node-ethereum-wallet

node-ethereum-wallet (ethereum-cli)

An Ethereum wallet for Node, browsers and command-line.

Powered by web3.js and eth-lightwallet.

This project is NOT affiliated with Ethereum.

Installing

Globally (for command line usage):

npm i node-ethereum-wallet -g

As a local module (for JS library usage):

npm i node-ethereum-wallet

Command-line Help

The ethereum-cli command will be available on your shell. The following arguments are available (the table below is available by running ethereum-cli with no arguments or ethereum-cli --help):

Command	Arguments	Description
--getaddress 🔑		Show your wallet's main address
--getnewaddress 🔑		Generates a new address and shows it
--listaddresses 🔑		Lists all your generated addresses
--privatekeytoaddress	privateKey	Converts a private key to address
--dumpprivkey 🔑	wallet	Shows the private key of one of your wallet addresses
--dumpwallet 🔑		Lists every private key of your wallet addresses
--dumpseed 🔑		Shows your seed (mnemonic phrase)
--getreceivedbyaddress	address [--minconf minimumConfirmations = 0]	Get an address' balance
--getbalance 🔑		Get your account's balance (all wallets summed up)
--getgasprice		Get current gas price
--getblockcount		Get current block's number
--getblock	blockNumberOrHash	Get a block's data
--gettransaction	txid	Get a transaction's data
--decoderawtransaction	hex	Decodes a raw transaction
--backupwallet 🔑	file	Backups your wallet onto file
--createrawtransaction 🔑	to --amount amount [--from from] [--gasprice gasprice] [--gaslimit gaslimit]	Returns an hex-encoded raw transaction
--signrawtransaction 🔑	hexRawTransaction --from from	Returns the hex-encoded raw transaction, signed by from
--sendrawtransaction	hexRawSignedTransaction	Pushes a raw transaction to the network
--sendtoaddress 🔑	to --amount amount [--from from] [--gasprice gasprice] [--gaslimit gaslimit]	Sends a transaction and returns its transaction ID. Amount will be interpreted as wei if no comma is found, or ether if comma is found (i.e. 1.0 = 1 ether; 1 = 1 wei)
--erc20	contractAddr [--abi abiOrFile]	Specify an ERC-20 contract to use (see below)

ERC-20 commands

Command	Arguments	Description
--erc20	contractAddr [--abi abiOrFile]	Specify an ERC-20 contract to use (see below)
--gettokendata	--erc20 contractAddr [--abi abiOrFile]	Get token data (name, symbol etc.) from contract, if available
--getbalance	address --erc20 contractAddr [--abi abiOrFile]	Get any wallet's balance. If address is not specified, it will return the sum of the balance of all your generated wallets
--sendtoaddress 🔑	address --erc20 contractAddr [--abi abiOrFile] --amount amount [--from _fromaddr]	Sends an amount of ERC-20 token to an address

Global options

• --password <password> Unlocks your wallet with your password. Required for every command marked with 🔑
• --provider <provider> (Optional) Use "ropsten" for MyEtherApi.com's Ropsten testnet, or a HTTP web3 provider URL. Default is MyEtherAPI.com mainnet provider.
• --testnet Alias for --provider testnet
• --datadir <folder> (Optional) Set folder used as wallet storage. Default is ~/.ethereum-cli.

First-run options

• --seed <seed> (Optional) Set a custom seed (useful for importing/restoring wallets). If not supplied, one will be generated.
• --password <password> (Optional) Pre-set a password. If not supplied, it will be requested.

Examples

Example 1: sending ether

$ ethereum-cli --getaddress
0xsample

$ ethereum-cli --getbalance
5000

$ ethereum-cli --sendtoaddress 0xtarget --from 0xsample --amount 3000
0xtransactionID

Example 2: sending ERC-20 tokens

$ ethereum-cli --erc20 0xcontract --abi ./contractabi.json --getbalance
5000

$ ethereum-cli --erc20 0xcontract --abi ./contractabi.json --sendtoaddress 0xtarget --amount 3000 
0xtransactionID

Library Help

This project also exposes a Javascript class, which you can use in your NodeJS or browser projects. It can be included on NodeJS using require:

const EthereumWallet = require('node-ethereum-wallet')

On browsers, you can include it using <script>, and the global class EthereumWallet will be available.

<script src="./node_modules/node-ethereum-wallet/lib/index.js"></script>

Initializing

You must instantiate the class and initialize it.

let myWallet = new EthereumWallet() // using MyEtherAPI.com web3 HTTP provider

The class constructor may receive an optional argument, setting a web3 server to connect to. By default, MyEtherAPI.com provider is used, however it has great limitations as it is intended for testing purposes only. It is highly recommended to set your own web3 provider. You may want to set up a web3 provider on AWS using Docker (note that it will cost you real money), or signup and use Infura services.

let myWallet = new EthereumWallet('https://mainnet.infura.io/<your infura key>') // using Infura provider

let myWallet = new EthereumWallet('https://localhost:8456') // using your local provider

You can modify the provider at any time using myWallet.setProvider(<provider>).

In order to initialize the wallet, call:

await myWallet.init()

It may receive an optional argument which is a folder where to keep the wallet data. By default, it is "~/.ethereum-cli". You can change it so:

await myWallet.init("/path/to/data/dir")

In order to check if your provider is still syncing, just check the boolean getter myWallet.isSyncing.

Creating wallet

If your wallet hasn't been created yet, it's needed to create it.

It's easy to check if your wallet has been created. Just check for the existence of a keystore.

if (await myWallet.hasKeystore) {
	// wallet exists
} else {
	// wallet does not exist
}

In order to create a wallet, you need a seed. Generate one so:

let seed = myWallet.generateSeed()

Save the seed safely, then create the keystore:

let password = 'your-wallet-password' // choose one
await myWallet.createKeystore(password, seed)

Unlocking your wallet

If you are going to perform any action that requires password (i.e. sending funds, signing transactions, generating wallets), unlock your wallet so:

await myWallet.unlock('your-wallet-password')

In order to check if your wallet is unlocked, just check if myWallet.isUnlocked is true.

Generating addresses

It is needed to generate an address. To do so, just call:

let address = await myWallet.getNewAddress()

It will return the new address as a string.

In order to generate multiple addresses, specify the amount of addresses to generate:

let addresses = await myWallet.getNewAddress(5)

It will return an array with the addresses.

If needed, you can get an address' private key with:

let privKey = myWallet.dumpPrivKey('address')

Or even convert a private key back to address:

let walletAddress = myWallet.privKeyToAddress(privKey)

An array of ever generated addresses is always available at:

let myAddresses = myWallet.addresses

Getting your balance

Your balance summed up (from all your wallets) can be obtained, in weis, through:

let balance = await myWallet.balance

Whereas the balance of an specified address is found with:

let balance = await myWallet.getBalance('address')

It can receive an optional argument, with the number of confirmations needed for a balance to be summed up (default is 1).

let balanceWith3Confs = await myWallet.getBalance('address', 3)

Blocks and Transactions

You can get the current block number with:

let blockCount = await myWallet.blockNumber

Information about a block is got with:

let blockInfo = await myWallet.getBlock(block_id_or_hash)

Information about a specified transaction is available by:

let txInfo = await myWallet.getTransaction('txid')

Gas

You can get the current gas price (median of the latest blocks).

let gasPrice = await myWallet.gasPrice

And estimate the gas needed for a transaction:

let gasLimit = await myWallet.estimateGas({
	value: 'tx amount',
	to: 'target wallet',
	gasPrice: await myWallet.gasPrice,
	nonce: myWallet.getNonce(fromWallet),
	data: 'optional'
})

Transaction

Sending Ether is as easy as:

let from_wallet = 'from_wallet' // your origin wallet or myWallet.addresses[0]
let to_wallet = 'destination'
let amount = 1*10e18 // in Wei (1*10^18 Wei = 1 Ether)

try {
	let txid = await myWallet.sendToAddress(from_wallet, to_wallet, amount)
} catch(e) {
	console.log("Could not send Ether. Reason: "+e.message)
}

The .sendToAddress method can also receive two additional arguments, gasPrice and gasLimit respectively, which, by default, are automaticaly calculated. If you want to skip gasPrice but set gasLimit, then set gasPrice as undefined.

Raw Transactions

You can create a hex-encoded raw transaction, instead of sending it directly. The usage of this method is the very same as .sendToAddress() and it returns your hex-encoded transaction as string.

let hexTx = await myWallet.createRawTx(from_wallet, to_wallet, amount)

Before sending your raw transaction, it is needed to sign it:

let signedHexTx = myWallet.signTx(hexTx, from)

Finally, push it:

try {
	let txid = await myWallet.sendRawTx(signedHexTx)
} catch(e) {
	console.log("Could not push tx. Reason: "+e.message)
}

Backup & Restore

You can get back your seed with:

let seed = myWallet.seed

It is not possible to recover your password (therefore, do not lose it). You can only get your seed after unlocking (myWallet.unlock(password)) your wallet with your password.

In order to restore your wallet, set the seed with createKeystore. You can specify a new password if you want.

let password = 'your-wallet-password' // choose one or use the previous one
await myWallet.createKeystore(password, 'your seed')

ERC-20 library

In order to use a ERC-20 library, it's needed to instance the main class (see above).

let myWallet = new EthereumWallet()
await myWallet.init()

Contract instance

You can have multiple contracts instance. Each contract interface is generated through a constructor.

let contract = myWallet.Erc20(contractAddress, contractAbi)

The contract address must be a string. The contract ABI can be either a string containing the location of a file containing the contract ABI or the ABI object itself. If not provided or null, a standard ABI will be used.

Getting token information

The lib also provides async getters that returns the token information.

Warning: storing token information on the contract is not covered by ERC-20 standards. Therefore, this feature may fail in several contracts. We recommend using try/catch or gathering these information from the ABI.

let contractName = await contract.name // "FakeCoin"
let contractSymbol = await contract.symbol // "FAKE"
let contractDecimals = await contract.decimals // 18
let contractTotalSupply = await contract.totalSupply // 2100000000000000000000000

Note: sequentially using await is bad practice ("async/await hell"). Read more.

Getting an address's balance

let balance = await contract.balanceOf(address, minconf) // 1000000000000000000

The first argument must be a string. The second argument is optional (if not provided, it will be zero).

Sending tokens

let txid = await contract.transfer(to, amount, {
	from: '0xfrom',
	gasPrice: 'optional',
	gasLimit: 'optional'
	})

Setting gasPrice and gasLimit are optional. If not provided, it will be estimated.

Amount is given on the lowest unit. For a token with 18 decimals, 1 token = 1e18 (1000000000000000000).

This function throws/rejects on error. Since it is async, you can either use try/catch or Promise.catch().

Todo

• [ ] ERC20 tokens support (60% done)
• [ ] Smart contracts support