ERC20 Transfers

The Ruby Ethereum gem allows to easily handle tokens that implement the ERC-20 interface.

name = "DAI"
# => "DAI"
abi = '[{"inputs":[{"internalType":"uint256","name":"chainId_","type":"uint256"}],"payable":false,"stateMutability":"nonpayable","type":"constructor"},{"anonymous":false,"inputs":[{"indexed":true,"internalType":"address","name":"src","type":"address"},{"indexed":true,"internalType":"address","name":"guy","type":"address"},{"indexed":false,"internalType":"uint256","name":"wad","type":"uint256"}],"name":"Approval","type":"event"},{"anonymous":true,"inputs":[{"indexed":true,"internalType":"bytes4","name":"sig","type":"bytes4"},{"indexed":true,"internalType":"address","name":"usr","type":"address"},{"indexed":true,"internalType":"bytes32","name":"arg1","type":"bytes32"},{"indexed":true,"internalType":"bytes32","name":"arg2","type":"bytes32"},{"indexed":false,"internalType":"bytes","name":"data","type":"bytes"}],"name":"LogNote","type":"event"},{"anonymous":false,"inputs":[{"indexed":true,"internalType":"address","name":"src","type":"address"},{"indexed":true,"internalType":"address","name":"dst","type":"address"},{"indexed":false,"internalType":"uint256","name":"wad","type":"uint256"}],"name":"Transfer","type":"event"},{"constant":true,"inputs":[],"name":"DOMAIN_SEPARATOR","outputs":[{"internalType":"bytes32","name":"","type":"bytes32"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":true,"inputs":[],"name":"PERMIT_TYPEHASH","outputs":[{"internalType":"bytes32","name":"","type":"bytes32"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":true,"inputs":[{"internalType":"address","name":"","type":"address"},{"internalType":"address","name":"","type":"address"}],"name":"allowance","outputs":[{"internalType":"uint256","name":"","type":"uint256"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":false,"inputs":[{"internalType":"address","name":"usr","type":"address"},{"internalType":"uint256","name":"wad","type":"uint256"}],"name":"approve","outputs":[{"internalType":"bool","name":"","type":"bool"}],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":true,"inputs":[{"internalType":"address","name":"","type":"address"}],"name":"balanceOf","outputs":[{"internalType":"uint256","name":"","type":"uint256"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":false,"inputs":[{"internalType":"address","name":"usr","type":"address"},{"internalType":"uint256","name":"wad","type":"uint256"}],"name":"burn","outputs":[],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":true,"inputs":[],"name":"decimals","outputs":[{"internalType":"uint8","name":"","type":"uint8"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":false,"inputs":[{"internalType":"address","name":"guy","type":"address"}],"name":"deny","outputs":[],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":false,"inputs":[{"internalType":"address","name":"usr","type":"address"},{"internalType":"uint256","name":"wad","type":"uint256"}],"name":"mint","outputs":[],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":false,"inputs":[{"internalType":"address","name":"src","type":"address"},{"internalType":"address","name":"dst","type":"address"},{"internalType":"uint256","name":"wad","type":"uint256"}],"name":"move","outputs":[],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":true,"inputs":[],"name":"name","outputs":[{"internalType":"string","name":"","type":"string"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":true,"inputs":[{"internalType":"address","name":"","type":"address"}],"name":"nonces","outputs":[{"internalType":"uint256","name":"","type":"uint256"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":false,"inputs":[{"internalType":"address","name":"holder","type":"address"},{"internalType":"address","name":"spender","type":"address"},{"internalType":"uint256","name":"nonce","type":"uint256"},{"internalType":"uint256","name":"expiry","type":"uint256"},{"internalType":"bool","name":"allowed","type":"bool"},{"internalType":"uint8","name":"v","type":"uint8"},{"internalType":"bytes32","name":"r","type":"bytes32"},{"internalType":"bytes32","name":"s","type":"bytes32"}],"name":"permit","outputs":[],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":false,"inputs":[{"internalType":"address","name":"usr","type":"address"},{"internalType":"uint256","name":"wad","type":"uint256"}],"name":"pull","outputs":[],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":false,"inputs":[{"internalType":"address","name":"usr","type":"address"},{"internalType":"uint256","name":"wad","type":"uint256"}],"name":"push","outputs":[],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":false,"inputs":[{"internalType":"address","name":"guy","type":"address"}],"name":"rely","outputs":[],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":true,"inputs":[],"name":"symbol","outputs":[{"internalType":"string","name":"","type":"string"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":true,"inputs":[],"name":"totalSupply","outputs":[{"internalType":"uint256","name":"","type":"uint256"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":false,"inputs":[{"internalType":"address","name":"dst","type":"address"},{"internalType":"uint256","name":"wad","type":"uint256"}],"name":"transfer","outputs":[{"internalType":"bool","name":"","type":"bool"}],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":false,"inputs":[{"internalType":"address","name":"src","type":"address"},{"internalType":"address","name":"dst","type":"address"},{"internalType":"uint256","name":"wad","type":"uint256"}],"name":"transferFrom","outputs":[{"internalType":"bool","name":"","type":"bool"}],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":true,"inputs":[],"name":"version","outputs":[{"internalType":"string","name":"","type":"string"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":true,"inputs":[{"internalType":"address","name":"","type":"address"}],"name":"wards","outputs":[{"internalType":"uint256","name":"","type":"uint256"}],"payable":false,"stateMutability":"view","type":"function"}]'
# => "[{\"inputs\":[{\"internalType\":\"uint256\",\"name\":\"chainId_\",\"type\":\"uint256\"}],\"payable\":false,\"stateMutability\":\"nonpayable\",\"type\":\"constructor\"},{\"anonymous\":false,\"inputs\":[{\"indexed\":true,\"internalType\":\"address\",\"name\":\"src\",\"type\":\"address\"},{\"indexed\":true,\"internalType\":\"address\",\"name\":\"guy\",\"type\":\"address\"},{\"indexed\":false,\"internalType\":\"uint256\",\"name\":\"wad\",\"type\":\"uint256\"}],\"name\":\"Approval\",\"type\":\"event\"},{\"anonymous\":true,\"inputs\":[{\"indexed\":true,\"internalType\":\"bytes4\",\"name\":\"sig\",\"type\":\"bytes4\"},{\"indexed\":true,\"internalType\":\"address\",\"name\":\"usr\",\"type\":\"address\"},{\"indexed\":true,\"internalType\":\"bytes32\",\"name\":\"arg1\",\"type\":\"bytes32\"},{\"indexed\":true,\"internalType\":\"bytes32\",\"name\":\"arg2\",\"type\":\"bytes32\"},{\"indexed\":false,\"internalType\":\"bytes\",\"name\":\"data\",\"type\":\"bytes\"}],\"name\":\"LogNote\",\"type\":\"event\"},{\"anonymous\":false,\"inputs\":[{\"indexed\":true,\"internalType\":\"address\",\"name\":\"src\",\"type\":\"address\"},{\"indexed\":true,\"internalType\":\"address\",\"name\":\"dst\",\"type\":\"address\"},{\"indexed\":false,\"internalType\":\"uint256\",\"name\":\"wad\",\"type\":\"uint256\"}],\"name\":\"Transfer\",\"type\":\"event\"},{\"constant\":true,\"inputs\":[],\"name\":\"DOMAIN_SEPARATOR\",\"outputs\":[{\"internalType\":\"bytes32\",\"name\":\"\",\"type\":\"bytes32\"}],\"payable\":false,\"stateMutability\":\"view\",\"type\":\"function\"},{\"constant\":true,\"inputs\":[],\"name\":\"PERMIT_TYPEHASH\",\"outputs\":[{\"internalType\":\"bytes32\",\"name\":\"\",\"type\":\"bytes32\"}],\"payable\":false,\"stateMutability\":\"view\",\"type\":\"function\"},{\"constant\":true,\"inputs\":[{\"internalType\":\"address\",\"name\":\"\",\"type\":\"address\"},{\"internalType\":\"address\",\"name\":\"\",\"type\":\"address\"}],\"name\":\"allowance\",\"outputs\":[{\"internalType\":\"uint256\",\"name\":\"\",\"type\":\"uint256\"}],\"payable\":false,\"stateMutability\":\"view\",\"type\":\"function\"},{\"constant\":false,\"inputs\":[{\"internalType\":\"address\",\"name\":\"usr\",\"type\":\"address\"},{\"internalType\":\"uint256\",\"name\":\"wad\",\"type\":\"uint256\"}],\"name\":\"approve\",\"outputs\":[{\"internalType\":\"bool\",\"name\":\"\",\"type\":\"bool\"}],\"payable\":false,\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"constant\":true,\"inputs\":[{\"internalType\":\"address\",\"name\":\"\",\"type\":\"address\"}],\"name\":\"balanceOf\",\"outputs\":[{\"internalType\":\"uint256\",\"name\":\"\",\"type\":\"uint256\"}],\"payable\":false,\"stateMutability\":\"view\",\"type\":\"function\"},{\"constant\":false,\"inputs\":[{\"internalType\":\"address\",\"name\":\"usr\",\"type\":\"address\"},{\"internalType\":\"uint256\",\"name\":\"wad\",\"type\":\"uint256\"}],\"name\":\"burn\",\"outputs\":[],\"payable\":false,\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"constant\":true,\"inputs\":[],\"name\":\"decimals\",\"outputs\":[{\"internalType\":\"uint8\",\"name\":\"\",\"type\":\"uint8\"}],\"payable\":false,\"stateMutability\":\"view\",\"type\":\"function\"},{\"constant\":false,\"inputs\":[{\"internalType\":\"address\",\"name\":\"guy\",\"type\":\"address\"}],\"name\":\"deny\",\"outputs\":[],\"payable\":false,\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"constant\":false,\"inputs\":[{\"internalType\":\"address\",\"name\":\"usr\",\"type\":\"address\"},{\"internalType\":\"uint256\",\"name\":\"wad\",\"type\":\"uint256\"}],\"name\":\"mint\",\"outputs\":[],\"payable\":false,\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"constant\":false,\"inputs\":[{\"internalType\":\"address\",\"name\":\"src\",\"type\":\"address\"},{\"internalType\":\"address\",\"name\":\"dst\",\"type\":\"address\"},{\"internalType\":\"uint256\",\"name\":\"wad\",\"type\":\"uint256\"}],\"name\":\"move\",\"outputs\":[],\"payable\":false,\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"constant\":true,\"inputs\":[],\"name\":\"name\",\"outputs\":[{\"internalType\":\"string\",\"name\":\"\",\"type\":\"string\"}],\"payable\":false,\"stateMutability\":\"view\",\"type\":\"function\"},{\"constant\":true,\"inputs\":[{\"internalType\":\"address\",\"name\":\"\",\"type\":\"address\"}],\"name\":\"nonces\",\"outputs\":[{\"internalType\":\"uint256\",\"name\":\"\",\"type\":\"uint256\"}],\"payable\":false,\"stateMutability\":\"view\",\"type\":\"function\"},{\"constant\":false,\"inputs\":[{\"internalType\":\"address\",\"name\":\"holder\",\"type\":\"address\"},{\"internalType\":\"address\",\"name\":\"spender\",\"type\":\"address\"},{\"internalType\":\"uint256\",\"name\":\"nonce\",\"type\":\"uint256\"},{\"internalType\":\"uint256\",\"name\":\"expiry\",\"type\":\"uint256\"},{\"internalType\":\"bool\",\"name\":\"allowed\",\"type\":\"bool\"},{\"internalType\":\"uint8\",\"name\":\"v\",\"type\":\"uint8\"},{\"internalType\":\"bytes32\",\"name\":\"r\",\"type\":\"bytes32\"},{\"internalType\":\"bytes32\",\"name\":\"s\",\"type\":\"bytes32\"}],\"name\":\"permit\",\"outputs\":[],\"payable\":false,\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"constant\":false,\"inputs\":[{\"internalType\":\"address\",\"name\":\"usr\",\"type\":\"address\"},{\"internalType\":\"uint256\",\"name\":\"wad\",\"type\":\"uint256\"}],\"name\":\"pull\",\"outputs\":[],\"payable\":false,\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"constant\":false,\"inputs\":[{\"internalType\":\"address\",\"name\":\"usr\",\"type\":\"address\"},{\"internalType\":\"uint256\",\"name\":\"wad\",\"type\":\"uint256\"}],\"name\":\"push\",\"outputs\":[],\"payable\":false,\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"constant\":false,\"inputs\":[{\"internalType\":\"address\",\"name\":\"guy\",\"type\":\"address\"}],\"name\":\"rely\",\"outputs\":[],\"payable\":false,\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"constant\":true,\"inputs\":[],\"name\":\"symbol\",\"outputs\":[{\"internalType\":\"string\",\"name\":\"\",\"type\":\"string\"}],\"payable\":false,\"stateMutability\":\"view\",\"type\":\"function\"},{\"constant\":true,\"inputs\":[],\"name\":\"totalSupply\",\"outputs\":[{\"internalType\":\"uint256\",\"name\":\"\",\"type\":\"uint256\"}],\"payable\":false,\"stateMutability\":\"view\",\"type\":\"function\"},{\"constant\":false,\"inputs\":[{\"internalType\":\"address\",\"name\":\"dst\",\"type\":\"address\"},{\"internalType\":\"uint256\",\"name\":\"wad\",\"type\":\"uint256\"}],\"name\":\"transfer\",\"outputs\":[{\"internalType\":\"bool\",\"name\":\"\",\"type\":\"bool\"}],\"payable\":false,\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"constant\":false,\"inputs\":[{\"internalType\":\"address\",\"name\":\"src\",\"type\":\"address\"},{\"internalType\":\"address\",\"name\":\"dst\",\"type\":\"address\"},{\"internalType\":\"uint256\",\"name\":\"wad\",\"type\":\"uint256\"}],\"name\":\"transferFrom\",\"outputs\":[{\"internalType\":\"bool\",\"name\":\"\",\"type\":\"bool\"}],\"payable\":false,\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"constant\":true,\"inputs\":[],\"name\":\"version\",\"outputs\":[{\"internalType\":\"string\",\"name\":\"\",\"type\":\"string\"}],\"payable\":false,\"stateMutability\":\"view\",\"type\":\"function\"},{\"constant\":true,\"inputs\":[{\"internalType\":\"address\",\"name\":\"\",\"type\":\"address\"}],\"name\":\"wards\",\"outputs\":[{\"internalType\":\"uint256\",\"name\":\"\",\"type\":\"uint256\"}],\"payable\":false,\"stateMutability\":\"view\",\"type\":\"function\"}]"
address = "0x6B175474E89094C44Da98b954EedeAC495271d0F"
# => "0x6B175474E89094C44Da98b954EedeAC495271d0F"
dai = Eth::Contract.from_abi(name: name, address: address, abi: abi)
# => #<Eth::Contract::DAI:0x0000561abeb7f780>
client.call(dai, "name")
# => "Dai Stablecoin"
client.call(dai, "symbol")
# => "DAI"
client.call(dai, "decimals")
# => 18
client.call(dai, "totalSupply")
# => 5058734104652966852549722677
client.call(dai, "balanceOf", "0x9a315bdf513367c0377fb36545857d12e85813ef")
# => 86925992056395712941990039

To easily transfer a token, use .transfer_erc20 or .transfer_erc20_and_wait.

client.transfer_erc20_and_wait(dai, "0x49eB8f597De9B22D9141392d287BAfDc80994D51", 1, sender_key: my_key)
# => "0x5669979670d204bc1624ac9042c28fdef7c5e26d722872026cc7bb980482e280"
client.call(dai, "balanceOf", "0x49eB8f597De9B22D9141392d287BAfDc80994D51")
# => 1