EthereumKit-iOS
EthereumKit-iOS is a native(Swift), secure, reactive and extensible Ethereum client toolkit for iOS platform. It can be used by ETH/Erc20 wallet or by dapp client for any kind of interactions with Ethereum blockchain.
Features
- Ethereum wallet support, including internal Ether transfer transactions
- Support for ERC20 token standard
- Uniswap DEX support
- Reactive-functional API
- Implementation of Ethereum's JSON-RPC client API over HTTP or WebSocket
- Support for Infura
- Support for Etherscan
EthereumKit.swift
- Sync account state/balance
- Sync/Send/Receive Ethereum transactions
- Internal transactions retrieved from Etherscan
- Reactive API for Smart Contracts (Erc20Kit.swift and UniswapKit.swift use EthereumKit.swift for interactions with the blockchain)
- Reactive API for wallet
- Restore with mnemonic phrase
Erc20Kit.swift
- Sync balance
- Sync/Send/Receive Erc20 token transactions
- Allowance management
- Incoming Erc20 token transactions retrieved from Etherscan
- Reactive API for wallet
UniswapKit.swift
Supports following settings:
- Price Impact
- Deadline
- Recipient
- Fee on Transfer
Usage
Initialization
First you need to initialize an EthereumKit.Kit instance
import EthereumKit
let ethereumKit = try! Kit.instance(
words: ["word1", ... , "word12"],
syncMode: .api,
networkType: .ropsten,
rpcApi: .infuraWebSocket(id: "", secret: ""),
etherscanApiKey: "",
walletId: "walletId",
minLogLevel: .error
)
syncMode
parameter
.api
: Uses RPC.spv
: Ethereum light client. Not supported currently.geth
: Geth client. Not supported currently
networkfkType
parameter
.mainNet
.ropsten
.kovan
rpcApi
parameter
.infuraWebSocket(id: "", secret: "")
: RPC over HTTP.infura(id: "", secret: """)
: RPC over WebSocket
Additional parameters:
minLogLevel
: Can be configured for debug purposes if required.
Starting and Stopping
EthereumKit.Kit instance requires to be started with start
command
ethereumKit.start()
ethereumKit.stop()
Getting wallet data
You can get account state, lastBlockHeight, syncState, transactionsSyncState and some others synchronously
guard let state = ethereumKit.accountState else {
return
}
state.balance // 2937096768
state.nonce // 10
ethereumKit.lastBlockHeight // 10000000
You also can subscribe to Rx observables of those and some others
ethereumKit.accountStateObservable.subscribe(onNext: { state in print("balance: \(state.balance); nonce: \(state.nonce)") })
ethereumKit.lastBlockHeightObservable.subscribe(onNext: { height in print(height) })
ethereumKit.syncStateObservable.subscribe(onNext: { state in print(state) })
ethereumKit.transactionsSyncStateObservable.subscribe(onNext: { state in print(state) })
// Subscribe to all Ethereum transactions synced by the kit
ethereumKit.allTransactionsObservable.subscribe(onNext: { transactions in print(transactions.count) })
// Subscribe to Ether transactions
ethereumKit.etherTransactionsObservable.subscribe(onNext: { transactions in print(transactions.count) })
Send Transaction
let decimalAmount: Decimal = 0.1
let amount = BigUInt(decimalAmount.roundedString(decimal: decimal))!
let address = Address(hex: "0x73eb56f175916bd17b97379c1fdb5af1b6a82c84")!
ethereumKit
.sendSingle(address: address, value: amount, gasPrice: 50_000_000_000, gasLimit: 1_000_000_000_000)
.subscribe(onSuccess: { transaction in
print(transaction.transaction.hash.hex) // sendSingle returns FullTransaction object which contains transaction, receiptWithLogs and internalTransactions
})
Estimate Gas Limit
let decimalAmount: Decimal = 0.1
let amount = BigUInt(decimalAmount.roundedString(decimal: decimal))!
let address = Address(hex: "0x73eb56f175916bd17b97379c1fdb5af1b6a82c84")!
ethereumKit
.estimateGas(to: address, amount: amount, gasPrice: 50_000_000_000)
.subscribe(onSuccess: { gasLimit in
print(gasLimit)
})
Send Erc20 Transaction
import EthereumKit
import Erc20Kit
let decimalAmount: Decimal = 0.1
let amount = BigUInt(decimalAmount.roundedString(decimal: decimal))!
let address = Address(hex: "0x73eb56f175916bd17b97379c1fdb5af1b6a82c84")!
let erc20Kit = Erc20Kit.Kit.instance(ethereumKit: ethereumKit, contractAddress: "contract address of token")
let transactionData = erc20Kit.transferTransactionData(to: address, value: amount)
ethereumKit
.sendSingle(transactionData: transactionData, gasPrice: 50_000_000_000, gasLimit: 1_000_000_000_000)
.subscribe(onSuccess: { [weak self] _ in})
Send Uniswap swap transaction
import EthereumKit
import UniswapKit
import Erc20Kit
let uniswapKit = UniswapKit.Kit.instance(ethereumKit: ethereumKit)
let tokenIn = uniswapKit.etherToken
let tokenOut = uniswapKit.token(try! Address(hex: "0xad6d458402f60fd3bd25163575031acdce07538d"), decimal: 18)
let amount: Decimal = 0.1
uniswapKit
.swapDataSingle(tokenIn: tokenIn, tokenOut: tokenOut)
.flatMap { swapData in
let tradeData = try! uniswapKit.bestTradeExactIn(swapData: swapData, amountIn: amount)
let transactionData = try! uniswapKit.transactionData(tradeData: tradeData)
return ethereumKit.sendSingle(transactionData: transactionData, gasPrice: 50_000_000_000, gasLimit: 1_000_000_000_000)
}
.subscribe(onSuccess: { [weak self] _ in})
Extending
Add transaction syncer
Some smart contracts store some information concerning your address, which you can't retrieve in a standard way over RPC. If you have an external API to get them from, you can create a custom syncer and add it to EthereumKit. It will sync all the transactions your syncer gives.
Erc20TransactionSyncer is a good example of this. It gets token transfer transactions from Etherscan and feeds EthereumKit syncer with them. It is added to EthereumKit as following:
let transactionSyncer = Erc20TransactionSyncer(...)
ethereumKit.add(syncer: transactionSyncer)
Smart contract call
In order to make a call to any smart contract, you can use ethereumKit.sendSingle(transactionData:,gasPrice:,gasLimit:)
method. You need to create an instance of TransactionData
object. Currently, we don't have an ABI or source code parser. Please, look in Erc20Kit.swift and UniswapKit.swift to see how TransactionData
object is formed.
Prerequisites
- Xcode 10.0+
- Swift 5+
- iOS 11+
Installation
CocoaPods
CocoaPods is a dependency manager for Cocoa projects. You can install it with the following command:
$ gem install cocoapods
CocoaPods 1.5.0+ is required to build EthereumKit.
To integrate EthereumKit into your Xcode project using CocoaPods, specify it in your Podfile
:
source 'https://github.com/CocoaPods/Specs.git'
platform :ios, '10.0'
use_frameworks!
target '<Your Target Name>' do
pod 'EthereumKit.swift'
pod 'Erc20.swift'
pod 'UniswapKit.swift'
end
Then, run the following command:
$ pod install
Example Project
All features of the library are used in example project. It can be referred as a starting point for usage of the library.
Dependencies
- HSHDWalletKit - HD Wallet related features, mnemonic phrase generation.
- OpenSslKit.swift - Crypto functions required for working with blockchain.
- Secp256k1Kit.swift - Crypto functions required for working with blockchain.
- HsToolKit.swift - Helpers library from HorizontalSystems
- RxSwift
- BigInt
- GRDB.swift
- Starscream
License
The EthereumKit-iOS
toolkit is open source and available under the terms of the MIT License.