NFT environment deployment - vnt.js

1. Operating environment

Installation required

node: v8.11.2

2. Initialize the deployment directory

mkdir deploy cd deploy npm init # This step will generate package.json

3. Installation dependency

Install vnt.js: 0.20.7 and vnt-kit.js 1.0.0

npm install --save https://github.com/vntchain/vnt.js.git npm install --save https://github.com/vntchain/vnt-kit.js.git

If the installation fails because the g + + package is missing, please install.

Centos: sudo Yum install gcc-c++

Please check other operating systems.

Install other dependencies

# These dependencies are that Ethereum has js tool libraries, and vntchain can be compatible with these tool libraries npm install --save [email protected] npm install --save ethereumjs-account

1. If you have a vntchain node

If you set up your own vntchain node by running go VNT, and your vntchain node joins the blockchain network. Then, you can use your node for account management, and use some relatively friendly vnt.js interfaces during development to reduce the amount of JS code development
But one thing to note: don't open your vntchain node to the public network, otherwise hackers may use your unlocked private key to steal

Step 1: import vnt.js Library

var Vnt = require("vnt")

Step 2: create vnt provider connection

var vnt = new Vnt(); vnt.setProvider(new vnt.providers.HttpProvider("http://192.168.0.110:8805"));

Step 3: prepare the account to be used and open the account

// Declare account address and password var from1 = "0x122369f04f32269598789998de33e3d56e2c507a" var pass1 = "" var from2 = "0x3dcf0b3787c31b2bdf62d5bc9128a79c2bb18829" var pass2 = "" var toAddr = "0x3ea7a559e44e8cabc362ca28b6211611467c76f3" // Open the account. After opening, the account key will be managed by the vntchain node and used as a transaction signature vnt.personal.unlockAccount(from1, pass1) vnt.personal.unlockAccount(from2, pass2)

Step 4: prepare contract code

Read code and abi from file system

var fs = require("fs") // This is the fs library used. Please introduce it at the beginning of the code //Define code path var codeFile = "/home/mycode/erc20/erc20.compress" //Define abi path var abiFile = "/home/mycode/erc20/abi.json" //Reading abi data var wasmabi = fs.readFileSync(abiFile) //Parsing abi data into json structure var abi = JSON.parse(wasmabi.toString("utf-8"))

Step 5: contract creation

//This is the contract creation main function function deployWasmContract() { // Initialize a contract object with abi and load the code file var contract = vnt.core.contract(abi).codeFile(codeFile) // Deployment contract // We don't need explicit signature here. The vntchain node will sign for us. We can deploy the contract by using an encapsulated friendly new interface var contractReturned = contract.new(1000000000, "bitcoin", "BTC", { from: from1, //The account corresponding to the from parameter will be used as the transaction signature data: contract.code, //Pass in the contract code as data gas: 4000000 }, function(err, myContract){ if(!err) { if(!myContract.address) { console.log("transactionHash: ", myContract.transactionHash) } else { console.log("contract address: ", myContract.address) } } }); }

Step 6: contract call

Give two examples

In this case, only some queries will be performed, and the status of the chain will not be changed. For example, query the token balance of an account

function GetAmount(address) { console.log("get ammount of address: ", address) // Generate contract instance var contract = vnt.core.contract(abi).at(contractAddr) // Call the GetAmount method of the contract. Note that call is used r = contract.GetAmount.call(address, ) console.log("result", r.toString()) }

function Transfer(from, to, amount) { // Generate contract instance var contract = vnt.core.contract(abi).at(contractAddr) // Call the transfer method of the contract to transfer. Note that sendTransaction is used contract.transfer.sendTransaction( to,amount,, function(err, txid) { if(err) { console.log("error happend: ", err) } else { getTransactionReceipt(txid, function(receipt) { console.log("status: ", receipt.status) GetAmount(to) }) } }) }

vnt.js sends transactions asynchronously. After sending transactions, it will directly return txid instead of waiting for the completion of transaction execution. Therefore, we need to write a method ourselves to wait for the completion of transactions:

// This method will query tx information every second until a result is returned, and will call the callback function function getTransactionReceipt(tx, cb) { var receipt = vnt.core.getTransactionReceipt(tx) if(!receipt) { setTimeout(function () { getTransactionReceipt(tx, cb) }, 1000); } else { cb(receipt) } }

2. If you do not have a vntchain node

If you do not have your own vntchain node, but develop by connecting to a node on the public network, you need to manage your own account, generate your own transaction body and sign it.

Step 1: import vnt.js library and ethereumjs TX library

var Vnt = require("vnt") var vntkit = require("vnt-kit") var Tx = require("ethereumjs-tx")

Step 2: create vnt provider connection

var vnt = new Vnt(); vnt.setProvider(new vnt.providers.HttpProvider("http://192.168.0.110:8805"));

Step 3: prepare the account to be used and open the account

Load the keystore and decrypt it to obtain the account private key

var ksDir = "/Users/yanfengxi/go/src/github.com/vntchain/vnt_test/ks/" var kFile1 = "UTC--2018-05-21T03-11-21.232362508Z--122369f04f32269598789998de33e3d56e2c507a" var pass1 = "" var kFile2 = "UTC--2018-05-21T03-11-29.472506793Z--3dcf0b3787c31b2bdf62d5bc9128a79c2bb18829" var pass2 = "" function openAccount(file, passwd) { var content = fs.readFileSync(file).toString("utf-8") return vntkit.account.decrypt(content, passwd, false) } var account1 = openAccount(ksDir + kFile1, pass1) var account2 = openAccount(ksDir + kFile2, pass2)

Step 4: prepare contract code

Read code and abi from file system

var fs = require("fs") // This is the fs library used. Please introduce it at the beginning of the code //Define code path var codeFile = "/home/mycode/erc20/erc20.compress" //Define abi path var abiFile = "/home/mycode/erc20/abi.json" //Reading abi data var wasmabi = fs.readFileSync(abiFile) //Parsing abi data into json structure var abi = JSON.parse(wasmabi.toString("utf-8"))

Step 5: contract creation

//This is the contract creation main function function deployWasmContract() { // Contract initialization through abi and code path var contract = vnt.core.contract(abi).codeFile(codeFile) // Generate contract creation data var data = contract.packContructorData(1000000000, "bitcoin", "BTC") // Estimate a gas value var gas = vnt.core.estimateGas(); // Get the next nonce value of account 1 var nonce = vnt.core.getTransactionCount(account1.address); // Generate the transaction structure, and specify fields such as nonce, gaspierce, gaslimit, value, data, etc var options = { nonce: vnt.toHex(nonce), gasPrice: vnt.toHex(30000000000000), gasLimit: vnt.toHex(gas), value: '0x00', data: data, chainId: 1 //chainId must be specified here, that is, the chainId of the node you are connected to, otherwise the transaction signature will make an error } // Generate transaction var tx = new Tx(options); // Use the prepared private key to sign the transaction tx.sign(new Buffer(account1.privateKey.substring(2,), "hex")); // Serialize transaction data var serializedTx = tx.serialize(); // Send transaction vnt.core.sendRawTransaction('0x' + serializedTx.toString('hex'), function(err, txHash) { if (err) { console.log("err happened: ", err) } else { // Print hash of transaction console.log("transaction hash: ", txHash); // Get list of transactions getTransactionReceipt(txHash, function(receipt) { console.log("tx receipt: ", receipt) console.log("tx status: ", receipt.status) console.log("contract address: ", receipt.contractAddress) }) } }); }

Step 6: contract call

Give two examples

In this case, only some queries will be performed, and the status of the chain will not be changed. For example, query the token balance of an account

function GetAmount(address) { console.log("get ammount of address: ", address) // Generate contract instance through abi var contract = vnt.core.contract(abi) var data = contract.packFunctionData("GetAmount", [address]); console.log("the data is: ", data) // Get the next nonce value of account 1 var nonce = vnt.core.getTransactionCount(account1.address); // Generate transaction structure, specify to, data and other fields var options = { to: contractAddr, // This field is the contract address data: data // This field is the data called by the contract } // Use the vnt.core.call method to query, and no transaction will be initiated var result = vnt.core.call(options) // Decode the result and get the result. console.log(contract.unPackOutput("GetAmount", result).toString()) }

function Transfer(from, to, amount) { // Using abi to generate contract instances var contract = vnt.core.contract(abi) // Generate the data used by the contract call. This data is to package the signature and parameters of the transfer method var data = contract.packFunctionData("transfer", [to, amount]); // Gets the next nonce value var nonce = vnt.core.getTransactionCount(from); // Generate transaction structure, specify to, nonce, gaspierce, gaslimit, value, data and other fields // Where the to field is the contract address and the data field is the data called by the contract var options = { to: contractAddr, nonce: vnt.toHex(nonce), gasPrice: vnt.toHex(30000000000000), gasLimit: vnt.toHex(4000000), value: '0x00', data: data } // Generate transaction var tx = new Tx(options); // Use the prepared private key to sign the transaction tx.sign(new Buffer(keyMap[from].privateKey.substring(2,), "hex")); // Serialize transaction data var serializedTx = tx.serialize(); // Send transaction vnt.core.sendRawTransaction('0x' + serializedTx.toString('hex'), function(err, txHash) { if (err) { console.log("err happened: ", err) } else { // Print hash of transaction console.log("transaction hash: ", txHash); // Get list of transactions getTransactionReceipt(txHash, function(receipt) { console.log("tx receipt: ", receipt) console.log("tx status: ", receipt.status) console.log("contract address: ", receipt.contractAddress) GetAmount(to) }) } }); }

VNT Javascript API

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