web3j-quorum: Java integration library for Quorum

web3j-quorum is an extension to web3j providing support for JP Morgan's Quorum API.

web3j is a lightweight, reactive, type safe Java library for integrating with clients (nodes) on distributed ledger or blockchain networks.

For further information on web3j, please refer to the main project page and the documentation at Read the Docs.

Features

Support for Quorum's private transactions through private transaction manager
Ability to send signed private transactions
Works out the box with web3j's smart contract wrappers

Getting started

Add the relevant dependency to your project:

Maven

Java 8:

<dependency>
  <groupId>org.web3j</groupId>
  <artifactId>quorum</artifactId>
  <version>4.8.4</version>
</dependency>

Gradle

Java 8:

compile ('org.web3j:quorum:4.8.4')

Run Quorum

See instructions as per the Quorum project page

Start sending requests

To send synchronous requests:

Quorum quorum = Quorum.build(new HttpService("http://localhost:22001"));
Web3ClientVersion web3ClientVersion = quorum.web3ClientVersion().send();
String clientVersion = web3ClientVersion.getWeb3ClientVersion();

To send asynchronous requests:

Quorum quorum = Quorum.build(new HttpService("http://localhost:22001"));
Web3ClientVersion web3ClientVersion = quorum.web3ClientVersion().sendAsync().get();
String clientVersion = web3ClientVersion.getWeb3ClientVersion();

To use an RxJava Observable:

Quorum quorum = Quorum.build(new HttpService("http://localhost:22001"));
quorum.web3ClientVersion().observable().subscribe(x -> {
    String clientVersion = x.getWeb3ClientVersion();
    ...
});

IPC

web3j also supports fast inter-process communication (IPC) via file sockets to clients running on the same host as web3j. To connect simply use UnixIpcService or WindowsIpcService instead of HttpService when you create your service:

// OS X/Linux/Unix:
Quorum quorum = Quorum.build(new UnixIpcService("/path/to/socketfile"));
...

// Windows
Quorum quorum = Quorum.build(new WindowsIpcService("/path/to/namedpipefile"));
...

Smart Contract Wrappers

Smart contract wrappers generated using web3j 2.0+ work out the box with with web3j-quorum.

The only difference is that you'll need to use the Quorum ClientTransactionManager:

QuorumTransactionManager transactionManager = new QuorumTransactionManager(
        web3j, "0x<from-address>", Arrays.asList("<privateFor-public-key>", ...);
YourSmartContract contract = YourSmartContract.deploy(
    <web3j>, <transactionManager>, GAS_PRICE, GAS_LIMIT,
    <param1>, ..., <paramN>).send();

These wrappers are similar to the web3j smart contract wrappers with the exception that the transactions are signed by the Quorum nodes rather then by web3j. They also support the privateFor field on transactions.

See the web3j documentation for a detailed overview of smart contracts and web3j.

Sending Raw Private Transactions

web3j supports sending raw private transactions through a connection to Quorum Transaction Managers. Code examples

Connection to Tessera via HTTP

Credentials credentials = ...
//connect to quorum node via http or ipc as described above
Quorum quorum = ... 

EnclaveService enclaveService = new EnclaveService("http://TESSERA_THIRD_PARTY_URL", TESSERA_THIRD_PARTY_PORT, httpClient);
Enclave enclave = new Tessera(enclaveService, quorum);

QuorumTransactionManager qrtxm = new QuorumTransactionManager(
    quorum, credentials, TM_FROM_KEY, Arrays.asList(TM_TO_KEY_ARRAY),
    enclave,
    30,     // Retry times
    2000);  // Sleep

Connection to Tessera via IPC

Credentials credentials = ...
//connect to quorum node via http or ipc as described above
Quorum quorum = ... 

//build http client that supports ipc connection
UnixDomainSocketFactory socketFactory = new UnixDomainSocketFactory(new File("TESSERA_IPC_PATH"));
     OkHttpClient client = new OkHttpClient.Builder()
             .socketFactory(socketFactory)
             .build();

EnclaveService enclaveService = new EnclaveService("http://localhost", TESSERA_THIRD_PARTY_PORT, client);
Enclave enclave = new Tessera(enclaveService, quorum);

QuorumTransactionManager qrtxm = new QuorumTransactionManager(
    quorum, credentials, TM_FROM_KEY, Arrays.asList(TM_TO_KEY_ARRAY),
    enclave,
    30,     // Retry times
    2000);  // Sleep

Connection to Constellation via IPC

Credentials credentials = ...
//connect to quorum node via http or ipc as described above
Quorum quorum = ... 

//build http client that supports ipc connection
UnixDomainSocketFactory socketFactory = new UnixDomainSocketFactory(new File("CONSTELLATION_IPC_PATH"));
     OkHttpClient client = new OkHttpClient.Builder()
             .socketFactory(socketFactory)
             .build();

EnclaveService enclaveService = new EnclaveService("http://localhost", CONSTELLATION_THIRD_PARTY_PORT, client);
Enclave enclave = new Constellation(enclaveService, quorum);

QuorumTransactionManager qrtxm = new QuorumTransactionManager(
    quorum, credentials, TM_FROM_KEY, Arrays.asList(TM_TO_KEY_ARRAY),
    enclave,
    30,     // Retry times
    2000);  // Sleep

Using the QuorumTransactionManager with Smart Contract Wrappers

YourSmartContract.deploy(quorum,
    qrtxm,
    GAS_PRICE, GAS_LIMIT,
    <param1>, ..., <paramN>).send();

Using the QuorumTransactionManager alone

Using a single QuorumTransactionManager method signAndSend

RawTransaction rawTransaction = ...
EthSendTransaction ethSendTransaction = qrtxm.signAndSend(rawTransaction);

Using multiple exposed QuorumTransactionManager methods (storeRawRequest, sign, sendRaw)

//send raw bytecode to QuorumTranasctionManager
SendResponse storeRawResponse = qrtxm.storeRawRequest(HEX_ENCODED_SMARTCONTRACT_BYTECODE, TM_FROM_KEY, Arrays.asList(TM_TO_KEY_ARRAY));
String tesseraTxHash = Numeric.toHexString(Base64.getDecoder().decode(storeRawResponse.getKey()));

//create raw transaction with hash returned from QuorumTransactionManager
RawTransaction rawTransaction = ...

//sign raw transaction
String signedTx = qrtxm.sign(rawTransaction);

//send signed raw transaction to quorum node
EthSendTransaction ethSendTransaction = qrtxm.sendRaw(signedTx, Arrays.asList(TM_TO_KEY_ARRAY));

Retrieving a private transaction payload with Enclave receive method

String payload = enclave.receiveRequest(tesseraTxHash, TM_TO_KEY);

Full sample code

Sample code for sending raw private transactions via smart contract, QuorumTransactionManager and Enclave

Using web3j RawTransactionManager

// Raw txn
RawTransactionManager qrtxm = new RawTransactionManager(
      quorum,
      credentials,
      30,     // Retry times
      2000);  // Sleep

YourSmartContract.deploy(quorum,
      qrtxm,
      GAS_PRICE, GAS_LIMIT,
      <param1>, ..., <paramN>).send();

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