w3
Package w3
implements a blazing fast and modular Ethereum JSON RPC client with
first-class ABI support.
- Batch request support significantly reduces the duration of requests to both remote and local endpoints.
- ABI bindings are specified for individual functions using Solidity syntax.
No need for
abigen
and ABI JSON files. - Modular API allows to create custom RPC method integrations that can be used alongside the methods implemented by the package.
w3
is closely linked to go-ethereum (opens in a new tab)
and uses a variety of its types, such as common.Address
(opens in a new tab)
or types.Transaction
(opens in a new tab).
Batch requests with w3
are up to 85x faster than sequential requests with
go-ethereum/ethclient
.
Benchmarks
name ethclient time/op w3 time/op delta Call_BalanceNonce 78.3ms ± 2% 39.0ms ± 1% -50.15% (p=0.000 n=23+22) Call_Balance100 3.90s ± 5% 0.05s ± 2% -98.84% (p=0.000 n=20+24) Call_BalanceOf100 3.99s ± 3% 0.05s ± 2% -98.73% (p=0.000 n=22+23) Call_Block100 6.89s ± 7% 1.94s ±11% -71.77% (p=0.000 n=24+23)
Install
go get github.com/lmittmann/w3
Getting Started
Note Check out the examples!
Connect to an RPC endpoint via HTTP, WebSocket, or IPC using Dial
(opens in a new tab)
or MustDial
(opens in a new tab).
// Connect (or panic on error)
client := w3.MustDial("https://rpc.ankr.com/eth")
defer client.Close()
Batch Requests
Batch request support in the Client
(opens in a new tab)
allows to send multiple RPC requests in a single HTTP request. The speed gains
to remote endpoints are huge. Fetching 100 blocks in a single batch request
with w3
is ~80x faster compared to sequential requests with ethclient
.
Example: Request the nonce and balance of an address in a single request
var (
addr = w3.A("0x000000000000000000000000000000000000c0Fe")
nonce uint64
balance big.Int
)
err := client.Call(
eth.Nonce(addr, nil).Returns(&nonce),
eth.Balance(addr, nil).Returns(&balance),
)
ABI Bindings
ABI bindings in w3
are specified for individual functions using Solidity
syntax and are usable for any contract that supports that function.
Example: ABI binding for the ERC20-function balanceOf
funcBalanceOf := w3.MustNewFunc("balanceOf(address)", "uint256")
A Func
(opens in a new tab) can be used to
- encode arguments to the contracts input data (
Func.EncodeArgs
(opens in a new tab)), - decode arguments from the contracts input data (
Func.DecodeArgs
(opens in a new tab)), and - decode returns form the contracts output data (
Func.DecodeReturns
(opens in a new tab)).
Reading Contracts
Func
(opens in a new tab)'s can be used with
eth.CallFunc
(opens in a new tab)
in the client to read contract data.
var (
weth9 = w3.A("0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2")
dai = w3.A("0x6B175474E89094C44Da98b954EedeAC495271d0F")
weth9Balance big.Int
daiBalance big.Int
)
err := client.Call(
eth.CallFunc(funcBalanceOf, weth9, addr).Returns(&weth9Balance),
eth.CallFunc(funcBalanceOf, dai, addr).Returns(&daiBalance),
)
Writing Contracts
Sending a transaction to a contract requires three steps.
- Encode the transaction input data using
Func.EncodeArgs
(opens in a new tab).
var funcTransfer = w3.MustNewFunc("transfer(address,uint256)", "bool")
input, err := funcTransfer.EncodeArgs(w3.A("0x…"), w3.I("1 ether"))
- Create a signed transaction to the contract using go-ethereum/core/types (opens in a new tab).
signer := types.LatestSigner(params.MainnetChainConfig)
tx := types.MustSignNewTx(privKey, signer, &types.DynamicFeeTx{
To: w3.A("0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2"),
Nonce: 0,
Data: input,
Gas: 75000,
GasFeeCap: w3.I("100 gwei"),
GasTipCap: w3.I("1 gwei"),
})
- Send the signed transaction.
var txHash common.Hash
err := client.Call(
eth.SendTx(tx).Returns(&txHash),
)
Custom RPC Methods
Custom RPC methods can be called with the w3
client by creating a
core.Caller
(opens in a new tab)
implementation.
The w3/module/eth
package can be used as implementation reference.
Utils
Static addresses, hashes, hex byte slices or big.Int
's can be parsed from
strings with the following utility functions.
var (
addr = w3.A("0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045")
hash = w3.H("0xd4e56740f876aef8c010b86a40d5f56745a118d0906a34e69aec8c0db1cb8fa3")
bytes = w3.B("0x27c5342c")
big = w3.I("12.34 ether")
)
Note that these functions panic if the string cannot be parsed. Use go-ethereum/common (opens in a new tab) to parse strings that may not be valid instead.
RPC Methods
List of supported RPC methods.
eth
(opens in a new tab)
Method | Go Code |
---|---|
eth_blockNumber | eth.BlockNumber().Returns(blockNumber *big.Int) |
eth_call | eth.Call(msg *w3types.Message, blockNumber *big.Int, overrides w3types.State).Returns(output *[]byte) eth.CallFunc(fn core.Func, contract common.Address, args ...any).Returns(returns ...any) |
eth_chainId | eth.ChainID().Returns(chainID *uint64) |
eth_createAccessList | eth.AccessList(msg *w3types.Message, blockNumber *big.Int).Returns(resp *eth.AccessListResponse) |
eth_estimateGas | eth.EstimateGas(msg *w3types.Message, blockNumber *big.Int).Returns(gas *uint64) |
eth_gasPrice | eth.GasPrice().Returns(gasPrice *big.Int) |
eth_getBalance | eth.Balance(addr common.Address, blockNumber *big.Int).Returns(balance *big.Int) |
eth_getBlockByHash | eth.BlockByHash(hash common.Hash).Returns(block *types.Block) eth.HeaderByHash(hash common.Hash).Returns(header *types.Header) |
eth_getBlockByNumber | eth.BlockByNumber(number *big.Int).Returns(block *types.Block) eth.HeaderByNumber(number *big.Int).Returns(header *types.Header) |
eth_getBlockTransactionCountByHash | eth.BlockTxCountByHash(hash common.Hash).Returns(count *uint) |
eth_getBlockTransactionCountByNumber | eth.BlockTxCountByNumber(number *big.Int).Returns(count *uint) |
eth_getCode | eth.Code(addr common.Address, blockNumber *big.Int).Returns(code *[]byte) |
eth_getLogs | eth.Logs(q ethereum.FilterQuery).Returns(logs *[]types.Log) |
eth_getStorageAt | eth.StorageAt(addr common.Address, slot common.Hash, blockNumber *big.Int).Returns(storage *common.Hash) |
eth_getTransactionByHash | eth.Tx(hash common.Hash).Returns(tx *types.Transaction) |
eth_getTransactionByBlockHashAndIndex | eth.TxByBlockHashAndIndex(blockHash common.Hash, index uint).Returns(tx *types.Transaction) |
eth_getTransactionByBlockNumberAndIndex | eth.TxByBlockNumberAndIndex(blockNumber *big.Int, index uint).Returns(tx *types.Transaction) |
eth_getTransactionCount | eth.Nonce(addr common.Address, blockNumber *big.Int).Returns(nonce *uint) |
eth_getTransactionReceipt | eth.TxReceipt(txHash common.Hash).Returns(receipt *types.Receipt) |
eth_sendRawTransaction | eth.SendRawTx(rawTx []byte).Returns(hash *common.Hash) eth.SendTx(tx *types.Transaction).Returns(hash *common.Hash) |
eth_getUncleByBlockHashAndIndex | eth.UncleByBlockHashAndIndex(hash common.Hash, index uint).Returns(uncle *types.Header) |
eth_getUncleByBlockNumberAndIndex | eth.UncleByBlockNumberAndIndex(number *big.Int, index uint).Returns(uncle *types.Header) |
eth_getUncleCountByBlockHash | eth.UncleCountByBlockHash(hash common.Hash).Returns(count *uint) |
eth_getUncleCountByBlockNumber | eth.UncleCountByBlockNumber(number *big.Int).Returns(count *uint) |
debug
(opens in a new tab)
Method | Go Code |
---|---|
debug_traceCall | debug.TraceCall(msg *w3types.Message, blockNumber *big.Int, config *debug.TraceConfig).Returns(trace *debug.Trace) debug.CallTraceCall(msg *w3types.Message, blockNumber *big.Int, overrides w3types.State).Returns(trace *debug.CallTrace) |
debug_traceTransaction | debug.TraceTx(txHash common.Hash, config *debug.TraceConfig).Returns(trace *debug.Trace) debug.CallTraceTx(txHash common.Hash, overrides w3types.State).Returns(trace *debug.CallTrace) |
txpool
(opens in a new tab)
Method | Go Code |
---|---|
txpool_content | txpool.Content().Returns(resp *txpool.ContentResponse) |
txpool_contentFrom | txpool.ContentFrom(addr common.Address).Returns(resp *txpool.ContentFromResponse) |
txpool_status | txpool.Status().Returns(resp *txpool.StatusResponse) |
web3
(opens in a new tab)
Method | Go Code |
---|---|
web3_clientVersion | web3.ClientVersion().Returns(clientVersion *string) |
Third Party RPC Method Packages
Package | Description |
---|---|
github.com/lmittmann/flashbots (opens in a new tab) | Package flashbots implements RPC API bindings for the Flashbots relay and mev-geth. |