VICTION Chain Integration

VICTION is an EVM-compatible public blockchain. So you can use TomoChain JSON-RPC APIs similar as in Ethereum.EVM compatible libraries such as Web3 library can be fully reused in integration to create a wallet, check wallet balances, or create/send transactions. All you need is to connect to TomoChain's RPC public endpoint. This tutorial will guide you the steps to connect to TomoChain Testnet/Mainnet.

Connect to TomoChain's public RPC endpoint

import Web3 from 'web3';​
const web3 = new Web3('https://rpc.tomochain.com');

Create a wallet

Generate an account object with private key and public key.

web3.eth.accounts.create([entropy]);

Example

web3.eth.accounts.create();
> {
    address: "0xb8CE9ab6943e0eCED004cDe8e3bBed6568B2Fa01",
    privateKey: "0x348ce564d427a3311b6536bbcff9390d69395b06ed6c486954e971d960fe8709",
    signTransaction: function(tx){...},
    sign: function(data){...},
    encrypt: function(password){...}
}

web3.eth.accounts.create('2435@#@#@±±±±!!!!678543213456764321§34567543213456785432134567');
> {
    address: "0xF2CD2AA0c7926743B1D4310b2BC984a0a453c3d4",
    privateKey: "0xd7325de5c2c1cf0009fac77d3d04a9c004b038883446b065871bc3e831dcd098",
    signTransaction: function(tx){...},
    sign: function(data){...},
    encrypt: function(password){...}
}

web3.eth.accounts.create(web3.utils.randomHex(32));
> {
    address: "0xe78150FaCD36E8EB00291e251424a0515AA1FF05",
    privateKey: "0xcc505ee6067fba3f6fc2050643379e190e087aeffe5d958ab9f2f3ed3800fa4e",
    signTransaction: function(tx){...},
    sign: function(data){...},
    encrypt: function(password){...}
}

Check wallet balances

Get account balance.

web3.eth.getBalance(address [, defaultBlock] [, callback])

Example

web3.eth.getBalance("0x407d73d8a49eeb85d32cf465507dd71d507100c1").then(console.log);> "1000000000000"

Create transaction

Send transaction to the network. You need to unlock wallet before using this function.

web3.eth.sendTransaction(transactionObject [, callback])

Parameters

1. Object - The transaction object to send:

   • from - String|Number: The address for the sending account. Uses the web3.eth.defaultAccount property, if not specified. Or an address or index of a local wallet in web3.eth.accounts.wallet.

   • to - String: (optional) The destination address of the message, left undefined for a contract-creation transaction.

   • value - Number|String|BN|BigNumber: (optional) The value transferred for the transaction in wei, also the endowment if it’s a contract-creation transaction.

   • gas - Number: (optional, default: To-Be-Determined) The amount of gas to use for the transaction (unused gas is refunded).

   • gasPrice - Number|String|BN|BigNumber: (optional) The price of gas for this transaction in wei, defaults to web3.eth.gasPrice.

   • data - String: (optional) Either a ABI byte string containing the data of the function call on a contract, or in the case of a contract-creation transaction the initialisation code.

   • nonce - Number: (optional) Integer of a nonce. This allows to overwrite your own pending transactions that use the same nonce.

2. callback - Function: (optional) Optional callback, returns an error object as first parameter and the result as second.

Example

const Web3 = require('web3')

// Connect to TomoChain nodes
const provider = new Web3.providers.HttpProvider('https://rpc.tomochain.com')
const web3 = new Web3(provider)

// Unlock wallet by private key
const account = web3.eth.accounts.privateKeyToAccount(pkey)
let coinbase = account.address
web3.eth.accounts.wallet.add(account)
web3.eth.defaultAccount = coinbase

// Make a transaction using the promise
web3.eth.sendTransaction({
    from: coinbase,
    to: '0x11f4d0A3c12e86B4b5F39B213F7E19D048276DAe',
    value: '1000000000000000'
})
.then(function(receipt){
    ...
});

Sign data

After unlock a wallet, you can sign some data

web3.eth.sign(dataToSign, address [, callback])

Parameters

1. 1.String - Data to sign. If String it will be converted using web3.utils.utf8ToHex.

2. 2.String|Number - Address to sign data with. Or an address or index of a local wallet in web3.eth.accounts.wallet.

3. 3.Function - (optional) Optional callback, returns an error object as first parameter and the result as second.

Example

const Web3 = require('web3')

// Connect to TomoChain nodes
const provider = new Web3.providers.HttpProvider('https://rpc.tomochain.com')
const web3 = new Web3(provider)

// Unlock wallet by private key
const account = web3.eth.accounts.privateKeyToAccount(pkey)
let coinbase = account.address
web3.eth.accounts.wallet.add(account)
web3.eth.defaultAccount = coinbase

// Make a transaction using the promise
web3.eth.sign('testdata').then(function(result){
    console.log(result)
});

Check transaction status

web3.eth.getTransactionReceipt(hash [, callback])

The receipt is not available for pending transactions and returns null.

Parameters

1. String - The transaction hash.

2. Function - (optional) Optional callback, returns an error object as first parameter and the result as second.

Returns

Promise returns Object - A transaction receipt object, or null when no receipt was found:

• status - Boolean: TRUE if the transaction was successful, FALSE, if the EVM reverted the transaction.

• blockHash 32 Bytes - String: Hash of the block where this transaction was in.

• blockNumber - Number: Block number where this transaction was in.

• transactionHash 32 Bytes - String: Hash of the transaction.

• transactionIndex - Number: Integer of the transactions index position in the block.

• from - String: Address of the sender.

• to - String: Address of the receiver. null when its a contract creation transaction.

• contractAddress - String: The contract address created, if the transaction was a contract creation, otherwise null.

• cumulativeGasUsed - Number: The total amount of gas used when this transaction was executed in the block.

• gasUsed - Number: The amount of gas used by this specific transaction alone.

• logs - Array: Array of log objects, which this transaction generated.

Irreversible blocks

In normal case, you can wait for 60 confirmations, then checking block finality via eth_getBlockFinalityByNumber or eth_getBlockFinalityByHash API:

• ​eth_getBlockFinalityByNumber​

• ​eth_getBlockFinalityByHash​

If result >= 75, it means the block with the input hash is finalized, thus irreversible.

How does TomoChain smart contract work?

TomoChain supports Solidity compiler version <= 0.5.0

Does TomoChain support multi-signature wallets?

Yes. Similar to Ethereum, you can use Gnosis MultiSigWallet.