Eip20Kit.Swift is an extension to EvmKit.Swift that implements Eip20 token standard.
- Synchronization of EIP20 token balance and transactions
- Allowance management
- Reactive API for wallet
import EvmKit
import Eip20Kit
import HdWalletKit
let contractAddress = try EvmKit.Address(hex: "0x..token..contract..address..")
let evmKit = try Kit.instance(
address: try EvmKit.Address(hex: "0x..user..address.."),
chain: .ethereum,
rpcSource: .ethereumInfuraWebsocket(projectId: "...", projectSecret: "..."),
transactionSource: .ethereumEtherscan(apiKey: "..."),
walletId: "unique_wallet_id",
minLogLevel: .error
)
let eip20Kit = try Eip20Kit.Kit.instance(
evmKit: evmKit,
contractAddress: contractAddress
)
// Decorators are needed to detect transactions as `Eip20` transfer/approve transactions
Eip20Kit.Kit.addDecorators(to: evmKit)
// Eip20 transactions syncer is needed to pull Eip20 transfer transactions from Etherscan
Eip20Kit.Kit.addTransactionSyncer(to: evmKit)guard let balance = eip20Kit.balance else {
return
}
print("Balance: \(balance.description)")// Get Signer object
let seed = Mnemonic.seed(mnemonic: ["mnemonic", "words", ...])!
let signer = try Signer.instance(seed: seed, chain: .ethereum)
let to = try EvmKit.Address(hex: "0x..recipient..adress..here")
let amount = BigUInt("100000000000000000")
let gasPrice = GasPrice.legacy(gasPrice: 50_000_000_000)
// Construct TransactionData which calls a `Transfer` method of the EIP20 compatible smart contract
let transactionData = eip20Kit.transferTransactionData(to: to, value: amount)
// Estimate gas for the transaction
let estimateGasSingle = evmKit.estimateGas(transactionData: transactionData, gasPrice: gasPrice)
// Generate a raw transaction which is ready to be signed
let rawTransactionSingle = estimateGasSingle.flatMap { estimatedGasLimit in
evmKit.rawTransaction(transactionData: transactionData, gasPrice: gasPrice, gasLimit: estimatedGasLimit)
}
let sendSingle = rawTransactionSingle.flatMap { rawTransaction in
// Sign the transaction
let signature = try signer.signature(rawTransaction: rawTransaction)
// Send the transaction to RPC node
return evmKit.sendSingle(rawTransaction: rawTransaction, signature: signature)
}
let disposeBag = DisposeBag()
// This step is needed for Rx reactive code to run
sendSingle
.subscribe(
onSuccess: { fullTransaction in
// sendSingle returns FullTransaction object which contains transaction, and a transaction decoration
// Eip20Kit.Swift kit creates a OutgoingDecoration decoration for transfer method transaction
let transaction = fullTransaction.transaction
print("Transaction sent: \(transaction.hash.hs.hexString)")
guard let decoration = transaction.decoration as? OutgoingDecoration else {
return
}
print("To: \(decoration.to.eip55)")
print("Amount: \(decoration.value.description)")
}, onError: { error in
print("Send failed: \(error)")
}
)
.disposed(by: disposeBag)evmKit.transactionsSingle(tagQueries: [TransactionTagQuery(protocol: .eip20, contractAddress: contractAddress)])
.subscribe(
onSuccess: { fullTransactions in
for fullTransaction in fullTransactions {
let transaction = fullTransaction.transaction
print("Transaction hash: \(transaction.hash.hs.hexString)")
switch fullTransaction.decoration {
case let decoration as IncomingDecoration:
print("From: \(decoration.from.eip55)")
print("Amount: \(decoration.value.description)")
case let decoration as OutgoingDecoration:
print("To: \(decoration.to.eip55)")
print("Amount: \(decoration.value.description)")
default: ()
}
}
}, onError: { error in
print("Send failed: \(error)")
}
)
.disposed(by: disposeBag)- Xcode 10.0+
- Swift 5.5+
- iOS 11+
dependencies: [
.package(url: "https://github.com/horizontalsystems/Eip20Kit.Swift.git", .upToNextMajor(from: "1.0.0"))
]The Eip20Kit.Swift toolkit is open source and available under the terms of the MIT License.