lamden-js

This is the Lamden javascript implementation used in the Lamden Wallet Chrome Extention (Github).

This package should work in Node.js and Broswer implementations.

Install

npm install lamden-js

Test

npm run tests

Add to project

import Lamden from 'lamden-js'
or
const Lamden = require('lamden-js')

Wallet Functions

Create a Lamden Keypair

Creates a new wallet object.

• verifying key (vk): public key
• secret key (sk): private key

let lamdenWallet = Lamden.wallet.new_wallet()

console.log(lamdenWallet)
>> {
       vk: "ea2cee33f9478d767d67afe345592ef36446ee04f8d588fa76942e6569a53298",
       sk: "69a8db3fb7196debc2711fad1fa1935918d09f5d8900d84c3288ea5237611c03"
   }

Get a public key (vk) from a private key (sk)

Takes the sk as an argument and returns the vk

let sk = "69a8db3fb7196debc2711fad1fa1935918d09f5d8900d84c3288ea5237611c03"
let vk = wallet.get_vk(sk)

console.log(vk)
>> 'ea2cee33f9478d767d67afe345592ef36446ee04f8d588fa76942e6569a53298'

Sign a message

Signs a string payload

const stringBuffer = Buffer.from('message')
let messageBytes = new Uint8Array(stringBuffer);
let sk = "69a8db3fb7196debc2711fad1fa1935918d09f5d8900d84c3288ea5237611c03"

let signedMessage = wallet.sign(sk, messageBytes)

console.log(signedMessage)
>> '982c204fe88e620f3319558aa6b11f9d8be75b99b3199f434f5edf2834a9c52059ba4ea3d623ac1d550170e532e919c364aad1333f757f8f22e0355cb1dd8c09'

Verify signature

verify a payload

let validSignature = wallet.verify(vk, messageBytes, signedMessage)

console.log(validSignature)
>> true

Create a Lamden Transaction

Public Testnet masternode is http://167.172.126.5:18080

Create a Lamden Transaction

Use Lamden.TransactionBuilder(networkInfo, txInfo) to create a new Lamden transaction.

Create networkInfo object

create an object that describes the masternode/network that you are going to send the transcation to.

let networkInfo = {
    // Optional: Name of network
    name: 'Lamden Public Testnet',

    // Required: type of network 'mockchain', 'testnet', 'mainnet'
    type: 'testnet',

    // Required: must begin with http or https
    hosts: ['https://testnet-master-1.lamden.io:443']
}

Create txInfo object

create an object that describes the transaction you are going to send

//Sender and Receiver public keys
let senderVk = "ea2cee33f9478d767d67afe345592ef36446ee04f8d588fa76942e6569a53298"
let receiverVk = "bb0fab41b9118f0afdabf3721fa9a6caae3c93845ed409d3118841065ad1a197"

// Kwargs are the arugments you will send the contract method.  
// For example the "currency" contract's "transfer" method needs two arguments to create a transfter; the person reciving the TAU and the amount to transfer.  So we create a kwargs object like so.
let kwargs: {
        to: receiverVk,
        amount: 1000
}

let txInfo = {
    senderVk,
    contractName: "currency",
    methodName: "transfer",
    kwargs,
    stampLimit: 50000, //Max stamps to be used. Could use less, won't use more.
}

Create transaction

let tx = new Lamden.TransactionBuilder(networkInfo, txInfo)

Send transaction

let senderSk = "69a8db3fb7196debc2711fad1fa1935918d09f5d8900d84c3288ea5237611c03"

tx.send(senderSk, (res, err) => {
    if (err) throw new Error(err)
    console.log(res.hash)
    tx.checkForTransactionResult()
    .then(res => console.log(res))
})

//or

tx.events.on('response', (response) => {
    if (tx.resultInfo.type === 'error') return
    console.log(response)
})
tx.send(senderSk).then(() => tx.checkForTransactionResult())

Returns the NEW changed state in the currency contract for whatever variables the transfer method effected.
In this case, the new balances for both keys is returned

{
    state_changes: {
        "currency:balances:ea2cee33f9478d767d67afe345592ef36446ee04f8d588fa76942e6569a53298": "4895.0" // -1005 (amount + stamps)
        "currency:balances:bb0fab41b9118f0afdabf3721fa9a6caae3c93845ed409d3118841065ad1a197": "1000.0" // +1000
    }
    status_code: 0
    stamps_used: 13924
}

Getting a Nonce and Processor

Note: Nonce and processor will be retrieved from the masternode automatcially when send() is called.

getNonce() can be used to set the nonce and processor before hand.

let tx = new Lamden.TransactionBuilder(networkInfo, TxInfo)

tx.getNonce((res, err) => {
    if (err) {
        console.log("Nonce Not Set")
        return
    }
    console.log(res)
})

>> {
       "nonce": 37,
       "processor": "0000000000000000000000000000000000000000000000000000000000000000",
       "sender": "ea2cee33f9478d767d67afe345592ef36446ee04f8d588fa76942e6569a53298"
   }

Network and API

Create a network instance will allow you to call the masternode API. This class takes a "networkInfo" object as described above.

Create new Network instance

let testnet = new Network({
    name: 'Lamden Public Testnet',
    type: 'testnet',
    hosts: ['https://testnet-master-1.lamden.io:443']
})

testnet.events.on('online', (online) => {
    console.log(online)
    >> true or false
})
testnet.ping()

Netowrk API Endpoints

All API methods return a value, Promise or callback if provided

method	masternode endpoint	Description
getContractInfo(contractName)	/contracts/contractName	Returns the contract code of contractName example
getVariable(contractName, variableName, parms)	/contracts/contractName/variableName?key=parm	Retrieve the current state of a contract variable example
getContractMethods(contractName)	/contracts/contractName/methods	Returns all methods belonging to contractName example
pingServer()	/ping	Checks if network is online example
getCurrencyBalance(vk)	/contracts/currency/balances	A wrapper method for getVariable() which always returns the result of the currency contract's balances?key=vk example
contractExists(contractName)	/contracts/contractName	a wrapper method for getContractInfo() which returns if a contract exists on the blockchain
sendTransaction(txData, callback)	/	submits a contract to the network a txHash will be returned. Use checkTransaction() to get tx result
getNonce(senderVk, callback)	/nonce/senderVk	Get the current nonce and processor for a public key (vk)
checkTransaction(txHash, callback)	/tx?hash=txHash	Get the result of a transaction