Web3 Ethereum

Purpose¶

A helper layer over the Ethereum blockchain API: web3j

Methods¶

Binding name: p6.web3ethereum

decodeEventData¶

Decode the data returned by a web3j event using the list of solidity types (expressed as strings).

Syntax

List<Tuple2> p6.webethereum.decodeEventData(String data, String... solidityParamTypes)

Example

def lstData = p6.web3ethereum.decodeEventData( pipeline.get("logData"), "uint256")
println "Decoded log event data: " + lstData

decodeLogTopics¶

Decode the topics returned by a web3j event using the list of solidity types (expressed as strings).

Syntax

List<Tuple2> p6.webethereum.decodeLogTopics(String topicsData, String... solidityParamTypes)

Info

Topic data contains a maximum of four comma separated values. The first value is ignored as it’s “the hash of the signature of the event”.

See: https://github.com/ethereum/wiki/wiki/JSON-RPC#eth_getfilterchanges

Example

def lstData = p6.web3ethereum.decodeLogTopics( pipeline.get("logTopics"), "uint256")
println 'Decoded log event topics: ' + lstData

generateNewCredential¶

Generate new credentials using the supplied password and returning the credential as a JSON formatted String.

Syntax

String p6.webethereum.generateNewCredential(String password, boolean useFullCrypt)

Tip

The generated credentials can be ‘lite’ or ‘full’ based on useFullCrypt.

Example

println p6.webethereum.generateNewCredential("mypassword", true)

Load a Credentials object using a JSON string attached as a User property and password. The given propertyName is used to select the User property value.

Syntax

Credentials p6.webethereum.getCredentials(String userEmail, String propertyName, String password)

Info

The JSON can be a simple text User property or attached file.

Example

def credentials = p6.web3ethereum.getCredentials("user@server.com", "eth_credentials.json", "mypassword")

getCredentials (json)¶

Load a Credentials object using the supplied JSON string and password.

Syntax

Credentials p6.webethereum.getCredentials(String jsonSource, String password)

Example

def credentials = p6.web3ethereum.getCredentials(json, "mypassword")

noOpTransactionManager¶

Creates a Web3j RawTransactionManager which submits transactions and returns immediately with an empty TransactionReceipt.

Syntax

TransactionManager p6.webethereum.noOpTransactionManager(Web3j web3j, Credentials credentials)

Example

def web3j = p6.web3ethereum.build("http://127.0.0.1:8545")
def credentials = p6.web3ethereum.getCredentials(json, "mypassword")
def manager = p6.webethereum.noOpTransactionManager(web3j, credentials)

pollingTransactionManager¶

Creates a Web3j RawTransactionManager which submits transactions and blocks the call until it gets the transaction confirmation.

Syntax

TransactionManager p6.webethereum.pollingTransactionManager(
    Web3j web3j,
    Credentials credentials,
    long periodInMillis
    [, int nbOfAttempts]
)

Info

It does so by polling the blockchain every periodInMillis for a maximum number of nbOfAttempts times.

Parameter: nbOfAttempts

The nbOfAttempts parameter is optional and its default value is equal to TransactionManager.DEFAULT_POLLING_ATTEMPTS_PER_TX_HASH (40 in the current implementation of Web3j).

Example

def web3j = p6.web3ethereum.build("http://127.0.0.1:8545")
def credentials = p6.web3ethereum.getCredentials(json, "mypassword")
def manager = p6.webethereum.pollingTransactionManager(web3j, credentials, 60000)

pollingTransactionManager (with callback)¶

Creates a Web3j RawTransactionManager which submits transactions and returns immediately with an empty TransactionReceipt.

Syntax

TransactionManager p6.webethereum.pollingTransactionManager(
    Web3j web3j,
    Credentials credentials,
    Callback callback,
    long periodInMillis
    [, int nbOfAttempts]
)

Info

However, unlike the NoOp TransactionManager, you can register a callback to be later notified when the transaction manager manages to fetch the transaction confirmation. It does so by polling the blockchain every periodInMillis for a maximum number of nbOfAttempts times.

Parameter: nbOfAttempts

The nbOfAttempts parameter is optional and its default value is equal to TransactionManager.DEFAULT_POLLING_ATTEMPTS_PER_TX_HASH (40 in the current implementation of Web3j).

Example

def web3j = p6.web3ethereum.build("http://127.0.0.1:8545")
def credentials = p6.web3ethereum.getCredentials(json, "mypassword")
def manager = p6.webethereum.pollingTransactionManager(web3j, credentials, callback, 60000)

queuingTransactionManager¶

Similar to pollingTransactionManager() except that querying for transaction receipts happens on a single thread, which explains why a Callback is the only way to be notified of a transaction’s execution.

Syntax

TransactionManager p6.webethereum.queuingTransactionManager(
    Web3j web3j,
    Credentials credentials,
    Callback callback,
    long periodInMillis,
    int nbOfAttempts
)

Example

def web3j = p6.web3ethereum.build("http://127.0.0.1:8545")
def credentials = p6.web3ethereum.getCredentials(json, "mypassword")
def manager = p6.webethereum.queuingTransactionManager(web3j, credentials, callback, 60000, 10)

build¶

Initialises a Web3j instance. Allows IPC or HTTP URLs and an optional indication of Infura usage.

Syntax

org.web3j.protocol.Web3j p6.webethereum.build(String url, boolean infura)

build (with login/password)¶

Initialises a Web3j instance when connection to an Ethereum client requires a username / password.

Syntax

org.web3j.protocol.Web3j p6.webethereum.build(String url, String username, String password)

Example

def web3j = p6.web3ethereum.build("http://172.13.0.10:8545", "username", "mypassword")

buildAdmin¶

Creates an admin client for Parity or Geth providing support for commands like personal_newAccount.

Syntax

org.web3j.protocol.admin.Admin p6.webethereum.buildAdmin(String clientAddress, boolean ... infura)

Example

def admin = p6.webethereum.buildAdmin("http://172.13.0.10:8545")

getNextNonce¶

The nonce is an increasing numeric value which is used to uniquely identify transactions. This method returns the next nonce value to use for the given address.

Syntax

BigInteger p6.webethereum.getNextNonce(Web3j web3j, String address)

Example

def nonce = p6.web3ethereum.getNextNonce(web3j, "0xeEf629969b8B48975658f6a328E950ae5Ab78b45")

waitForTransactionReceipt¶

Waits for a transaction receipt given a transaction hash and web3j instance. Forty attempts with fifteen seconds intervals will be made before failure.

Syntax

TransactionReceipt p6.webethereum.waitForTransactionReceipt(Web3j web3j, String transactionHash)

Example

def web3j = p6.web3ethereum.build("http://172.13.0.10:8545")
def ethSendTransaction = web3j.ethSendRawTransaction(Numeric.toHexString(signedMessage)).sendAsync().get()
def transactionHash = ethSendTransaction.getTransactionHash()
def transactionReceipt = p6.web3ethereum.waitForTransactionReceipt(web3j, transactionHash)

waitForTransactionReceipt (with sleep and attempts)¶

Waits for a transaction receipt given a transaction hash and web3j instance.

Syntax

TransactionReceipt p6.webethereum.waitForTransactionReceipt(
    Web3j web3j,
    String transactionHash,
    int sleepDurationMillis,
    int attempts
)

Parameter: attempts

The Number of attempts and interval to wait (in milliseconds) is supplied.

Example

def web3j = p6.web3ethereum.build("http://172.13.0.10:8545")
def ethSendTransaction = web3j.ethSendRawTransaction(Numeric.toHexString(signedMessage)).sendAsync().get()
def transactionHash = ethSendTransaction.getTransactionHash()
def transactionReceipt = p6.web3ethereum.waitForTransactionReceipt(web3j, transactionHash, 60000, 10)

Binding Smart Contracts¶

This section explains how to use a smart contract written in the Solidity Contract-Oriented Programming Language from within a script.

Step 1: Create a web3j java class representing each contract

Please refer to https://github.com/amalto/solidity-jar-builder

Step 2: Make the Web3j class available to platform6

Copy the JAR file created in step one to ${P6_DATA}/lib and restart platform6

Note

If you add the JAR file to the Bundle Resources Service it will be automatically added to the classpath when it is deployed. This means there is no need to restart p6core

Step 3: Import the Class into your Script

Simply adding the import statement to you script will make you ‘contract’ class available.

Code

import com.amalto.platform6.solidity.model.*

Step 4: Load the contract and use it’s methods

Code

def web3j = p6.web3ethereum.build("http://127.0.0.1:8545")
def credentials = p6.web3ethereum.getCredentials(json, "password")

def ondifloContract = Ondiflo.load("0x7959edd693B202C183eFFf4dDA6c7a9702a7a82D", web3j, p6.web3ethereum.defaultTransactionManager(web3j, credentials), p6.web3ethereum.DEFAULT_GAS_PRICE, p6.web3ethereum.DEFAULT_GAS_LIMIT)

Once you have a reference to a loaded contract you can call it’s methods:

Code

def msg = ondifloContract.getMessage("0102030405060708".getBytes()).send()

Info

For more details see: https://docs.web3j.io/smart_contracts.html#solidity-smart-contract-wrappers

Web3 Ethereum

Purpose¶

Methods¶

decodeEventData¶

decodeLogTopics¶

generateNewCredential¶

getCredentials (login / password)¶

getCredentials (json)¶

noOpTransactionManager¶

pollingTransactionManager¶

pollingTransactionManager (with callback)¶

queuingTransactionManager¶

build¶

build (with login/password)¶

buildAdmin¶

getNextNonce¶

waitForTransactionReceipt¶

waitForTransactionReceipt (with sleep and attempts)¶

Binding Smart Contracts¶