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ICON Developer Portal

ICON Network is a decentralized smart contract protocol based on ‘loopchain’, a high-performance blockchain engine. The ICON Network aims to remove barriers among different blockchains and allow them to exchange values without intermediaries. By realizing this goal, ICON will realize the mass adoption of blockchain technology and Hyperconnect the World.

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Swift API Reference

The source code is found on GitHub at https://github.com/icon-project/ICONKit

ICON supports SDK for 3rd party or user services development. You can integrate ICON SDK for your project and utilize the ICON’s functionality.
This document provides you with information about API specification.

class ICONService

ICONService is a class which provides APIs to communicate with ICON nodes. It enables you to easily use ICON JSON-RPC APIs (version 3). All methods of IconService returns a Request<T, ICError> instance.

Query Execution

Request are executed as synchronized and asynchronized.

Synchronized execution

To execute the request synchronously, you need to run execute() function of Request.

public func execute() -> Result<T, ICError>

Returns

Result<T, ICError>

Example

// Synchronized request execution
let response = iconService.getLastBlock().execute()

switch response {
case .success(let block):
    print(block)
case .failure(let error):
    print(error.errorDescription)
}

Asynchronized execution

To execute the request asynchronously, you need to run async() function of Request.

public func async(_ completion: @escaping (Result<T, ICError>) -> Void)

Returns

async() is a closure. Passing Result<T, ICError>.

Example

// Asynchronized request execution
iconService.getLastBlock().async { (result) in
    switch result {
    case .success(let block):
      print(block)
    case .failure(let error):
      print(err.errorDescription)
    }
}

Transaction Execution

Transaction class is used to make a transaction instance. There are 3 types of Transaction class.

ClassDescription
TransactionA class for Transaction instance which is for sending ICX.
CallTransactionA class for CallTransaction instance which is for SCORE function call. CallTransaction extends Transaction class.
MessageTransactionA class for MessageTransaction instance which is for transfer message. Extends Transaction class.

Request is executed as Synchronized or Asynchronized like a querying request.

Example

// Synchronized request
let response = iconService.sendTransaction(signedTransaction: signed).execute()

switch response {
case .success(let result): // result == String
    print(result)
case .error(let error):
    print(error)
}

// Asynchronized request
let request = iconService.sendTransaction(signedTransaction: signed)
request.async { (result) in
    switch result {
    case .success(let result): // result == String
        print(result)
    case .failure(let error):
        print(error)
    }
}

Initialize

init(provider: String, nid: String)

Parameters

ParameterTypeDescription
providerStringICON node url.
nidStringNetwork ID.

For more details of node URL and network id, see ICON Network document.

Example

// ICON Mainnet
let iconService = ICONService(provider: "https://ctz.solidwallet.io/api/v3", nid: "0x1")

func getLastBlock

Get the last block information.

func getLastBlock() -> Request<Response.Block>

Parameters

None

Returns

Request - Request instance for icx_getLastBlock JSON-RPC API request. If the execution is successful, returns Result<Response.Block, ICError>.

Example

// Returns last block
let response = iconService.getLastBlock().execute()

switch response {
case .success(let result): // result == Response.Block
    print(result)
case .error(let error):
    print(error)
}

func getBlock

Get the block information.

// Get block information by height.
func getBlock(height: UInt64) -> Request<Response.Block>

// Get block information by hash.
func getBlock(hash: String) -> Request<Response.Block>

Parameters

ParameterTypeDescription
heightUInt64Height value of block
hashStringHash value of block

Returns

Request - Request instance for icx_getBlockByHeight | icx_getBlockByHash. If the execution is successful, returns Result<Response.Block, ICError>.

Example

// Returns block information by block height
let heightBlock = iconService.getBlock(height: 10532).execute()

// Returns block information by block hash
let hashBlock = iconService.getBlock(hash: "0xdb310dd653b2573fd673ccc7489477a0b697333f77b3cb34a940db67b994fd95").execute()

switch heightBlock {
case .success(let block): // result == Response.Block
    print(block)
case .error(let error):
    print(error)
}

func call

Calls an external function of SCORE API.

func call<T>(_ call: Call<T>) -> Request<T>

Parameters

ParameterTypeDescription
callCallan instance of Call class.

Returns

Request<T> - Request instance for icx_call JSON-RPC request. If the execution is successful, returns Result<T, ICError>.

Example

In Call generic value, input the type of function call. The generic value should follow Codable protocol.

For example, the type of SCORE function call is String, input String like this.

// Create Call instance 
let call = Call<String>(from: wallet.address, to: "cxf9148db4f8ec78823a50cb06c4fed83660af38d0", method: "tokenOwner", params: nil)

let request: Request<String> = iconService.call(call)
let response: Result<String, ICError> = request.execute()

switch response {
case .success(let owner):
     print(owner) // hx70b591822468415e86fb9ba1354214902ea76196
case .failure(let error):
    print(error)
}

If SCORE call result is hex String, you can choice return types String or BigUInt.

Using Call<String>, return an original hex String value.

Using Call<BigUInt> return converted BigUInt value.

let ownerAddress: String = "hx07abc7a5b8a4941fc0b6930c88b462995acf929b"
let scoreAddress: String = "cxf9148db4f8ec78823a50cb06c4fed83660af38d0"

// Using `String`. Return hex String.
let call = Call<String>(from: ownerAddress, to: scoreAddress, method: "balanceOf", params: ["_owner": ownerAddress])
let request: Request<String> = iconService.call(call)
let response: Result<String, ICError> = request.execute()

switch response {
case .success(let balance):
     print("balance: \(balance)") // "balance: 0x11e468ef422cc60031ef"
case .failure(let error):
    print(error)
}


// Using `BigUInt`. Return BigUInt.
let call = Call<BigUInt>(from: ownerAddress, to: scoreAddress, method: "balanceOf", params: ["_owner": ownerAddress])
let request: Request<BigUInt> = iconService.call(call)
let response: Result<BigUInt, ICError> = request.execute()

switch response {
case .success(let balance):
     print("balance: \(balance)") // "balance: 84493649192649192649199"
case .failure(let error):
    print(error)
}

func getBalance

Get the balance of the address.

func getBalance(address: String) -> Request<BigUInt>

Parameters

ParameterTypeDescription
addressStringAn EOA Address

Returns

Request - Request instance for icx_getBalance JSON-RPC API request. If the execution is successful, returns Result<BigUInt, ICError>.

Example

// Returns the balance of specific address
let response = iconService.getBalance(address: "hx9d8a8376e7db9f00478feb9a46f44f0d051aab57").execute()

switch response {
case .success(let result): // result == BigUInt
    print(result)
case .error(let error):
    print(error)
}

func getScoreAPI

Get the SCORE API list.

func getScoreAPI(scoreAddress: String) -> Request<[Response.ScoreAPI]>

Parameters

ParameterTypeDescription
scoreAddressStringA SCORE address

Returns

Request - Request instance for icx_getScoreApi JSON-RPC API request. If the execution is successful, returns Result<[Response.ScoreAPI], ICError>.

Example

// Returns the SCORE API list
let response = iconService.getScoreAPI(scoreAddress: "cx0000000000000000000000000000000000000001").execute()

switch response {
case .success(let result): // result == [Response.ScoreAPI]
    print(result)
case .error(let error):
    print(error)
}

func getTotalSupply

get the total number of issued coins.

func getTotalSupply() -> Request<BigUInt>

Parameters

None

Returns

Request - Request instance for icx_getTotalSupply JSON-RPC API request. If the execution is successful, returns Result<BigUInt, ICError>.

Example

// Returns total value of issued coins
let response = iconService.getTotalSupply().execute()

switch response {
case .success(let result): // result == BigUInt
    print(result)
case .error(let error):
    print(error)
}

func getTransaction

Get the transaction information.

func getTransaction(hash: String) -> Request<Response.TransactionByHashResult>

Parameters

ParameterTypeDescription
hashStringHash value of transaction

Returns

Request - Request instnace for icx_getTransactionByHash JSON-RPC API request. If the execution is successful, returns Result<Response.TransactionByHashResult, ICError>.

Example

// Returns transaction information
let response = iconService.getTransaction(hash: "0xb903239f8543d04b5dc1ba6579132b143087c68db1b2168786408fcbce568238").execute()

switch response {
case .success(let result): // result == Response.TransactionByHashResult
    print(result)
case .error(let error):
    print(error)
}

func getTransactionResult

Get the transaction result information.

func getTransactionResult(hash: String) -> Request<Response.TransactionResult>

Parameters

ParameterTypeDescription
hashStringA transaction hash.

Returns

Request - Request instance for icx_getTransactionResult JSON-RPC API request. If the execution is successful, returns Result<Response.TransactionResult, ICError>.

Example

// Returns transaction result information
let response = iconService.getTransactionResult(hash: "0xb903239f8543d04b5dc1ba6579132b143087c68db1b2168786408fcbce568238").execute()

switch response {
case .success(let result): // result == Response.TransactionResult
    print(result)
case .error(let error):
    print(error)
}

func sendTransaction

Send a transaction that changes the state of address. Request is executed as Synchronized or Asynchronized like a querying request.

func sendTransaction(signedTransaction: SignedTransaction) -> Request<String>

Parameters

ParameterTypeDescription
signedTransactionSignedTransactionan instance of SignedTransaction class.

Returns

Request - Request instance for icx_sendTransaction JSON-RPC request. If the execution is successful, returns Result<String, ICError>.

Example

// Synchronized request
let response = iconService.sendTransaction(signedTransaction: signed).execute()

switch response {
case .success(let result): // result == String
    print(result)
case .error(let error):
    print(error)
}

// Asynchronized request
let request = iconService.sendTransaction(signedTransaction: signed)
request.async { (result) in
    switch result {
    case .success(let result): // result == String
        print(result)
    case .failure(let error):
        print(error)
    }
}

class Wallet

class Wallet
A class which provides EOA functions. It enables you to create, transform to Keystore or load wallet from Keystore.

### Initialize
init(privateKey: PrivateKey?)

Parameters

ParameterTypeDescription
privateKeyPrivateKeyIf privateKey is null, it generates new private key while initializing.

Returns

Wallet - Wallet instance.

Example

// Create new wallet
let wallet = Wallet(prviateKey: nil)    // will generate private key

// Imports from exist private key
let privateKey = PrivateKey(hexData: privateKeyData)
let wallet = Wallet(privateKey: privateKey)
// Loading wallets and storing the Keystore

// Save wallet keystore.
let wallet = Wallet(privateKey: nil)
do {
    try wallet.generateKeystore(password: "YOUR_WALLET_PASSWORD")
    try wallet.save(filepath: "YOUR_STORAGE_PATH")
} catch {
    // handle errors
}

// Load a wallet from the keystore.
do {
    let jsonData: Data = try Data(contentsOf: "YOUR_KEYSTORE_PATH")
    let decoder = JSONDecoder()
    let keystore = try decoder.decoder(Keystore.self, from: jsonData)
    let wallet = Wallet(keystore: keystore, password: "YOUR_WALLET_PASSWORD")
} catch {
    // handle errors
}

func getSignature

Generate signature string by signing transaction data.

func getSignature(data: Data) throws -> String

Parameter

ParameterTypeDescription
dataDatathe serialized transaction data.

Returns

String - A signature string.(Base64 encoded)

Example

let wallet = Wallet(privateKey: nil)
do {
    let signature = try wallet.getSignature(data: toBeSigned)
    print("signature - \(signature)")
} catch {
    // handle error
}

Properties

PropertyTypeDescription
addressStringReturn wallet's address (read-only)

class Transaction

class Transaction

Transaction is a class representing a transaction data used for sending ICX.

Initialize

// Create empty transaction object
init()
// Create transaction with data
convenience init(from: String, to: String, stepLimit: BigUInt, nid: String, value: BigUInt, nonce: String, dataType: String? = nil, data: Any? = nil)

Parameters

ParameterDescription
fromAn EOA address that creates the transaction.
toAn EOA address to receive coins or SCORE address to execute the transaction.
stepLimitAmounts of Step limit.
nidA network ID.
valueSending the amount of ICX in loop unit.
nonceAn arbitrary number used to prevent transaction hash collision.

func from

Setter for from property.

func from(_ from: String) -> Self

Parameters

ParameterTypeDescription
fromStringAn EOA address that creates the transaction.

Returns

Returns Transaction itself.

Example

// Set from property
let transaction = Transaction()
        .from("hx9043346dbaa72bca42ecec6b6e22845a4047426d")

func to

Setter for to property.

func to(_ to: String) -> Self

Paramters

ParamterTypeDescription
toStringAn EOA or SCORE address.

Returns

Returns Transaction itself.

Example

let transaction = Transaction()
        .to("hx2e26d96bd7f1f46aac030725d1e302cf91420458")

func stepLimit

Setter for setpLimit property.

func stepLimit(_ limit: BigUInt) -> Self

Parameters

ParameterTypeDescription
limitBigUIntAmounts of Step limit

Returns

Returns Transaction itself.

Example

let transaction = Transaction()
        .stepLimit(BigUInt(1000000))

func nid

Setter for nid property.

func nid(_ nid: String) -> Self

Parameters

ParameterTypeDescription
nidStringA network ID. (Mainnet = "0x1", Testnet = "0x2", etc)

Returns

Returns Transaction itself.

Example

let transaction = Transaction()
        .nid("0x1")

func value

Setter for value property.

func value(_ value: BigUInt) -> Self

Parameters

ParameterTypeDescription
valueBigUIntSending amount of ICX in loop unit. (1 ICX = 1018 loop)

Returns

Returns Transaction itself.

Example

let transaction = Transaction()
    .value(BigUInt(15000000))

func nonce

Setter for nonce property.

func nonce(_ nonce: String) -> Self

Parameters

ParameterTypeDescription
nonceStringA nonce value.

Returns

Returns Transaction itself.

Example

let transaction = Transaction()
    .nonce("0x1")
// Creating transaction instance for Sending ICX.
let transaction = Transaction()
    .from("hx9043346dbaa72bca42ecec6b6e22845a4047426d")
    .to("hx2e26d96bd7f1f46aac030725d1e302cf91420458")
    .value(BigUInt(15000000))
    .stepLimit(BigUInt(1000000))
    .nid("0x1")
    .nonce("0x1")

class CallTransaction

class CallTransaction: Transaction

CallTransaction class is used for invoking a state-transition function of SCORE. It extends Transaction class, so instance parameters and methods of the class are mostly identical to Transaction class, except for the following:

Parameters

ParametersDescription
methodThe method name of SCORE API.
paramsThe input params for method.

For details of extended parameters and methods, see Transaction section.

func method

Transaction for invoking a state-transition function of SCORE.

Transaction parameter dataType will be fixed with call

func method(_ method: String) -> Self

Parameters

ParameterTypeDescription
methodStringthe method name of SCORE API.

Returns

Returns CallTransaction itself.

params

The input parameters of the SCORE method that will be executed by call function.

func params(_ params: [String: Any]) -> Self

Parameter

ParameterTypeDescription
paramsDictionary<String: Any>Input parameters for call method.

Returns

Returns CallTransaction itself.

Example

// Creating transaction instance for SCORE function call
let call = CallTransaction()
    .from(wallet.address)
    .to("cx000...001")
    .stepLimit(BigUInt(1000000))
    .nid(self.iconService.nid)
    .nonce("0x1")
    .method("transfer")
    .params(["_to": to, "_value": "0x1234"])

class MessageTransaction

class MessageTransaction: Transaction

MessageTransaction class is used for sending message data. It extends Transaction class, so instance parameters and methods of the class are mostly identical to Transaction class, except for the following:

Parameters

ParametersDescription
messageA message to send.

For details of extended parameters and methods, see Transaction section.

func message

Send messages.

Transaction parameter dataType will be fixed with message.

func message(_ message: String) -> Self

Parameters

ParameterTypeDescription
messageStringA message String.

Returns

Returns MessageTransaction itself.

Example

// Creating transaction instance for transfering message.
let messageTransaction = MessageTransaction()
    .from("hx9043346dbaa72bca42ecec6b6e22845a4047426d")
    .to("hx2e26d96bd7f1f46aac030725d1e302cf91420458")
    .value(BigUInt(15000000))
    .stepLimit(BigUInt(1000000))
    .nonce("0x1")
    .nid("0x1")
    .message("Hello, ICON!")

class SignedTransaction

SignedTransaction is a class to make a signed transaction.

Initialize

init(transaction: Transaction, privateKey: PrivateKey)

Parameters

ParameterTypeDescription
transactionTransactionA transaction that will be signed.
privateKeyPrivateKeyA privateKey.

Example

let signed = try SignedTransaction(transaction: transaction, privateKey: yourPrivateKey)

ICError

There are 5 types of errors.

  • emptyKeystore - Keystore is empty.

  • invalid

    • missing(parameter: JSONParameterKey) - Missing JSON parameter.
    • malformedKeystore - Keystore data malformed.
    • wrongPassword - Wrong password.
  • fail

    • sign - Failed to sign.
    • parsing - Failed to parse.
    • decrypt - Failed to decrypt.
    • convert - Failed to convert to URL or data.
  • error(error: Error)

  • message(error: String) - JSON RPC Error Messages

Converter Functions

ICONKit supports converter functions.

convert()

Convert ICX or gLoop to loop.

1 ICX = 109 gLoop = 1018 loop

Paramters

ParametersTypeDescription
unitUnitThe unit of value( .icx, .gLoop, .loop ). Default value is .icx.

Returns

BigUInt - The value that converted to loop.

Example

let balance: BigUInt = 100

// Convert ICX to loop.
let ICXToLoop: BigUInt = balance.convert() // 100000000000000000000

// Convert gLoop to loop
let gLoopToLoop: BigUInt = balance.convert(unit: .gLoop) // 100000000000

toHexString()

Convert BigUInt value to hex String.

public func toHexString(unit: Unit = .loop) -> String

Parameters

ParametersTypeDescription
unitUnitThe unit of value( .icx, .gLoop, .loop ). Default value is .loop.

Returns

String - The value converted to a hex String.

Example

// Convert `BigUInt` value to hex `String`.
let ICXToLoop: BigUInt = 100000000000000000000
let hexString: String = ICXToLoop.toHexString() // 0x56bc75e2d63100000

hexToBigUInt()

Convert hex String to BigUInt.

public func hexToBigUInt(unit: Unit = .loop) -> BigUInt?

Parameters

ParametersTypeDescription
unitUnitThe unit of value( .icx, .gLoop, .loop ). Default value is .loop.

Returns

BigUInt - The value that converted to hex String.

If the conversion is failed, return nil.

Example

// Convert hex `String` to `BigUInt`.
let hexString: String = "0x56bc75e2d63100000"
let hexBigUInt: BigUInt = hexString.hexToBigUInt()! // 100000000000000000000

References

Updated about a year ago

Swift API Reference


The source code is found on GitHub at https://github.com/icon-project/ICONKit

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