUTER.swapExactTokensForTokens(
swapAmountLessFees,
payload.swapAmount,
payload.estimatedAmount,
uniPath,
address(this),
payload.deadline
) returns (uint256[] memory amounts) {
// calculate how much to pay the relayer in the native token
uint256 nativeRelayerFee = amounts[1] * payload.relayerFee / payload.swapAmount;
uint256 nativeAmountOut = amounts[1] - nativeRelayerFee;
// unwrap native and send to recipient
IWETH(WRAPPED_NATIVE).withdraw(amounts[1]);
payable(payload.recipientAddress).transfer(amounts[1]);
payable(payload.recipientAddress).transfer(nativeAmountOut);
/// pay the relayer in the native token
payable(msg.sender).transfer(nativeRelayerFee);
// used in UI to tell user they're getting
// their desired token
@ -127,15 +128,19 @@ contract CrossChainSwapV2 {
payload.recipientAddress,
uniPath[1],
msg.sender,
amounts[1],
nativeAmountOut,
1
);
return amounts;
} catch {
// pay relayer in the feeToken since the swap failed
IERC20 feeToken = IERC20(FEE_TOKEN_ADDRESS);
feeToken.safeTransfer(msg.sender, payload.relayerFee);
// swap failed - return feeToken to recipient
IERC20(FEE_TOKEN_ADDRESS).safeTransfer(
feeToken.safeTransfer(
payload.recipientAddress,
swapAmountLessFees
payload.swapAmount - payload.relayerFee
);
// used in UI to tell user they're getting
@ -144,7 +149,7 @@ contract CrossChainSwapV2 {
payload.recipientAddress,
uniPath[0],
msg.sender,
swapAmountLessFees,
payload.swapAmount - payload.relayerFee,
0
);
}
@ -176,8 +181,7 @@ contract CrossChainSwapV2 {
"tokenOut must be wrapped native asset"
);
// pay relayer before attempting to do the swap
// reflect payment in second swap amount
// pay the relayer in feeToken so that user gets desired exact amount out
IERC20 feeToken = IERC20(FEE_TOKEN_ADDRESS);
feeToken.safeTransfer(msg.sender, payload.relayerFee);
uint256 maxAmountInLessFees = payload.swapAmount - payload.relayerFee;

38
contracts/contracts/CrossChainSwapV3.sol
View File

@ -93,19 +93,13 @@ contract CrossChainSwapV3 {
require(
payload.path[1]==WRAPPED_NATIVE,
"tokenOut must be wrapped Native"
);
// pay relayer before attempting to do the swap
// reflect payment in second swap amount
IERC20 feeToken = IERC20(FEE_TOKEN_ADDRESS);
feeToken.safeTransfer(msg.sender, payload.relayerFee);
uint256 swapAmountLessFees = payload.swapAmount - payload.relayerFee;
);
// approve the router to spend tokens
TransferHelper.safeApprove(
payload.path[0],
address(SWAP_ROUTER),
swapAmountLessFees
payload.swapAmount
);
// set swap options with user params
@ -116,16 +110,23 @@ contract CrossChainSwapV3 {
fee: payload.poolFee,
recipient: address(this),
deadline: payload.deadline,
amountIn: swapAmountLessFees,
amountIn: payload.swapAmount,
amountOutMinimum: payload.estimatedAmount,
sqrtPriceLimitX96: 0
});
// try to execute the swap
try SWAP_ROUTER.exactInputSingle(params) returns (uint256 amountOut) {
// calculate how much to pay the relayer in the native token
uint256 nativeRelayerFee = amountOut * payload.relayerFee / payload.swapAmount;
uint256 nativeAmountOut = amountOut - nativeRelayerFee;
// unwrap native and send to recipient
IWETH(WRAPPED_NATIVE).withdraw(amountOut);
payable(payload.recipientAddress).transfer(amountOut);
payable(payload.recipientAddress).transfer(nativeAmountOut);
/// pay the relayer in the native token
payable(msg.sender).transfer(nativeRelayerFee);
// used in UI to tell user they're getting
// their desired token
@ -133,15 +134,19 @@ contract CrossChainSwapV3 {
payload.recipientAddress,
payload.path[1],
msg.sender,
amountOut,
nativeAmountOut,
1
);
return amountOut;
} catch {
// swap failed - return feeToken to recipient
IERC20(FEE_TOKEN_ADDRESS).safeTransfer(
// pay relayer in the feeToken since the swap failed
IERC20 feeToken = IERC20(FEE_TOKEN_ADDRESS);
feeToken.safeTransfer(msg.sender, payload.relayerFee);
// swap failed - return feeToken (less relayer fees) to recipient
feeToken.safeTransfer(
payload.recipientAddress,
swapAmountLessFees
payload.swapAmount - payload.relayerFee
);
// used in UI to tell user they're getting
@ -150,7 +155,7 @@ contract CrossChainSwapV3 {
payload.recipientAddress,
payload.path[0],
msg.sender,
swapAmountLessFees,
payload.swapAmount - payload.relayerFee,
0
);
}
@ -177,8 +182,7 @@ contract CrossChainSwapV3 {
"tokenOut must be wrapped native asset"
);
// pay relayer before attempting to do the swap
// reflect payment in second swap amount
// pay the relayer in feeToken so that user gets desired exact amount out
IERC20 feeToken = IERC20(FEE_TOKEN_ADDRESS);
feeToken.safeTransfer(msg.sender, payload.relayerFee);
uint256 maxAmountInLessFees = payload.swapAmount - payload.relayerFee;