Add from, publicKey and unsignedMessage recovery functions to Ethereu…

…mSignedMessage
Boilertalk · Apr 30, 2024 · 8d771f1 · 8d771f1
1 parent 9c362d2
commit 8d771f1
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diff --git a/Sources/Core/Transaction/EthereumTransaction.swift b/Sources/Core/Transaction/EthereumTransaction.swift
@@ -712,3 +712,61 @@ extension EthereumSignedTransaction: Hashable {
         hasher.combine(transactionType)
     }
 }
+
+extension EthereumSignedTransaction {
+
+    public func from() throws -> EthereumAddress {
+        return try publicKey().address
+    }
+
+    public func publicKey() throws -> EthereumPublicKey {
+        let messageToSign = try self.unsignedMessage()
+        var recId: BigUInt
+        if v.quantity >= BigUInt(35) + (BigUInt(2) * chainId.quantity) {
+            recId = v.quantity - BigUInt(35) - (BigUInt(2) * chainId.quantity)
+        } else {
+            if v.quantity >= 27 {
+                recId = v.quantity - 27
+            } else {
+                recId = v.quantity
+            }
+        }
+        return try EthereumPublicKey(message: messageToSign, v: EthereumQuantity(quantity: recId), r: self.r, s: self.s)
+    }
+
+    private func unsignedMessage() throws -> Bytes {
+        let rlpEncoder = RLPEncoder()
+        let rlp = self.rlp()
+
+        if let arr = rlp.array{
+
+            if self.transactionType == .legacy {
+                let legacyrlp = RLPItem(
+                    nonce: self.nonce,
+                    gasPrice: self.gasPrice,
+                    gasLimit: self.gasLimit,
+                    to: self.to,
+                    value: self.value,
+                    data: self.data,
+                    v: self.chainId,
+                    r: 0,
+                    s: 0
+                )
+                let rawRlp = try RLPEncoder().encode(legacyrlp)
+                return rawRlp
+            } else if self.transactionType == .eip1559 {
+                let unsignedRlp = Array(arr[0..<(arr.count - 3)])
+                var messageToSign = Bytes()
+                let unsignedRlpBytes = try rlpEncoder.encode(RLPItem.array(unsignedRlp))
+                messageToSign.append(0x02)
+                messageToSign.append(contentsOf: unsignedRlpBytes)
+                return messageToSign
+            } else {
+                throw Error.transactionInvalid
+            }
+        } else {
+            throw Error.rlpItemInvalid
+        }
+    }
+
+}
diff --git a/Tests/Web3Tests/TransactionTests/TransactionTests.swift b/Tests/Web3Tests/TransactionTests/TransactionTests.swift
@@ -255,6 +255,33 @@ class TransactionTests: QuickSpec {
                     expect(extendedSignature == signedExtTx) == true
                 }
             }
+            context("Recover sender of Tx") {
+
+                // Modern tx
+
+                let rawExtTx = try? EthereumData(ethereumValue:  "0x02f8b40183879f6a84773594008517bfac7c0083032918943845badade8e6dff049820680d1f14bd3903a5d080b844a9059cbb000000000000000000000000566586bba243e683256cd4bef168813e42df9d6400000000000000000000000000000000000000000000003147d6c40e7e078000c001a08753897821b034540cb14d2aa0dafa880c9017831d633ff9da498cf0369d061ca016ad20c8c2aa12edcb8ab7fd8ff0ff980d65fe42d5859a8688ee92da36b479d6")
+
+                let signedExtTx = try! EthereumSignedTransaction(rawTx: rawExtTx!)
+                let extFrom = try! signedExtTx.from()
+                let expectedExtFrom = try! EthereumAddress(hex: "0xDFd5293D8e347dFe59E90eFd55b2956a1343963d", eip55: true)
+
+                it("should equal the extendedTx") {
+                    expect(extFrom == expectedExtFrom) == true
+                }
+
+                // Legacy tx
+
+                let rawTx = try? EthereumData(ethereumValue: "0xf8aa41850336f420fc830160429484018071282d4b2996272659d9c01cb08dd7327f80b844a9059cbb00000000000000000000000025b2ad0f7c48390278a39d58efeb94056fc49f1c000000000000000000000000000000000000000000000006e04233f855ff21a025a055b539fae05d8a8a19614e422fe8bc7f3ea9e49d9e613172f05fb7d584adb099a0124ce216d52a345a5293765065c3689d6134c92d42374604836c4cc8336cec42")
+
+                let legacyTx = try! EthereumSignedTransaction(rawTx: rawTx!)
+                let legacyFrom = try! legacyTx.from()
+                let expectedLegacyFrom = try! EthereumAddress(hex: "0x096C84037baA375749479b8bE002A11d11aa9a5a", eip55: true)
+
+                it("should be equal for legacy tx") {
+                    expect(legacyFrom == expectedLegacyFrom) == true
+                }
+
+            }
         }
     }
 }