feat: ethereum fee proxy with transfer exact eth amount (#591)

RequestNetwork · Sep 24, 2021 · eb08b85 · eb08b85
1 parent 8607627
commit eb08b85
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Showing 3 changed files with 93 additions and 5 deletions.
diff --git a/packages/smart-contracts/src/contracts/EthereumFeeProxy.sol b/packages/smart-contracts/src/contracts/EthereumFeeProxy.sol
@@ -1,11 +1,13 @@
 // SPDX-License-Identifier: MIT
 pragma solidity ^0.8.0;
 
+import "@openzeppelin/contracts/security/ReentrancyGuard.sol";
+
 /**
  * @title EthereumFeeProxy
  * @notice This contract performs an Ethereum transfer with a Fee sent to a third address and stores a reference
  */
-contract EthereumFeeProxy {
+contract EthereumFeeProxy is ReentrancyGuard{
   // Event to declare a transfer with a reference
   event TransferWithReferenceAndFee(
     address to,
@@ -15,12 +17,12 @@ contract EthereumFeeProxy {
     address feeAddress
   );
 
-
   // Fallback function returns funds to the sender
   receive() external payable {
     revert("not payable receive");
   }
 
+
   /**
   * @notice Performs an Ethereum transfer with a reference
   * @param _to Transfer recipient
@@ -37,8 +39,40 @@ contract EthereumFeeProxy {
     external
     payable
   {
-    _to.transfer(msg.value - _feeAmount);
+    transferExactEthWithReferenceAndFee(
+      _to,
+      msg.value - _feeAmount,
+      _paymentReference,
+      _feeAmount,
+      _feeAddress
+    );
+  }
+
+
+  /**
+  * @notice Performs an Ethereum transfer with a reference with an exact amount of eth
+  * @param _to Transfer recipient
+  * @param _amount Amount to transfer
+  * @param _paymentReference Reference of the payment related
+  * @param _feeAmount The amount of the payment fee (part of the msg.value)
+  * @param _feeAddress The fee recipient
+  */
+  function transferExactEthWithReferenceAndFee(
+    address payable _to,
+    uint256 _amount,
+    bytes calldata _paymentReference,
+    uint256 _feeAmount,
+    address payable _feeAddress
+  )
+    nonReentrant
+    public
+    payable
+  {
+    _to.transfer(_amount);
     _feeAddress.transfer(_feeAmount);
-    emit TransferWithReferenceAndFee(_to, msg.value - _feeAmount, _paymentReference, _feeAmount, _feeAddress);
+    // transfer the remaining ethers to the sender
+    payable(msg.sender).transfer(msg.value - _amount - _feeAmount);
+
+    emit TransferWithReferenceAndFee(_to, _amount, _paymentReference, _feeAmount, _feeAddress);
   }
-}
+}
diff --git a/packages/smart-contracts/src/lib/artifacts/EthereumFeeProxy/0.1.0.json b/packages/smart-contracts/src/lib/artifacts/EthereumFeeProxy/0.1.0.json
@@ -37,6 +37,39 @@
       "name": "TransferWithReferenceAndFee",
       "type": "event"
     },
+    {
+      "inputs": [
+        {
+          "internalType": "address payable",
+          "name": "_to",
+          "type": "address"
+        },
+        {
+          "internalType": "uint256",
+          "name": "_amount",
+          "type": "uint256"
+        },
+        {
+          "internalType": "bytes",
+          "name": "_paymentReference",
+          "type": "bytes"
+        },
+        {
+          "internalType": "uint256",
+          "name": "_feeAmount",
+          "type": "uint256"
+        },
+        {
+          "internalType": "address payable",
+          "name": "_feeAddress",
+          "type": "address"
+        }
+      ],
+      "name": "transferExactEthWithReferenceAndFee",
+      "outputs": [],
+      "stateMutability": "payable",
+      "type": "function"
+    },
     {
       "inputs": [
         {

diff --git a/packages/smart-contracts/test/contracts/EthereumFeeProxy.test.ts b/packages/smart-contracts/test/contracts/EthereumFeeProxy.test.ts
@@ -45,6 +45,27 @@ describe('contract: EthereumFeeProxy', () => {
     expect(contractBalance.toString()).to.equals("0");
   });
 
+  it('allows to pays exact eth with a reference with extra msg.value', async () => {
+    const toOldBalance = await provider.getBalance(to);
+    const feeAddressOldBalance = await provider.getBalance(feeAddress);
+
+    await expect(
+      ethFeeProxy.transferExactEthWithReferenceAndFee(to, amount, referenceExample, feeAmount, feeAddress, {
+        value: amount.add(feeAmount).add('10000'),
+      }),
+    ).to.emit(ethFeeProxy, 'TransferWithReferenceAndFee')
+      .withArgs(to, amount.toString(), ethers.utils.keccak256(referenceExample), feeAmount.toString(), feeAddress);
+
+      const toNewBalance = await provider.getBalance(to);
+      const feeAddressNewBalance = await provider.getBalance(feeAddress);
+      const contractBalance = await provider.getBalance(ethFeeProxy.address);
+
+    // Check balance changes
+    expect(toNewBalance.toString()).to.equals(toOldBalance.add(amount).toString());
+    expect(feeAddressNewBalance.toString()).to.equals(feeAddressOldBalance.add(feeAmount).toString());
+    expect(contractBalance.toString()).to.equals("0");
+  });
+
   it('cannot transfer if msg.value is too low', async () => {
     await expect(
         ethFeeProxy.transferWithReferenceAndFee(to, referenceExample, amount, feeAddress, {