시작하기

이 문서는 caver-js 1.5.0 또는 상위 버전을 사용하는 개발자를 위해 작성되었습니다. If you are using an older version, see Getting Started (~v1.4.1).
준비 사항
의존성
caver-js 라이브러리를 사용하려면 다음 패키지가 필요합니다.
​Node.js​
​npm​
​gcc-c++​
​Solidity compiler​
참고 caver-js는 Node.js 버전 12와 14에서 실행 가능합니다. 권장되는 버전은 다음과 같습니다.
lts/erbium (12.21.0)
lts/fermium (14.16.0)
If you use a different version of the Node (for example, Node v15), utilize the Node Version Manager(nvm) to install and use the version supported by caver-js.
설치
다음 명령을 사용해 npm으로 caver-js를 설치하세요:
$ npm install caver-js
참고: package.json 파일이 설치 경로와 동일한 곳에 존재해야 합니다. 만일 존재하지 않으면, npm init을 통해 package.json가 생성될 수 있습니다.
caver-js의 특정 버전을 설치하려면 다음 명령을 이용하세요:
$ npm install [email protected]
caver-js 시작하기
Once you have finished installing caver-js, you can now connect to a Klaytn Node using caver-js.
To practice the examples below, first create a test file in the working directory.
$ touch test.js
작업 디렉토리에 생성된 test.js 파일을 확인할 수 있을 것입니다.
test.js에 다음 코드를 작성하세요.
// test.js
const Caver = require('caver-js')
const caver = new Caver('https://api.baobab.klaytn.net:8651/')
​
async function testFunction() {
    const version = await caver.rpc.klay.getClientVersion()
    console.log(version)
}
​
testFunction()
위 코드를 실행하면 아래 결과를 얻습니다.
$ node ./test.js
Klaytn/v1.4.0/linux-amd64/go1.14.1
If you see the output of console.log like above, proceed with the steps below. The version number can be different according to the version of the connected Klaytn node.
Klaytn 노드에 접속하기
아래 예시와 같이 caver-js 모듈을 가져와 Baobab 테스트넷의 Klaytn 노드에 연결할 수 있습니다:
const Caver = require('caver-js')
const caver = new Caver('https://api.baobab.klaytn.net:8651/')
EN을 실행 중인 경우, 아래와 같이 호스트와 포트를 변경하여 자신의 노드에 연결할 수 있습니다:
const Caver = require('caver-js')
const caver = new Caver('https://your.en.url:8651/')
Keyring 관리
​Keyring is a structure that contains the address of the Klaytn account and the private key(s).
​Keyring can be classified into three types depending on the type of key being stored: SingleKeyring to store one address and one private key, MultipleKeyring to store one address and multiple private keys, and RoleBasedKeyring to store one address and one or more private keys for each role.
​SingleKeyring defines key property inside, and this key store one private key.
​MultipleKeyring defines keys property inside, and this keys is implemented as an array to store multiple private keys.
The keys property defined in RoleBasedKeyring is implemented as a two-dimensional array (empty keys will look like [ [], [], [] ]) that can include multiple keys for each role. The first element of the array is filled with the private key(s) to be used for roleTransactionKey, the second element the private key(s) to be used for roleAccountUpdateKey, and the third element the private key(s) to be used for roleFeePayerKey.
Keyring 생성
SingleKeyring 생성
아래와 같이 임의의 값을 사용해 SingleKeyring을 생성할 수 있습니다.
// test.js
const Caver = require('caver-js')
const caver = new Caver('https://api.baobab.klaytn.net:8651/')
​
async function testFunction() {
    const keyring = caver.wallet.keyring.generate()
    console.log(keyring)
}
​
testFunction()
위 코드를 실행하면 아래 결과를 얻습니다.
$ node ./test.js
SingleKeyring {
    _address: '0x3d263c3c0df60c5516f932d244531742f45eed5c',
    _key: PrivateKey { _privateKey: '0x{private key}' }
}
The execution result is shown above. Member variables defined inside the instance can be accessed through keyring.address and keyring.key.
개인키로 SingleKeyring 생성하기
개인키가 있다면, 이 개인키를 사용해 Keyring을 만들 수 있습니다.
// test.js
const Caver = require('caver-js')
const caver = new Caver('https://api.baobab.klaytn.net:8651/')
​
async function testFunction() {
    // Create a keyring from a private key
    const keyringFromPrivateKey = caver.wallet.keyring.createFromPrivateKey('0x{private key}')
    console.log(keyringFromPrivateKey)
}
​
testFunction()
위 코드를 실행하면 아래 결과를 얻습니다.
$ node ./test.js
SingleKeyring {
    _address: '0xf5a9079f311f9ec55170af351627aff0c5d2e287',
    _key: PrivateKey { _privateKey: '0x{private key}' } 
}
The result of caver.wallet.keyring.createFromPrivateKey, like the result of caver.wallet.keyring.generate above, is a SingleKeyring instance with an address defined inside it and a [PrivateKey] instance in keyring.key.
개인키와 계정 주소로 SingleKeyring 생성하기
여러분의 Klaytn 계정 주소가 개인키로부터 생성된 것이 아니라 개인키와 별도로 분리된 것이라면, 주소와 개인키를 사용해 Keyring을 만들 수 있습니다.
// test.js
const Caver = require('caver-js')
const caver = new Caver('https://api.baobab.klaytn.net:8651/')
​
async function testFunction() {
    // Create a keyring with an address and a private key
    const keyring = caver.wallet.keyring.createWithSingleKey('0x{address in hex}', '0x{private key}')
    console.log(keyring)
​
    // Create a keyring from a KlaytnWalletKey
    const keyringFromKlaytnWalletKey = caver.wallet.keyring.createFromKlaytnWalletKey('0x{private key}0x{type}0x{address in hex}')
    console.log(keyringFromKlaytnWalletKey)
}
​
testFunction()
Run the code in your console like below.
$ node ./test.js
SingleKeyring {
    _address: '0x17e7531b40ad5d7b5fa7b4ec78df64ce1cb36d24',
    _key: PrivateKey { _privateKey: '0x{private key}' }
}
SingleKeyring {
    _address: '0x17e7531b40ad5d7b5fa7b4ec78df64ce1cb36d24',
    _key: PrivateKey { _privateKey: '0x{private key}' }
}
여러 개인키로 MultipleKeyring 생성하기
If you want to use multiple private keys, you can create a MultipleKeyring using an address and multiple private keys. The below examples show how to create a MultipleKeyring with multiple private keys.
// test.js
const Caver = require('caver-js')
const caver = new Caver('https://api.baobab.klaytn.net:8651/')
​
async function testFunction() {
    // Create a keyring with an address and private keys
    const keyring = caver.wallet.keyring.createWithMultipleKey('0x{address in hex}', [ '0x{private key1}', '0x{private key2}' ])
    console.log(keyring)
}
​
testFunction()
위 코드를 실행하면 아래 결과를 얻습니다.
$ node ./test.js
MultipleKeyring {
    _address: '0x17e7531b40ad5d7b5fa7b4ec78df64ce1cb36d24',
    _keys: [
        PrivateKey { _privateKey: '0x{private key1}' },
        PrivateKey { _privateKey: '0x{private key2}' } 
    ]
}
As you can see, _keys has multiple PrivateKey instances in the array. Member variables defined inside the instance can be accessed through keyring.address and keyring.keys.
개인키로 RoleBasedKeyring 생성하기
To use different private key(s) for each role, caver.wallet.keyring.createWithRoleBasedKey is used instead. Each array element represents a role described in RoleBasedKeyring. The example below shows how to create a RoleBasedKeyring instance from different keys for each role.
// test.js
const Caver = require('caver-js')
const caver = new Caver('https://api.baobab.klaytn.net:8651/')
​
async function testFunction() {
    // Create a keyring with an address and private keys defined by each roles
    const keyring = caver.wallet.keyring.createWithRoleBasedKey('0x{address in hex}', [
        [ '0x{private key1}', '0x{private key2}', '0x{private key3}' ],
        [ '0x{private key4}'],
        [ '0x{private key5}', '0x{private key6}' ],
    ])
    console.log(keyring)
}
​
testFunction()
위 코드를 실행하면 아래 결과를 얻습니다.
$ node ./test.js
RoleBasedKeyring {
    _address: '0x17e7531b40ad5d7b5fa7b4ec78df64ce1cb36d24',
    _keys: [ 
        [ 
            PrivateKey { _privateKey: '0x{private key1}' },
            PrivateKey { _privateKey: '0x{private key2}' },
            PrivateKey { _privateKey: '0x{private key3}' }
        ],
        [ PrivateKey { _privateKey: '0x{private key4}' } ],
        [ 
            PrivateKey { _privateKey: '0x{private key5}' },
            PrivateKey { _privateKey: '0x{private key6}' }
        ]
    ]
}
Looking at the output above, the first element of the keys array, roleTransactionKey, has three PrivateKey instances, and the second element, roleAccountUpdateKey, has one PrivateKey instance. And the last element of the array, roleFeePayerKey, has two PrivateKey instances.
Note: Calling functions related to keyring (caver.wallet.keyring) or wallet (caver.wallet) do not affect the actual Klaytn blockchain platform (Klaytn).
caver-js에 Keyring 추가하기
You can use a keyring easily by using the in-memory wallet provided by caver-js. The following examples illustrate how to add a keyring to a wallet using a keyring instance and a keystore file generated by Klaytn Wallet.
// test.js
const Caver = require('caver-js')
const caver = new Caver('https://api.baobab.klaytn.net:8651/')
​
async function testFunction() {
    // Using a keyring instance
    const keyring = caver.wallet.keyring.generate()
    caver.wallet.add(keyring)
    console.log(caver.wallet.getKeyring(keyring.address))
​
    // Using a keystore file
    const decrypted = caver.wallet.keyring.decrypt({ 
        version: 4,
        id: '9c12de05-0153-41c7-a8b7-849472eb5de7',
        address: '0xc02cec4d0346bf4124deeb55c5216a4138a40a8c',
        keyring: [
            { 
                ciphertext: 'eacf496cea5e80eca291251b3743bf93cdbcf7072efc3a74efeaf518e2796b15',
                cipherparams: { iv: 'd688a4319342e872cefcf51aef3ec2da' },
                cipher: 'aes-128-ctr',
                kdf: 'scrypt',
                kdfparams: {
                    dklen: 32,
                    salt: 'c3cee502c7157e0faa42386c6d666116ffcdf093c345166c502e23bc34e6ba40',
                    n: 4096,
                    r: 8,
                    p: 1
                },
                mac: '4b49574f3d3356fa0d04f73e07d5a2a6bbfdd185bedfa31f37f347bc98f2ef26'
            }
        ]
    }, 'password')
​
    caver.wallet.add(decrypted)
    console.log(caver.wallet.getKeyring(decrypted.address))
}
​
testFunction()
Run the in your console.
$ node ./test.js
SingleKeyring {
    _address: '0x66391720b488a3fb2c7c69d99cd4cd6e23ca18e3',
    _key: PrivateKey { _privateKey: '0x{private key}' }
}
SingleKeyring {
    _address: '0xc02cec4d0346bf4124deeb55c5216a4138a40a8c',
    _key: PrivateKey { _privateKey: '0x{private key}' }
}
위 결과를 살펴보면 caver.wallet에 Keyring을 추가하면 caver.wallet에서 여러분의 Keyring을 조회할 수 있습니다.
If you have an address and private key(s) to use, you can easily create a keyring and add it directly to caver.wallet via caver.wallet.newKeyring.
// test.js
const Caver = require('caver-js')
const caver = new Caver('https://api.baobab.klaytn.net:8651/')
​
async function testFunction() {
    // Add to wallet with an address and a private key
    const addedSingle = caver.wallet.newKeyring('0x{address in hex}', '0x{private key1}')
    console.log(caver.wallet.getKeyring(addedSingle.address))
​
    // Add to wallet with an address and private keys
    const addedMultiple = caver.wallet.newKeyring('0x{address in hex}', ['0x{private key2}', '0x{private key3}', '0x{private key4}'])
    console.log(caver.wallet.getKeyring(addedMultiple.address))
​
    // Add to wallet with an address and private keys defined by each roles
    const addedRoleBased = caver.wallet.newKeyring('0x{address in hex}', [
        ['0x{private key5}', '0x{private key6}', '0x{private key7}'],
        ['0x{private key8}', '0x{private key9}'],
        ['0x{private key10}', '0x{private key11}']
    ])
    console.log(caver.wallet.getKeyring(addedRoleBased.address))
}
​
testFunction()
위 코드를 실행하면 아래 결과를 얻습니다. The result of the above code execution is shown below. 개인키를 사용해 caver.wallet.newKeyring을 실행하면 개인키 1개를 가진 Keyring 인스턴스 1개가 생성되고 이 인스턴스는 caver.wallet에 추가됩니다. For multiple private keys, a Keyring instance with multiple private keys is created. When passing one or more private keys for each role as arguments, a Keyring instance with a different private key(s) for each role is created and also added to the caver.wallet.
$ node ./test.js
SingleKeyring {
    _address: '0x651f6ae6b45750082b22805583acc989399c6552',
    _key: PrivateKey { _privateKey: '0x{private key1}' }
}
MultipleKeyring {
    _address: '0xce3ee92aeb4d600a41c98bdf92e8b337e186bf58',
    _keys: [ 
        PrivateKey { _privateKey: '0x{private key2}' },
        PrivateKey { _privateKey: '0x{private key3}' },
        PrivateKey { _privateKey: '0x{private key4}' }
    ]
}
RoleBasedKeyring {
    _address: '0x626d5b94ec76a105c5afa370bb7e59050a22b8b5',
    _keys: [ 
        [ 
            PrivateKey { _privateKey: '0x{private key5}' },
            PrivateKey { _privateKey: '0x{private key6}' },
            PrivateKey { _privateKey: '0x{private key7}' }
        ],
        [ 
            PrivateKey { _privateKey: '0x{private key8}' },
            PrivateKey { _privateKey: '0x{private key9}' }
        ],
        [ 
            PrivateKey { _privateKey: '0x{private key10}' },
            PrivateKey { _privateKey: '0x{private key11}' }
        ]
    ]
}
caver.wallet에 Keyring 인스턴스를 추가하면 caver.wallet.add 또는 caver.wallet.newKeyring은 Keyring 인스턴스를 반환합니다.
트랜잭션 전송하기
This section will show you how to send KLAY using caver-js on the Baobab network.
Baobab Faucet을 통해 KLAY 받기
테스트를 위해 KLAY가 필요한 경우 Klaytn Wallet에서 Baobab testnet KLAY를 얻을 수 있습니다. 개인키 또는 키스토어 파일을 사용하여 Klaytn Wallet에 로그인하고 테스트를 위해 faucet을 통해 Baobab 테스트넷 KLAY를 받습니다.
송금 트랜잭션 전송
트랜잭션 서명은 caver-js 지갑을 통해 할 수 있습니다. 트랜잭션을 네트워크에 보내려면 아래와 같이 2단계를 거쳐야합니다.
1.트랜잭션 서명하기
If the keyring you want to use is added to caver.wallet, you can use caver.wallet.sign function to sign.
caver.wallet에 Keyring을 추가하지 않고 따로 관리한다면, transaction.sign 함수를 통해 트랜잭션에 서명할 수 있습니다.
2.RLP 인코딩된 서명된 트랜잭션을 caver.rpc.klay.sendRawTransaction을 통해 Klaytn에 전송합니다.
Note: The sender should have enough number of KLAY.
트랜잭션 서명하기
트랜잭션을 Klaytn에 보내기 전에 트랜잭션에 먼저 서명해야 합니다.
Below is an example of how to sign a transaction if a keyring is added to the caver.wallet.
// test.js
const Caver = require('caver-js')
const caver = new Caver('https://api.baobab.klaytn.net:8651/')
​
async function testFunction() {
    // Add a keyring to caver.wallet
    const keyring = caver.wallet.keyring.createFromPrivateKey('0x{private key}')
    caver.wallet.add(keyring)
​
    // Create a value transfer transaction
    const valueTransfer = caver.transaction.valueTransfer.create({
        from: keyring.address,
        to: '0x176ff0344de49c04be577a3512b6991507647f72',
        value: 1,
        gas: 30000,
    })
​
    // Sign the transaction via caver.wallet.sign
    await caver.wallet.sign(keyring.address, valueTransfer)
​
    const rlpEncoded = valueTransfer.getRLPEncoding()
    console.log(`RLP-encoded string: ${rlpEncoded}`)
}
​
testFunction()
위 코드는 Keyring을 caver.wallet에 추가하고, 트랜잭션을 생성하고, caver.wallet.sign를 통해 이 트랜잭션에 서명합니다.
위 코드를 실행하면 아래 결과를 얻습니다. 위 코드가 실행되었을 때, RLP 인코딩된 트랜잭션 문자열은 아래와 같이 나타납니다. (The RLP-encoded string output you got could be different from the string output shown below.)
RLP-encoded string: 0x08f87e808505d21dba0082753094176ff0344de49c04be577a3512b6991507647f720194ade4883d092e2a972d70637ca7de9ab5166894a2f847f845824e44a0e1ec99789157e5cb6bc691935c204a23aaa3dc049efafca106992a5d5db2d179a0511c421d5e508fdb335b6048ca7aa84560a53a5881d531644ff178b6aa4c0a41
RLP 인코딩된 서명된 트랜잭션을 Klaytn에 전송합니다.
이제, 아래와 같이 서명된 트랜잭션을 Klaytn에 전송할 수 있습니다. 아래 예시를 직접 실행하려면 0x{RLP-encoded string}를 위 rlpEncoded 값으로 대체하십시오 .
// test.js
const Caver = require('caver-js')
const caver = new Caver('https://api.baobab.klaytn.net:8651/')
​
async function testFunction() {
    const rlpEncoding = `0x{RLP-encoded string}`
​
    // Send the transaction using `caver.rpc.klay.sendRawTransaction`.
    const receipt = await caver.rpc.klay.sendRawTransaction(rlpEncoding)
    console.log(receipt)
}
​
testFunction()
위 코드를 실행하면 아래 결과를 얻습니다. When the above code is executed, the receipt of the transaction is shown below.
$ node ./test.js
{ 
    blockHash: '0xd20066b448da77a41a46fbf0856792b85b60c42213126f661f6434b5b1263072',
    blockNumber: '0x1efb',
    contractAddress: null,
    from: '0x09a08f2289d3eb3499868908f1c84fd9523fe11b',
    gas: '0x7530',
    ...
    signatures: [
        { 
            V: '0x4e43',
            R: '0x5737aa8c88f019a3ee184faed6d34d103f77773bd5434cb0328c11738c8d9755',
            S: '0x578b118f4400999e5232bd0860cfbdbf89622f6e11cc6bd9722a86767d2723b7'
        }
    ],
    status: '0x1',
    to: '0x176ff0344de49c04be577a3512b6991507647f72',
    transactionHash: '0x43e8ab1a2365ad598448b4402c1cfce6a71b3a103fce3a69905613e50b978113',
    transactionIndex: 0,
    type: 'TxTypeValueTransfer',
    typeInt: 8,
    value: '0x1'
}
caver.wallet 없이 트랜잭션에 서명하고 Klaytn에 서명된 트랜잭션을 보내려면 아래 예시를 확인하십시오.
// test.js
const Caver = require('caver-js')
const caver = new Caver('https://api.baobab.klaytn.net:8651/')
​
async function testFunction() {
    // Create a value transfer transaction
    const keyring = caver.wallet.keyring.createFromPrivateKey('0x{private key}')
    const valueTransfer = caver.transaction.valueTransfer.create({
        from: keyring.address,
        to: '0x176ff0344de49c04be577a3512b6991507647f72',
        value: 1,
        gas: 30000,
    })
​
    // Sign the transaction via transaction.sign
    await valueTransfer.sign(keyring)
​
    // Send the transaction to the Klaytn using `caver.rpc.klay.sendRawTransaction`.
    const receipt = await caver.rpc.klay.sendRawTransaction(valueTransfer)
    console.log(receipt)
}
​
testFunction()
When the above code is executed, the receipt of the transaction is printed like the previous example.
영수증 확인
You can use the promise or event emitter to get the receipt of the transaction when you transfer the transaction to the Klaytn by caver.rpc.klay.sendRawTransaction.
The following example shows how to get a receipt using promises and event emitters.
// Using a promise - async/await
const receipt = await caver.rpc.klay.sendRawTransaction(rawTransaction)
console.log(receipt)
​
// Using a promise
caver.rpc.klay.sendRawTransaction(rawTransaction).then(console.log)
​
// Using an event emitter
caver.rpc.klay.sendRawTransaction(rawTransaction).on('receipt', console.log)
위 예시와 같이 프로미스(promise)와 이벤트 이미터(event emitter)를 통해 트랜잭션을 전송한 결과를 가져올 수 있습니다. transactionHash 필드는 영수증 객체 내부에 정의됩니다. You can use caver.rpc.klay.getTransactionReceipt RPC call with receipt.transactionHash to query the receipt of a transaction at any time from the network after the transaction is included in a block. The example below shows how to get a receipt using the caver.rpc.klay.getTransactionReceipt RPC call.
// test.js
const Caver = require('caver-js')
const caver = new Caver('https://api.baobab.klaytn.net:8651/')
​
async function testFunction() {
    const receipt = await caver.rpc.klay.getTransactionReceipt('0x40552efbba23347d36f6f5aaba6b9aeb6602e004df62c1988d9b7b1f036e676a')
    console.log(receipt)
}
​
testFunction()
위 코드를 실행하면 아래 결과를 얻습니다. When the above code is executed, the receipt of the transaction is shown below.
$ node ./test.js
{ 
    blockHash: '0x65d041011440e04643c546eb8bbb1dcabb659c3b3216e01473cb0712e47b5f69',
    blockNumber: '0x20db',
    contractAddress: null,
    from: '0x09a08f2289d3eb3499868908f1c84fd9523fe11b',
    gas: '0x7530',
    ...
    signatures: [
        { 
            V: '0x4e43',
            R: '0xfabe48071a8b72f0c340b2ee9d948a496cce467aebe027159d66a175e6b4b5b4',
            S: '0x1d4e503f1b084cda15edeba6b7b8eba15057b9d2484f7f3d095c980c2d98f13'
        }
    ],
    status: '0x1',
    to: '0x176ff0344de49c04be577a3512b6991507647f72',
    transactionHash: '0x40552efbba23347d36f6f5aaba6b9aeb6602e004df62c1988d9b7b1f036e676a',
    transactionIndex: 0,
    type: 'TxTypeValueTransfer',
    typeInt: 8,
    value: '0x1'
}
트랜잭션의 실행 결과는 영수증의 status를 통하여 확인할 수 있습니다. For the details of the return values, see caver.rpc.klay.getTransactionReceipt. 만약 트랜잭션 실행이 실패한다면 에러에 대한 자세한 내용은 영수증의 txError에서 확인할 수 있습니다. txError에 대한 자세한 설명은 txError: Detailed Information of Transaction Failures를 참고하세요.
다른 트랜잭션 타입 실행하기
Klaytn은 확장성과 성능을 위한 다양한 트랜잭션 타입을 제공합니다. For more information, see Transactions. This section describes some examples that can be used with caver-js.
트랜잭션 수수료 위임
Klaytn provides Fee Delegation feature. 여기에서는, 여러분이 트랜잭션 전송자일 때 RLP 인코딩된 트랜잭션을 만드는 예시를 소개합니다.
// test.js
const Caver = require('caver-js')
const caver = new Caver('https://api.baobab.klaytn.net:8651/')
​
async function testFunction() {
    const sender = caver.wallet.keyring.createFromPrivateKey('0x{private key}')
    caver.wallet.add(sender)
​
    const feeDelegatedTx = caver.transaction.feeDelegatedValueTransfer.create({
        from: sender.address,
        to: '0x176ff0344de49c04be577a3512b6991507647f72',
        value: 5,
        gas: 50000,
    })
​
    await caver.wallet.sign(sender.address, feeDelegatedTx)
​
    const rlpEncoded = feeDelegatedTx.getRLPEncoding()
    console.log(rlpEncoded)
}
​
testFunction()
위 코드가 실행되었을 때, RLP 인코딩된 문자열이 출력됩니다. (The RLP-encoded string output you got could be different from the string output shown below.)
$ node ./test.js
0x09f884028505d21dba0082c35094176ff0344de49c04be577a3512b6991507647f720594f5a9079f311f9ec55170af351627aff0c5d2e287f847f845824e43a0f4b53dbd4c915cb73b9c7fa17e22106ee9640155a06ab4a7ed8661f846d2a5cca035b5bba6a26d4ccd20c65e8f31cce265c193f1c874806f9fae6b0ee9df0addf080c4c3018080
The fee payer can send the transaction to the Klaytn after attaching the feePayerSignatures to the RLP-encoded string (rawTransaction) signed by the transaction sender. If caver.wallet also has the fee payer's key, the fee payer's signature can be injected into feeDelegatedTx by calling caver.wallet.signAsFeePayer(feePayer.address, feeDelegatedTx). 그렇지 않다면, 수수료 납부자는 트랜잭션 발신자가 서명한 RLP 인코딩된 문자열에서 feeDelegatedTx를 새로 만들고, 자신의 서명을 여기에 추가해야합니다. 아래 예시를 참고하십시오. 아래 예시를 직접 실행하려면 0x{RLP-encoded string}를 위 rlpEncoded 값으로 대체하십시오 .
// test.js
const Caver = require('caver-js')
const caver = new Caver('https://api.baobab.klaytn.net:8651/')
​
async function testFunction() {
    const feePayer = caver.wallet.keyring.createFromPrivateKey('0x{private key}')
    caver.wallet.add(feePayer)
​
    const rlpEncoded = '0x{RLP-encoded string}'
​
    const feeDelegateTxFromRLPEncoding = caver.transaction.feeDelegatedValueTransfer.create(rlpEncoded)
​
    // Set the fee payer address.
    feeDelegateTxFromRLPEncoding.feePayer = feePayer.address
    await caver.wallet.signAsFeePayer(feePayer.address, feeDelegateTxFromRLPEncoding)
​
    console.log(feeDelegateTxFromRLPEncoding.getRLPEncoding())
}
​
testFunction()
위 코드가 실행되었을 때, 발신자 서명과 수수료 납부자 서명이 첨부된 RLP 인코딩된 문자열 아래와 같이 나타납니다. (The output you got could be different from the string output shown below.)
$ node ./test.js
0x09f8dc028505d21dba0082c35094176ff0344de49c04be577a3512b6991507647f720594f5a9079f311f9ec55170af351627aff0c5d2e287f847f845824e43a0f4b53dbd4c915cb73b9c7fa17e22106ee9640155a06ab4a7ed8661f846d2a5cca035b5bba6a26d4ccd20c65e8f31cce265c193f1c874806f9fae6b0ee9df0addf09417e7531b40ad5d7b5fa7b4ec78df64ce1cb36d24f847f845824e44a0921b7c3be69db96ce14134b306c2ada423613cb66ecc6697ee8067983c268b6ea07b86b255d1c781781315d85d7904226fb2101eb9498c4a03f3fbd30ba3ec5b79
이제 트랜잭션 발신자와 수수료 납부자 모두 트랜잭션에 서명했으니, 트랜잭션을 Klaytn에 전송할 수 있습니다. 0x{RLP-encoded string}을 위 예시 코드의 RLP 인코딩된 문자열 출력값으로 대체하십시오.
// test.js
const Caver = require('caver-js')
const caver = new Caver('https://api.baobab.klaytn.net:8651/')
​
async function testFunction() {
    const rlpEncoded = '0x{RLP-encoded string}'
    const receipt = await caver.rpc.klay.sendRawTransaction(rlpEncoded)
    console.log(receipt)
}
​
testFunction()
위 코드를 실행하면 아래 결과를 얻습니다. Through the execution result of the above code, you can check the FeeDelegatedValueTransfer transaction result.
$ node ./test.js
{ 
    blockHash: '0xb6a76163c4c558f50bdae77968a0f35dcfececf78b5cb780c3514a30a1c0a864',
    blockNumber: '0xede',
    contractAddress: null,
    feePayer: '0x17e7531b40ad5d7b5fa7b4ec78df64ce1cb36d24',
    feePayerSignatures: [
        {
            V: '0x4e44',
            R: '0x921b7c3be69db96ce14134b306c2ada423613cb66ecc6697ee8067983c268b6e',
            S: '0x7b86b255d1c781781315d85d7904226fb2101eb9498c4a03f3fbd30ba3ec5b79'
        }
    ],
    from: '0xf5a9079f311f9ec55170af351627aff0c5d2e287',
    gas: '0xc350',
    ...
    signatures: [
        {
            V: '0x4e43',
            R: '0xf4b53dbd4c915cb73b9c7fa17e22106ee9640155a06ab4a7ed8661f846d2a5cc',
            S: '0x35b5bba6a26d4ccd20c65e8f31cce265c193f1c874806f9fae6b0ee9df0addf0'
        }
    ],
    status: '0x1',
    to: '0x176ff0344de49c04be577a3512b6991507647f72',
    transactionHash: '0x1878cc27b7f259a98d3248b41bffb6158640b4a07c503095deac1913fb3856c2',
    transactionIndex: 0,
    type: 'TxTypeFeeDelegatedValueTransfer',
    typeInt: 9,
    value: '0x5'
}
계정 업데이트
If you want to change the private key(s) for your Klaytn account, there are 3 important things you need to remember:
1.Klaytn은 자신에게 전송되는 모든 트랜잭션을 검증합니다.
2.트랜잭션을 검증하려면 개인키와 짝을 이루는 공개키가 필요합니다.
3.따라서, 기존에 사용하던 개인키를 새로운 개인키로 바꾸기 전에, 먼저 기존 공개키를 새로운 공개키로 바꿔야 합니다. 새로운 공개키는 반드시 새로운 개인키로부터 만들어야 합니다.
Keeping the 3 things above in your mind, you can change your private key(s) by following the steps below:
1.새로운 Keyring을 만들기 위해 새 개인키(들)을 준비합니다.
2.필요한 Keyring 타입(SingleKeyring, MultipleKeyring, RoleBasedKeyring)을 골라 Keyring을 만듭니다.
3.새 Keyring에서 Account 인스턴스를 생성합니다. 이 Account 인스턴스는 여러분의 Klaytn 계정이 사용할 새로운 공개키를 가지고 있습니다.
4.Account 인스턴스를 입력 파라미터로 받는 AccountUpdate 트랜잭션을 Klaytn에 전송합니다.
5.마지막으로, 기존 Keyring을 2번째 단계에서 만들었던 새 Keyring으로 교체합니다.
Please check Account Update for the details.
To change your AccountKey, you must provide an Account instance for the account field in the input argument object of caver.transaction.accountUpdate. An Account instance contains the address of the Klaytn account and the AccountKey to be updated.
The code below is an example code that changes the private key(s) you use for your Klaytn account along with changing AccountKey of your Klaytn account to AccountKeyPublic. Don't forget to prepare your new private key(s).
// test.js
const Caver = require('caver-js')
const caver = new Caver('https://api.baobab.klaytn.net:8651/')
​
async function testFunction() {
    let sender = caver.wallet.keyring.createFromPrivateKey('0x{private key}')
    caver.wallet.add(sender)
​
    const newPrivateKey = caver.wallet.keyring.generateSingleKey()
    console.log(`new private key string: ${newPrivateKey}`)
    const newKeyring = caver.wallet.keyring.createWithSingleKey(sender.address, newPrivateKey)
​
    // create an Account instance
    const account = newKeyring.toAccount()
​
    const updateTx = caver.transaction.accountUpdate.create({
        from: sender.address,
        account: account,
        gas: 50000,
    })
    await caver.wallet.sign(sender.address, updateTx)
    const receipt = await caver.rpc.klay.sendRawTransaction(updateTx)
    console.log(receipt)
​
    // Update the keyring in caver.wallet for signing afterward.
    sender = caver.wallet.updateKeyring(newKeyring)
}
​
testFunction()
If the above code is executed successfully, you no longer are able to use the old private key(s) to sign any transaction with the old keyring. 따라서 여러분은 caver.wallet.updateKeyring(newKeyring)을 사용해 기존 Keyring을 newKeyring으로 업데이트하셔야 합니다. Once it is updated, the signing will be done by the newly updated private key(s).
위 코드를 실행하면 아래 결과를 얻습니다. In the execution result of the above code, the result of the private key and the account update that you should newly use are printed like below.
$ node ./test.js
new private key string: 0x{private key}
{ 
    blockHash: '0x4c0221245e7c810cc19b05257e8d7cd34f24cc829f8787a832c08682640173f5',
    blockNumber: '0x26d6',
    contractAddress: null,
    from: '0xeec694a4143e05945823b216d0c62ab91c192a63',
    gas: '0xc350',
    gasPrice: '0x5d21dba00',
    gasUsed: 41000,
    key: '0x02a1024cc461670797071be16c34b22df1a3588653da5c1e9279b1d9e4b24fbcba07d8',
    ...
    signatures: [
        {
            V: '0x4e43',
            R: '0xd0fa2d25711de4bfc3a7a6a660d307264fa3b2cacbb7eb71ab68f47661ebcfaf',
            S: '0x4652102241e61968988a22f9fa2d5d38d4e654d1f4b193fba5627c0856c9da7b'
        } 
    ],
    status: '0x1',
    transactionHash: '0x4efdeeb1bb1e52ace11d64a19f564a973b36c29a0d85899a215621659b793665',
    transactionIndex: 0,
    type: 'TxTypeAccountUpdate',
    typeInt: 32
}
Here comes how to update AccountKey of your Klaytn account with multiple [AccountKeys]? The example below explains how to create an Account instance with multiple private keys that what you want to use (You can create an Account instance with multiple public keys via caver.account.create). 여기에서도, 트랜잭션 객체의 account 필드에 Account 인스턴스를 입력 파라미터로 넣으면, 나머지 업데이트 과정은 위에서 소개한 AccountKey 1개를 업데이트하는 과정과 동일합니다.
First, let's create an Account instance to update with AccountKeyWeightedMultiSig. For AccountKeyWeightedMultiSig, a threshold and a weight for each key must be defined. To do this, use caver.account.weightedMultiSigOptions. 1번째 파라미터는 임계값이고 2번째 파라미터는 Key별 가중치를 담고 있는 배열입니다.
// Create an account instance with three private keys using AccountKeyWeightedMultiSig
const newPrivateKeys = caver.wallet.keyring.generateMultipleKeys(3)
const newKeyring = caver.wallet.keyring.createWithMultipleKey(sender.address, newPrivateKeys)
​
// threshold = 3, the weights of the three keys = [1, 2, 1]
const options = new caver.account.weightedMultiSigOptions(3, [1, 2, 1])
​
const account = newKeyring.toAccount(options)
Now let's update AccountKey using AccountKeyRoleBased. AccountKeyRoleBased is an AccountKey type that defines the key to use for each role.
// Create an account instance with roles using AccountKeyRoleBased. In the account instance created, each role has a public key that corresponds to one private key.
const newPrivateKeys = caver.wallet.keyring.generateRoleBasedKeys([1, 1, 1])
const newKeyring = caver.wallet.keyring.createWithRoleBasedKey(sender.address, newPrivateKeys)
​
const account = newKeyring.toAccount()
위 AccountKeyRoleBased는 Role마다 공개키 1개를 사용하는 예시입니다. 위 코드에서 볼 수 있듯이, 이들 각각은 개인키 1개에 대응됩니다. If you want to use multiple private keys for each role, caver.account.weightedMultiSigOptions must be defined for each role as shown below.
// Create an account instance with [3, 2, 3] keys for each role using AccountKeyRoleBased
const newPrivateKeys = caver.wallet.keyring.generateRoleBasedKeys([3, 2, 3])
const newKeyring = caver.wallet.keyring.createWithRoleBasedKey(sender.address, newPrivateKeys)
​
const options = [
    // thresold = 4, weights of keys = [2, 2, 4] for roleTransactionKey
    new caver.account.weightedMultiSigOptions(4, [2, 2, 4]),
    // threshold = 2, weights of keys = [1, 1]
    new caver.account.weightedMultiSigOptions(2, [1, 1]),
    // threshold = 3, weights of keys = [1, 1, 1]
    new caver.account.weightedMultiSigOptions(3, [1, 1, 1]),
]
​
const account = newKeyring.toAccount(options)
If you want to update AccountKey to AccountKeyLegacy or accountKeyFail, create an Account instance as shown below and assign it to the account field of the transaction.
// Create an account with AccountKeyLegacy
const accountWithLegacyKey = caver.account.createWithAccountKeyLegacy(keyringToUpdate.address)
​
// Create an account with AccountKeyFail
const accountWithFailKey = caver.account.createWithAccountKeyFail(keyringToUpdate.address)
스마트 컨트랙트
The caver.contract package makes it easy to interact with smart contracts on Klaytn. It automatically converts all methods of a smart contract into javascript calls when its low-level ABI (Application Binary Interface) is given. 이를 통해 스마트 컨트랙트가 마치 자바스크립트 객체인 것처럼 스마트 컨트랙트와 상호작용할 수 있습니다.
First, we make a simple solidity example like the below. Create a 'test.sol' file and write down the below example.
pragma solidity ^0.5.6;
​
contract KVstore {
    mapping(string=>string) store;
    function get(string memory key) public view returns (string memory) {
        return store[key];
    }
    function set(string memory key, string memory value) public {
        store[key] = value;
    }
}
Now we can compile a smart contract to get its bytecode and ABI.
> solc --abi --bin ./test.sol
======= ./test.sol:KVstore =======
Binary: 
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
Contract JSON ABI 
[{"constant":true,"inputs":[{"name":"key","type":"string"}],"name":"get","outputs":[{"name":"","type":"string"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":false,"inputs":[{"name":"key","type":"string"},{"name":"value","type":"string"}],"name":"set","outputs":[],"payable":false,"stateMutability":"nonpayable","type":"function"}]
참고: 스마트 컨트랙트를 컴파일하려면 솔리디티 컴파일러 가 설치되어 있어야 합니다.