web3-ebakus

Extend Web3 functionality for Ebakus blockchain.

Installation

Node.js

npm install --save web3-ebakus

In the Browser

Load it from CDN:

<script src="https://unpkg.com/web3-ebakus"></script>

You can find what is the latest version number of the library here. The script tag above to unpkg.com points to latest endpoint which does a redirect.

or build running the following from the root folder of the repository:

npm run-script build

Then include lib/web3-ebakus.browser.min.js in your html file. This will expose the Web3Ebakus object on the window object.

Requirements

• Web3 ^1.2.0

Usage

import Web3Ebakus from 'web3-ebakus'
import Web3 from 'web3'

const web3 = Web3Ebakus(new Web3())

You can also have a look at the example page.

Additionally you can use the library with web3-provider-engine. Check this section.

Methods

web3.eth.suggestDifficulty(accountAddress)

The suggestDifficulty queries the node for the suggested target difficulty needed for the PoW in order for a transaction to enter a block taking into account current congestion levels and address stake. The difficulty will be used in calculateWorkForTransaction.

web3.eth
  .suggestDifficulty(accountAddress)
  .then(difficulty => console.log(difficulty))

web3.eth.calculateWorkForTransaction(transaction, targetDifficulty, ctrlWorkForTransactionState, callback)

The calculateWorkForTransaction calculates the PoW needed for a transaction to enter a block by a block producer.

const tx = {
  /* transaction object */
}
web3.eth.calculateWorkForTransaction(tx, /* targetDifficulty */ 1).then(tx => {
  /* do something with tx */
})

is also available for Account objects, which is useful for chaining

The ctrlWorkForTransactionState and callback parameters are optional.

• ctrlWorkForTransactionState: this is an object that will be populated with some useful methods when passed.

  • isRunning(): state of worker
  • getCurrentWorkNonce(): returns the current workNonce while worker is running
  • kill(): kills the worker

  Example:

  let ctrl = {}
  
  // log worker state every 500ms
  const logger = setInterval(() => {
    console.log('isRunning', ctrl.isRunning())
    console.log('getCurrentWorkNonce', ctrl.getCurrentWorkNonce())
  
    // stop logging once worker finished
    if (!ctrl.isRunning()) {
      clearInterval(logger)
    }
  }, 500)
  
  // kill worker after 3seconds
  // setTimeout(() => {
  //   ctrl.kill();
  // }, 3000);
  
  web3.eth.calculateWorkForTransaction(transaction, 1, ctrl).then(tx => {
    /* do something with tx */
  })

• callback: you can read more here

web3.eth.estimatePoWTime(targetDifficulty, gas, callback)

The estimatePoWTime estimates how much time the current hardware will take for doing PoW based on target difficulty and transaction gas.

web3.eth.suggestDifficulty(accountAddress).then(difficulty => {
  web3.eth
    .estimatePoWTime(difficulty, /* gas */ 100000)
    .then(powTimeInSeconds => console.log(powTimeInSeconds))
})

• targetDifficulty: this is the target difficulty to achieve so as transaction gets produced. (default = 2)
• gas: this is the transaction gas. (default = 21000)
• callback: you can read more here

web3.eth.getAbiForAddress(contractAddress)

The getAbiForAddress returns the ABI for a contract, if this has been set by the developer.

web3.eth
  .getAbiForAddress(contractAddress)
  .then(abi => console.log(JSON.parse(abi)))

web3.eth.getStaked(accountAddress, blockNumber)

The getStaked returns the staked amount for an account.

• accountAddress: the account address.
• blockNumber: block number from which to read the staked amount. You can use latest string for fetching from latest block.

web3.eth
  .getStaked(accountAddress, 'latest')
  .then(staked => console.log('Staked amount is: ' + staked / 10000))

web3.db.select(contractAddress, tableName, whereCondition, orderByColumn, blockNumber)

The db.select allows performing selects with conditions ordered by column name.

• contractAddress: contract address that created the DB tables
• tableName: table name
• whereClause: where condition for finding an entry Supported conditions are "<", ">", "=", "==", "<=", ">=", "!=", "LIKE" Example use case: Phone = "555-1111" Id >= 3
• orderClause: order clause for sorting the results using "ASC" or "DESC" Example use case: Phone DESC
• blockNumber: block number to read from EbakusDB state. You can use latest string for fetching from latest block.

web3.db.select(contractAddress, tableName, whereCondition, orderByColumn, blockNumber)
  .then(iterator =>
    web3.db.next(iter).then(entry => console.log(entry)
  )

web3.db.next(iter)

The db.next returns the next result of the select performed through web3.db.select().

web3.db.releaseIterator(iter)

The db.releaseIterator should be called once, if not all iterator entries has been read using db.next, in order the iterator taken from db.select to be released.

web3.db.get(contractAddress, tableName, whereCondition, orderByColumn, blockNumber)

The db.get allows fetching a single item. Check for its params at web3.db.select().

web3.db
  .get(contractAddress, tableName, whereCondition, orderByColumn, blockNumber)
  .then(entry => console.log(entry))

Usage with web3-provider-engine

The web3-ebakus can be loaded as a subprovider of web3-provider-engine. For doing this you can load the subprovider from web3-ebakus/lib/web3-ebakus.web3-subprovider.node.js for targeting node.js or from web3-ebakus/lib/web3-ebakus.web3-subprovider.esm.js for targeting web. Check the following example code:

const Web3 = require('web3')
const ProviderEngine = require('web3-provider-engine')
const Web3EbakusSubprovider = require('web3-ebakus/lib/web3-ebakus.web3-subprovider.node.js')

const web3 = new Web3('https://rpc.ebakus-testnet.com')

const engine = new ProviderEngine()

const web3ebakus = new Web3EbakusSubprovider({ web3: web3 })
engine.addProvider(web3ebakus)

// ... add more providers as needed

engine.start()

web3.setProvider(engine)