// Copyright 2016 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
// Contains a wrapper for the Ethereum client.
package geth
import (
"math/big"
"github.com/ethereum/go-ethereum/core/types"
"github.com/ethereum/go-ethereum/core/vm"
"github.com/ethereum/go-ethereum/ethclient"
)
// EthereumClient provides access to the Ethereum APIs.
type EthereumClient struct {
client *ethclient.Client
}
// NewEthereumClient connects a client to the given URL.
func NewEthereumClient(rawurl string) (*EthereumClient, error) {
client, err := ethclient.Dial(rawurl)
return &EthereumClient{client}, err
}
// GetBlockByHash returns the given full block.
func (ec *EthereumClient) GetBlockByHash(ctx *Context, hash *Hash) (*Block, error) {
block, err := ec.client.BlockByHash(ctx.context, hash.hash)
return &Block{block}, err
}
// GetBlockByNumber returns a block from the current canonical chain. If number is <0, the
// latest known block is returned.
func (ec *EthereumClient) GetBlockByNumber(ctx *Context, number int64) (*Block, error) {
if number < 0 {
block, err := ec.client.BlockByNumber(ctx.context, nil)
return &Block{block}, err
}
block, err := ec.client.BlockByNumber(ctx.context, big.NewInt(number))
return &Block{block}, err
}
// GetHeaderByHash returns the block header with the given hash.
func (ec *EthereumClient) GetHeaderByHash(ctx *Context, hash *Hash) (*Header, error) {
header, err := ec.client.HeaderByHash(ctx.context, hash.hash)
return &Header{header}, err
}
// GetHeaderByNumber returns a block header from the current canonical chain. If number is <0,
// the latest known header is returned.
func (ec *EthereumClient) GetHeaderByNumber(ctx *Context, number int64) (*Header, error) {
if number < 0 {
header, err := ec.client.HeaderByNumber(ctx.context, nil)
return &Header{header}, err
}
header, err := ec.client.HeaderByNumber(ctx.context, big.NewInt(number))
return &Header{header}, err
}
// GetTransactionByHash returns the transaction with the given hash.
func (ec *EthereumClient) GetTransactionByHash(ctx *Context, hash *Hash) (*Transaction, error) {
tx, err := ec.client.TransactionByHash(ctx.context, hash.hash)
return &Transaction{tx}, err
}
// GetTransactionCount returns the total number of transactions in the given block.
func (ec *EthereumClient) GetTransactionCount(ctx *Context, hash *Hash) (int, error) {
count, err := ec.client.TransactionCount(ctx.context, hash.hash)
return int(count), err
}
// GetTransactionInBlock returns a single transaction at index in the given block.
func (ec *EthereumClient) GetTransactionInBlock(ctx *Context, hash *Hash, index int) (*Transaction, error) {
tx, err := ec.client.TransactionInBlock(ctx.context, hash.hash, uint(index))
return &Transaction{tx}, err
}
// GetTransactionReceipt returns the receipt of a transaction by transaction hash.
// Note that the receipt is not available for pending transactions.
func (ec *EthereumClient) GetTransactionReceipt(ctx *Context, hash *Hash) (*Receipt, error) {
receipt, err := ec.client.TransactionReceipt(ctx.context, hash.hash)
return &Receipt{receipt}, err
}
// SyncProgress retrieves the current progress of the sync algorithm. If there's
// no sync currently running, it returns nil.
func (ec *EthereumClient) SyncProgress(ctx *Context) (*SyncProgress, error) {
progress, err := ec.client.SyncProgress(ctx.context)
if progress == nil {
return nil, err
}
return &SyncProgress{*progress}, err
}
// NewHeadHandler is a client-side subscription callback to invoke on events and
// subscription failure.
type NewHeadHandler interface {
OnNewHead(header *Header)
OnError(failure string)
}
// SubscribeNewHead subscribes to notifications about the current blockchain head
// on the given channel.
func (ec *EthereumClient) SubscribeNewHead(ctx *Context, handler NewHeadHandler, buffer int) (*Subscription, error) {
// Subscribe to the event internally
ch := make(chan *types.Header, buffer)
sub, err := ec.client.SubscribeNewHead(ctx.context, ch)
if err != nil {
return nil, err
}
// Start up a dispatcher to feed into the callback
go func() {
for {
select {
case header := <-ch:
handler.OnNewHead(&Header{header})
case err := <-sub.Err():
handler.OnError(err.Error())
return
}
}
}()
return &Subscription{sub}, nil
}
// State Access
// GetBalanceAt returns the wei balance of the given account.
// The block number can be <0, in which case the balance is taken from the latest known block.
func (ec *EthereumClient) GetBalanceAt(ctx *Context, account *Address, number int64) (*BigInt, error) {
if number < 0 {
balance, err := ec.client.BalanceAt(ctx.context, account.address, nil)
return &BigInt{balance}, err
}
balance, err := ec.client.BalanceAt(ctx.context, account.address, big.NewInt(number))
return &BigInt{balance}, err
}
// GetStorageAt returns the value of key in the contract storage of the given account.
// The block number can be <0, in which case the value is taken from the latest known block.
func (ec *EthereumClient) GetStorageAt(ctx *Context, account *Address, key *Hash, number int64) ([]byte, error) {
if number < 0 {
return ec.client.StorageAt(ctx.context, account.address, key.hash, nil)
}
return ec.client.StorageAt(ctx.context, account.address, key.hash, big.NewInt(number))
}
// GetCodeAt returns the contract code of the given account.
// The block number can be <0, in which case the code is taken from the latest known block.
func (ec *EthereumClient) GetCodeAt(ctx *Context, account *Address, number int64) ([]byte, error) {
if number < 0 {
return ec.client.CodeAt(ctx.context, account.address, nil)
}
return ec.client.CodeAt(ctx.context, account.address, big.NewInt(number))
}
// GetNonceAt returns the account nonce of the given account.
// The block number can be <0, in which case the nonce is taken from the latest known block.
func (ec *EthereumClient) GetNonceAt(ctx *Context, account *Address, number int64) (int64, error) {
if number < 0 {
nonce, err := ec.client.NonceAt(ctx.context, account.address, nil)
return int64(nonce), err
}
nonce, err := ec.client.NonceAt(ctx.context, account.address, big.NewInt(number))
return int64(nonce), err
}
// Filters
// FilterLogs executes a filter query.
func (ec *EthereumClient) FilterLogs(ctx *Context, query *FilterQuery) (*Logs, error) {
logs, err := ec.client.FilterLogs(ctx.context, query.query)
if err != nil {
return nil, err
}
// Temp hack due to vm.Logs being []*vm.Log
res := make(vm.Logs, len(logs))
for i, log := range logs {
res[i] = &log
}
return &Logs{res}, nil
}
// FilterLogsHandler is a client-side subscription callback to invoke on events and
// subscription failure.
type FilterLogsHandler interface {
OnFilterLogs(log *Log)
OnError(failure string)
}
// SubscribeFilterLogs subscribes to the results of a streaming filter query.
func (ec *EthereumClient) SubscribeFilterLogs(ctx *Context, query *FilterQuery, handler FilterLogsHandler, buffer int) (*Subscription, error) {
// Subscribe to the event internally
ch := make(chan vm.Log, buffer)
sub, err := ec.client.SubscribeFilterLogs(ctx.context, query.query, ch)
if err != nil {
return nil, err
}
// Start up a dispatcher to feed into the callback
go func() {
for {
select {
case log := <-ch:
handler.OnFilterLogs(&Log{&log})
case err := <-sub.Err():
handler.OnError(err.Error())
return
}
}
}()
return &Subscription{sub}, nil
}
// Pending State
// GetPendingBalanceAt returns the wei balance of the given account in the pending state.
func (ec *EthereumClient) GetPendingBalanceAt(ctx *Context, account *Address) (*BigInt, error) {
balance, err := ec.client.PendingBalanceAt(ctx.context, account.address)
return &BigInt{balance}, err
}
// GetPendingStorageAt returns the value of key in the contract storage of the given account in the pending state.
func (ec *EthereumClient) GetPendingStorageAt(ctx *Context, account *Address, key *Hash) ([]byte, error) {
return ec.client.PendingStorageAt(ctx.context, account.address, key.hash)
}
// GetPendingCodeAt returns the contract code of the given account in the pending state.
func (ec *EthereumClient) GetPendingCodeAt(ctx *Context, account *Address) ([]byte, error) {
return ec.client.PendingCodeAt(ctx.context, account.address)
}
// GetPendingNonceAt returns the account nonce of the given account in the pending state.
// This is the nonce that should be used for the next transaction.
func (ec *EthereumClient) GetPendingNonceAt(ctx *Context, account *Address) (int64, error) {
nonce, err := ec.client.PendingNonceAt(ctx.context, account.address)
return int64(nonce), err
}
// GetPendingTransactionCount returns the total number of transactions in the pending state.
func (ec *EthereumClient) GetPendingTransactionCount(ctx *Context) (int, error) {
count, err := ec.client.PendingTransactionCount(ctx.context)
return int(count), err
}
// Contract Calling
// CallContract executes a message call transaction, which is directly executed in the VM
// of the node, but never mined into the blockchain.
//
// blockNumber selects the block height at which the call runs. It can be <0, in which
// case the code is taken from the latest known block. Note that state from very old
// blocks might not be available.
func (ec *EthereumClient) CallContract(ctx *Context, msg *CallMsg, number int64) ([]byte, error) {
if number < 0 {
return ec.client.CallContract(ctx.context, msg.msg, nil)
}
return ec.client.CallContract(ctx.context, msg.msg, big.NewInt(number))
}
// PendingCallContract executes a message call transaction using the EVM.
// The state seen by the contract call is the pending state.
func (ec *EthereumClient) PendingCallContract(ctx *Context, msg *CallMsg) ([]byte, error) {
return ec.client.PendingCallContract(ctx.context, msg.msg)
}
// SuggestGasPrice retrieves the currently suggested gas price to allow a timely
// execution of a transaction.
func (ec *EthereumClient) SuggestGasPrice(ctx *Context) (*BigInt, error) {
price, err := ec.client.SuggestGasPrice(ctx.context)
return &BigInt{price}, err
}
// EstimateGas tries to estimate the gas needed to execute a specific transaction based on
// the current pending state of the backend blockchain. There is no guarantee that this is
// the true gas limit requirement as other transactions may be added or removed by miners,
// but it should provide a basis for setting a reasonable default.
func (ec *EthereumClient) EstimateGas(ctx *Context, msg *CallMsg) (*BigInt, error) {
price, err := ec.client.EstimateGas(ctx.context, msg.msg)
return &BigInt{price}, err
}
// SendTransaction injects a signed transaction into the pending pool for execution.
//
// If the transaction was a contract creation use the TransactionReceipt method to get the
// contract address after the transaction has been mined.
func (ec *EthereumClient) SendTransaction(ctx *Context, tx *Transaction) error {
return ec.client.SendTransaction(ctx.context, tx.tx)
}
