path: root/internal/ethapi/api.go

// Copyright 2015 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/>.

package ethapi

import (
    "bytes"
    "encoding/hex"
    "encoding/json"
    "fmt"
    "math/big"
    "strings"
    "time"

    "github.com/ethereum/ethash"
    "github.com/ethereum/go-ethereum/accounts"
    "github.com/ethereum/go-ethereum/common"
    "github.com/ethereum/go-ethereum/common/hexutil"
    "github.com/ethereum/go-ethereum/core"
    "github.com/ethereum/go-ethereum/core/types"
    "github.com/ethereum/go-ethereum/core/vm"
    "github.com/ethereum/go-ethereum/crypto"
    "github.com/ethereum/go-ethereum/ethdb"
    "github.com/ethereum/go-ethereum/logger"
    "github.com/ethereum/go-ethereum/logger/glog"
    "github.com/ethereum/go-ethereum/p2p"
    "github.com/ethereum/go-ethereum/rlp"
    "github.com/ethereum/go-ethereum/rpc"
    "github.com/syndtr/goleveldb/leveldb"
    "github.com/syndtr/goleveldb/leveldb/util"
    "golang.org/x/net/context"
)

const defaultGas = uint64(90000)

// PublicEthereumAPI provides an API to access Ethereum related information.
// It offers only methods that operate on public data that is freely available to anyone.
type PublicEthereumAPI struct {
    b Backend
}

// NewPublicEthereumAPI creates a new Etheruem protocol API.
func NewPublicEthereumAPI(b Backend) *PublicEthereumAPI {
    return &PublicEthereumAPI{b}
}

// GasPrice returns a suggestion for a gas price.
func (s *PublicEthereumAPI) GasPrice(ctx context.Context) (*big.Int, error) {
    return s.b.SuggestPrice(ctx)
}

// ProtocolVersion returns the current Ethereum protocol version this node supports
func (s *PublicEthereumAPI) ProtocolVersion() *rpc.HexNumber {
    return rpc.NewHexNumber(s.b.ProtocolVersion())
}

// Syncing returns false in case the node is currently not syncing with the network. It can be up to date or has not
// yet received the latest block headers from its pears. In case it is synchronizing:
// - startingBlock: block number this node started to synchronise from
// - currentBlock:  block number this node is currently importing
// - highestBlock:  block number of the highest block header this node has received from peers
// - pulledStates:  number of state entries processed until now
// - knownStates:   number of known state entries that still need to be pulled
func (s *PublicEthereumAPI) Syncing() (interface{}, error) {
    progress := s.b.Downloader().Progress()

    // Return not syncing if the synchronisation already completed
    if progress.CurrentBlock >= progress.HighestBlock {
        return false, nil
    }
    // Otherwise gather the block sync stats
    return map[string]interface{}{
        "startingBlock": rpc.NewHexNumber(progress.StartingBlock),
        "currentBlock":  rpc.NewHexNumber(progress.CurrentBlock),
        "highestBlock":  rpc.NewHexNumber(progress.HighestBlock),
        "pulledStates":  rpc.NewHexNumber(progress.PulledStates),
        "knownStates":   rpc.NewHexNumber(progress.KnownStates),
    }, nil
}

// PublicTxPoolAPI offers and API for the transaction pool. It only operates on data that is non confidential.
type PublicTxPoolAPI struct {
    b Backend
}

// NewPublicTxPoolAPI creates a new tx pool service that gives information about the transaction pool.
func NewPublicTxPoolAPI(b Backend) *PublicTxPoolAPI {
    return &PublicTxPoolAPI{b}
}

// Content returns the transactions contained within the transaction pool.
func (s *PublicTxPoolAPI) Content() map[string]map[string]map[string]*RPCTransaction {
    content := map[string]map[string]map[string]*RPCTransaction{
        "pending": make(map[string]map[string]*RPCTransaction),
        "queued":  make(map[string]map[string]*RPCTransaction),
    }
    pending, queue := s.b.TxPoolContent()

    // Flatten the pending transactions
    for account, txs := range pending {
        dump := make(map[string]*RPCTransaction)
        for nonce, tx := range txs {
            dump[fmt.Sprintf("%d", nonce)] = newRPCPendingTransaction(tx)
        }
        content["pending"][account.Hex()] = dump
    }
    // Flatten the queued transactions
    for account, txs := range queue {
        dump := make(map[string]*RPCTransaction)
        for nonce, tx := range txs {
            dump[fmt.Sprintf("%d", nonce)] = newRPCPendingTransaction(tx)
        }
        content["queued"][account.Hex()] = dump
    }
    return content
}

// Status returns the number of pending and queued transaction in the pool.
func (s *PublicTxPoolAPI) Status() map[string]*rpc.HexNumber {
    pending, queue := s.b.Stats()
    return map[string]*rpc.HexNumber{
        "pending": rpc.NewHexNumber(pending),
        "queued":  rpc.NewHexNumber(queue),
    }
}

// Inspect retrieves the content of the transaction pool and flattens it into an
// easily inspectable list.
func (s *PublicTxPoolAPI) Inspect() map[string]map[string]map[string]string {
    content := map[string]map[string]map[string]string{
        "pending": make(map[string]map[string]string),
        "queued":  make(map[string]map[string]string),
    }
    pending, queue := s.b.TxPoolContent()

    // Define a formatter to flatten a transaction into a string
    var format = func(tx *types.Transaction) string {
        if to := tx.To(); to != nil {
            return fmt.Sprintf("%s: %v wei + %v × %v gas", tx.To().Hex(), tx.Value(), tx.Gas(), tx.GasPrice())
        }
        return fmt.Sprintf("contract creation: %v wei + %v × %v gas", tx.Value(), tx.Gas(), tx.GasPrice())
    }
    // Flatten the pending transactions
    for account, txs := range pending {
        dump := make(map[string]string)
        for nonce, tx := range txs {
            dump[fmt.Sprintf("%d", nonce)] = format(tx)
        }
        content["pending"][account.Hex()] = dump
    }
    // Flatten the queued transactions
    for account, txs := range queue {
        dump := make(map[string]string)
        for nonce, tx := range txs {
            dump[fmt.Sprintf("%d", nonce)] = format(tx)
        }
        content["queued"][account.Hex()] = dump
    }
    return content
}

// PublicAccountAPI provides an API to access accounts managed by this node.
// It offers only methods that can retrieve accounts.
type PublicAccountAPI struct {
    am *accounts.Manager
}

// NewPublicAccountAPI creates a new PublicAccountAPI.
func NewPublicAccountAPI(am *accounts.Manager) *PublicAccountAPI {
    return &PublicAccountAPI{am: am}
}

// Accounts returns the collection of accounts this node manages
func (s *PublicAccountAPI) Accounts() []accounts.Account {
    return s.am.Accounts()
}

// PrivateAccountAPI provides an API to access accounts managed by this node.
// It offers methods to create, (un)lock en list accounts. Some methods accept
// passwords and are therefore considered private by default.
type PrivateAccountAPI struct {
    am *accounts.Manager
    b  Backend
}

// NewPrivateAccountAPI create a new PrivateAccountAPI.
func NewPrivateAccountAPI(b Backend) *PrivateAccountAPI {
    return &PrivateAccountAPI{
        am: b.AccountManager(),
        b:  b,
    }
}

// ListAccounts will return a list of addresses for accounts this node manages.
func (s *PrivateAccountAPI) ListAccounts() []common.Address {
    accounts := s.am.Accounts()
    addresses := make([]common.Address, len(accounts))
    for i, acc := range accounts {
        addresses[i] = acc.Address
    }
    return addresses
}

// NewAccount will create a new account and returns the address for the new account.
func (s *PrivateAccountAPI) NewAccount(password string) (common.Address, error) {
    acc, err := s.am.NewAccount(password)
    if err == nil {
        return acc.Address, nil
    }
    return common.Address{}, err
}

// ImportRawKey stores the given hex encoded ECDSA key into the key directory,
// encrypting it with the passphrase.
func (s *PrivateAccountAPI) ImportRawKey(privkey string, password string) (common.Address, error) {
    hexkey, err := hex.DecodeString(privkey)
    if err != nil {
        return common.Address{}, err
    }

    acc, err := s.am.ImportECDSA(crypto.ToECDSA(hexkey), password)
    return acc.Address, err
}

// UnlockAccount will unlock the account associated with the given address with
// the given password for duration seconds. If duration is nil it will use a
// default of 300 seconds. It returns an indication if the account was unlocked.
func (s *PrivateAccountAPI) UnlockAccount(addr common.Address, password string, duration *rpc.HexNumber) (bool, error) {
    if duration == nil {
        duration = rpc.NewHexNumber(300)
    }
    a := accounts.Account{Address: addr}
    d := time.Duration(duration.Int64()) * time.Second
    if err := s.am.TimedUnlock(a, password, d); err != nil {
        return false, err
    }
    return true, nil
}

// LockAccount will lock the account associated with the given address when it's unlocked.
func (s *PrivateAccountAPI) LockAccount(addr common.Address) bool {
    return s.am.Lock(addr) == nil
}

// SendTransaction will create a transaction from the given arguments and
// tries to sign it with the key associated with args.To. If the given passwd isn't
// able to decrypt the key it fails.
func (s *PrivateAccountAPI) SendTransaction(ctx context.Context, args SendTxArgs, passwd string) (common.Hash, error) {
    var err error
    args, err = prepareSendTxArgs(ctx, args, s.b)
    if err != nil {
        return common.Hash{}, err
    }

    if args.Nonce == nil {
        nonce, err := s.b.GetPoolNonce(ctx, args.From)
        if err != nil {
            return common.Hash{}, err
        }
        args.Nonce = rpc.NewHexNumber(nonce)
    }

    var tx *types.Transaction
    if args.To == nil {
        tx = types.NewContractCreation(args.Nonce.Uint64(), args.Value.BigInt(), args.Gas.BigInt(), args.GasPrice.BigInt(), common.FromHex(args.Data))
    } else {
        tx = types.NewTransaction(args.Nonce.Uint64(), *args.To, args.Value.BigInt(), args.Gas.BigInt(), args.GasPrice.BigInt(), common.FromHex(args.Data))
    }

    signer := types.MakeSigner(s.b.ChainConfig(), s.b.CurrentBlock().Number())
    signature, err := s.am.SignWithPassphrase(args.From, passwd, signer.Hash(tx).Bytes())
    if err != nil {
        return common.Hash{}, err
    }

    return submitTransaction(ctx, s.b, tx, signature)
}

// signHash is a helper function that calculates a hash for the given message that can be
// safely used to calculate a signature from.
//
// The hash is calulcated as
//   keccak256("\x19Ethereum Signed Message:\n"${message length}${message}).
//
// This gives context to the signed message and prevents signing of transactions.
func signHash(data []byte) []byte {
    msg := fmt.Sprintf("\x19Ethereum Signed Message:\n%d%s", len(data), data)
    return crypto.Keccak256([]byte(msg))
}

// Sign calculates an Ethereum ECDSA signature for:
// keccack256("\x19Ethereum Signed Message:\n" + len(message) + message))
//
// The key used to calculate the signature is decrypted with the given password.
//
// https://github.com/ethereum/go-ethereum/wiki/Management-APIs#personal_sign
func (s *PrivateAccountAPI) Sign(ctx context.Context, data hexutil.Bytes, addr common.Address, passwd string) (hexutil.Bytes, error) {
    return s.b.AccountManager().SignWithPassphrase(addr, passwd, signHash(data))
}

// EcRecover returns the address for the account that was used to create the signature.
// Note, this function is compatible with eth_sign and personal_sign. As such it recovers
// the address of:
// hash = keccak256("\x19Ethereum Signed Message:\n"${message length}${message})
// addr = ecrecover(hash, signature)
//
// https://github.com/ethereum/go-ethereum/wiki/Management-APIs#personal_ecRecover
func (s *PrivateAccountAPI) EcRecover(ctx context.Context, data, sig hexutil.Bytes) (common.Address, error) {
    if len(sig) != 65 {
        return common.Address{}, fmt.Errorf("signature must be 65 bytes long")
    }
    // see crypto.Ecrecover description
    if sig[64] == 27 || sig[64] == 28 {
        sig[64] -= 27
    }
    rpk, err := crypto.Ecrecover(signHash(data), sig)
    if err != nil {
        return common.Address{}, err
    }
    pubKey := crypto.ToECDSAPub(rpk)
    recoveredAddr := crypto.PubkeyToAddress(*pubKey)
    return recoveredAddr, nil
}

// SignAndSendTransaction was renamed to SendTransaction. This method is deprecated
// and will be removed in the future. It primary goal is to give clients time to update.
func (s *PrivateAccountAPI) SignAndSendTransaction(ctx context.Context, args SendTxArgs, passwd string) (common.Hash, error) {
    return s.SendTransaction(ctx, args, passwd)
}

// PublicBlockChainAPI provides an API to access the Ethereum blockchain.
// It offers only methods that operate on public data that is freely available to anyone.
type PublicBlockChainAPI struct {
    b Backend
}

// NewPublicBlockChainAPI creates a new Etheruem blockchain API.
func NewPublicBlockChainAPI(b Backend) *PublicBlockChainAPI {
    return &PublicBlockChainAPI{b}
}

// BlockNumber returns the block number of the chain head.
func (s *PublicBlockChainAPI) BlockNumber() *big.Int {
    header, _ := s.b.HeaderByNumber(context.Background(), rpc.LatestBlockNumber) // latest header should always be available
    return header.Number
}

// GetBalance returns the amount of wei for the given address in the state of the
// given block number. The rpc.LatestBlockNumber and rpc.PendingBlockNumber meta
// block numbers are also allowed.
func (s *PublicBlockChainAPI) GetBalance(ctx context.Context, address common.Address, blockNr rpc.BlockNumber) (*big.Int, error) {
    state, _, err := s.b.StateAndHeaderByNumber(ctx, blockNr)
    if state == nil || err != nil {
        return nil, err
    }

    return state.GetBalance(ctx, address)
}

// GetBlockByNumber returns the requested block. When blockNr is -1 the chain head is returned. When fullTx is true all
// transactions in the block are returned in full detail, otherwise only the transaction hash is returned.
func (s *PublicBlockChainAPI) GetBlockByNumber(ctx context.Context, blockNr rpc.BlockNumber, fullTx bool) (map[string]interface{}, error) {
    block, err := s.b.BlockByNumber(ctx, blockNr)
    if block != nil {
        response, err := s.rpcOutputBlock(block, true, fullTx)
        if err == nil && blockNr == rpc.PendingBlockNumber {
            // Pending blocks need to nil out a few fields
            for _, field := range []string{"hash", "nonce", "logsBloom", "miner"} {
                response[field] = nil
            }
        }
        return response, err
    }
    return nil, err
}

// GetBlockByHash returns the requested block. When fullTx is true all transactions in the block are returned in full
// detail, otherwise only the transaction hash is returned.
func (s *PublicBlockChainAPI) GetBlockByHash(ctx context.Context, blockHash common.Hash, fullTx bool) (map[string]interface{}, error) {
    block, err := s.b.GetBlock(ctx, blockHash)
    if block != nil {
        return s.rpcOutputBlock(block, true, fullTx)
    }
    return nil, err
}

// GetUncleByBlockNumberAndIndex returns the uncle block for the given block hash and index. When fullTx is true
// all transactions in the block are returned in full detail, otherwise only the transaction hash is returned.
func (s *PublicBlockChainAPI) GetUncleByBlockNumberAndIndex(ctx context.Context, blockNr rpc.BlockNumber, index rpc.HexNumber) (map[string]interface{}, error) {
    block, err := s.b.BlockByNumber(ctx, blockNr)
    if block != nil {
        uncles := block.Uncles()
        if index.Int() < 0 || index.Int() >= len(uncles) {
            glog.V(logger.Debug).Infof("uncle block on index %d not found for block #%d", index.Int(), blockNr)
            return nil, nil
        }
        block = types.NewBlockWithHeader(uncles[index.Int()])
        return s.rpcOutputBlock(block, false, false)
    }
    return nil, err
}

// GetUncleByBlockHashAndIndex returns the uncle block for the given block hash and index. When fullTx is true
// all transactions in the block are returned in full detail, otherwise only the transaction hash is returned.
func (s *PublicBlockChainAPI) GetUncleByBlockHashAndIndex(ctx context.Context, blockHash common.Hash, index rpc.HexNumber) (map[string]interface{}, error) {
    block, err := s.b.GetBlock(ctx, blockHash)
    if block != nil {
        uncles := block.Uncles()
        if index.Int() < 0 || index.Int() >= len(uncles) {
            glog.V(logger.Debug).Infof("uncle block on index %d not found for block %s", index.Int(), blockHash.Hex())
            return nil, nil
        }
        block = types.NewBlockWithHeader(uncles[index.Int()])
        return s.rpcOutputBlock(block, false, false)
    }
    return nil, err
}

// GetUncleCountByBlockNumber returns number of uncles in the block for the given block number
func (s *PublicBlockChainAPI) GetUncleCountByBlockNumber(ctx context.Context, blockNr rpc.BlockNumber) *rpc.HexNumber {
    if block, _ := s.b.BlockByNumber(ctx, blockNr); block != nil {
        return rpc.NewHexNumber(len(block.Uncles()))
    }
    return nil
}

// GetUncleCountByBlockHash returns number of uncles in the block for the given block hash
func (s *PublicBlockChainAPI) GetUncleCountByBlockHash(ctx context.Context, blockHash common.Hash) *rpc.HexNumber {
    if block, _ := s.b.GetBlock(ctx, blockHash); block != nil {
        return rpc.NewHexNumber(len(block.Uncles()))
    }
    return nil
}

// GetCode returns the code stored at the given address in the state for the given block number.
func (s *PublicBlockChainAPI) GetCode(ctx context.Context, address common.Address, blockNr rpc.BlockNumber) (string, error) {
    state, _, err := s.b.StateAndHeaderByNumber(ctx, blockNr)
    if state == nil || err != nil {
        return "", err
    }
    res, err := state.GetCode(ctx, address)
    if len(res) == 0 || err != nil { // backwards compatibility
        return "0x", err
    }
    return common.ToHex(res), nil
}

// GetStorageAt returns the storage from the state at the given address, key and
// block number. The rpc.LatestBlockNumber and rpc.PendingBlockNumber meta block
// numbers are also allowed.
func (s *PublicBlockChainAPI) GetStorageAt(ctx context.Context, address common.Address, key string, blockNr rpc.BlockNumber) (string, error) {
    state, _, err := s.b.StateAndHeaderByNumber(ctx, blockNr)
    if state == nil || err != nil {
        return "0x", err
    }
    res, err := state.GetState(ctx, address, common.HexToHash(key))
    if err != nil {
        return "0x", err
    }
    return res.Hex(), nil
}

// callmsg is the message type used for call transations.
type callmsg struct {
    addr          common.Address
    to            *common.Address
    gas, gasPrice *big.Int
    value         *big.Int
    data          []byte
}

// accessor boilerplate to implement core.Message
func (m callmsg) From() (common.Address, error)         { return m.addr, nil }
func (m callmsg) FromFrontier() (common.Address, error) { return m.addr, nil }
func (m callmsg) Nonce() uint64                         { return 0 }
func (m callmsg) CheckNonce() bool                      { return false }
func (m callmsg) To() *common.Address                   { return m.to }
func (m callmsg) GasPrice() *big.Int                    { return m.gasPrice }
func (m callmsg) Gas() *big.Int                         { return m.gas }
func (m callmsg) Value() *big.Int                       { return m.value }
func (m callmsg) Data() []byte                          { return m.data }

// CallArgs represents the arguments for a call.
type CallArgs struct {
    From     common.Address  `json:"from"`
    To       *common.Address `json:"to"`
    Gas      rpc.HexNumber   `json:"gas"`
    GasPrice rpc.HexNumber   `json:"gasPrice"`
    Value    rpc.HexNumber   `json:"value"`
    Data     string          `json:"data"`
}

func (s *PublicBlockChainAPI) doCall(ctx context.Context, args CallArgs, blockNr rpc.BlockNumber) (string, *big.Int, error) {
    defer func(start time.Time) { glog.V(logger.Debug).Infof("call took %v", time.Since(start)) }(time.Now())

    state, header, err := s.b.StateAndHeaderByNumber(ctx, blockNr)
    if state == nil || err != nil {
        return "0x", common.Big0, err
    }

    // Set the account address to interact with
    var addr common.Address
    if args.From == (common.Address{}) {
        accounts := s.b.AccountManager().Accounts()
        if len(accounts) == 0 {
            addr = common.Address{}
        } else {
            addr = accounts[0].Address
        }
    } else {
        addr = args.From
    }

    // Assemble the CALL invocation
    gas, gasPrice := args.Gas.BigInt(), args.GasPrice.BigInt()
    if gas.Cmp(common.Big0) == 0 {
        gas = big.NewInt(50000000)
    }
    if gasPrice.Cmp(common.Big0) == 0 {
        gasPrice = new(big.Int).Mul(big.NewInt(50), common.Shannon)
    }
    msg := types.NewMessage(addr, args.To, 0, args.Value.BigInt(), gas, gasPrice, common.FromHex(args.Data), false)

    // Execute the call and return
    vmenv, vmError, err := s.b.GetVMEnv(ctx, msg, state, header)
    if err != nil {
        return "0x", common.Big0, err
    }
    gp := new(core.GasPool).AddGas(common.MaxBig)
    res, gas, err := core.ApplyMessage(vmenv, msg, gp)
    if err := vmError(); err != nil {
        return "0x", common.Big0, err
    }
    if len(res) == 0 { // backwards compatability
        return "0x", gas, err
    }
    return common.ToHex(res), gas, err
}

// Call executes the given transaction on the state for the given block number.
// It doesn't make and changes in the state/blockchain and is usefull to execute and retrieve values.
func (s *PublicBlockChainAPI) Call(ctx context.Context, args CallArgs, blockNr rpc.BlockNumber) (string, error) {
    result, _, err := s.doCall(ctx, args, blockNr)
    return result, err
}

// EstimateGas returns an estimate of the amount of gas needed to execute the given transaction.
func (s *PublicBlockChainAPI) EstimateGas(ctx context.Context, args CallArgs) (*rpc.HexNumber, error) {
    _, gas, err := s.doCall(ctx, args, rpc.PendingBlockNumber)
    return rpc.NewHexNumber(gas), err
}

// ExecutionResult groups all structured logs emitted by the EVM
// while replaying a transaction in debug mode as well as the amount of
// gas used and the return value
type ExecutionResult struct {
    Gas         *big.Int       `json:"gas"`
    ReturnValue string         `json:"returnValue"`
    StructLogs  []StructLogRes `json:"structLogs"`
}

// StructLogRes stores a structured log emitted by the EVM while replaying a
// transaction in debug mode
type StructLogRes struct {
    Pc      uint64            `json:"pc"`
    Op      string            `json:"op"`
    Gas     *big.Int          `json:"gas"`
    GasCost *big.Int          `json:"gasCost"`
    Depth   int               `json:"depth"`
    Error   error             `json:"error"`
    Stack   []string          `json:"stack"`
    Memory  []string          `json:"memory"`
    Storage map[string]string `json:"storage"`
}

// formatLogs formats EVM returned structured logs for json output
func FormatLogs(structLogs []vm.StructLog) []StructLogRes {
    formattedStructLogs := make([]StructLogRes, len(structLogs))
    for index, trace := range structLogs {
        formattedStructLogs[index] = StructLogRes{
            Pc:      trace.Pc,
            Op:      trace.Op.String(),
            Gas:     trace.Gas,
            GasCost: trace.GasCost,
            Depth:   trace.Depth,
            Error:   trace.Err,
            Stack:   make([]string, len(trace.Stack)),
            Storage: make(map[string]string),
        }

        for i, stackValue := range trace.Stack {
            formattedStructLogs[index].Stack[i] = fmt.Sprintf("%x", common.LeftPadBytes(stackValue.Bytes(), 32))
        }

        for i := 0; i+32 <= len(trace.Memory); i += 32 {
            formattedStructLogs[index].Memory = append(formattedStructLogs[index].Memory, fmt.Sprintf("%x", trace.Memory[i:i+32]))
        }

        for i, storageValue := range trace.Storage {
            formattedStructLogs[index].Storage[fmt.Sprintf("%x", i)] = fmt.Sprintf("%x", storageValue)
        }
    }
    return formattedStructLogs
}

// rpcOutputBlock converts the given block to the RPC output which depends on fullTx. If inclTx is true transactions are
// returned. When fullTx is true the returned block contains full transaction details, otherwise it will only contain
// transaction hashes.
func (s *PublicBlockChainAPI) rpcOutputBlock(b *types.Block, inclTx bool, fullTx bool) (map[string]interface{}, error) {
    head := b.Header() // copies the header once
    fields := map[string]interface{}{
        "number":           rpc.NewHexNumber(head.Number),
        "hash":             b.Hash(),
        "parentHash":       head.ParentHash,
        "nonce":            head.Nonce,
        "mixHash":          head.MixDigest,
        "sha3Uncles":       head.UncleHash,
        "logsBloom":        head.Bloom,
        "stateRoot":        head.Root,
        "miner":            head.Coinbase,
        "difficulty":       rpc.NewHexNumber(head.Difficulty),
        "totalDifficulty":  rpc.NewHexNumber(s.b.GetTd(b.Hash())),
        "extraData":        hexutil.Bytes(head.Extra),
        "size":             rpc.NewHexNumber(b.Size().Int64()),
        "gasLimit":         rpc.NewHexNumber(head.GasLimit),
        "gasUsed":          rpc.NewHexNumber(head.GasUsed),
        "timestamp":        rpc.NewHexNumber(head.Time),
        "transactionsRoot": head.TxHash,
        "receiptsRoot":     head.ReceiptHash,
    }

    if inclTx {
        formatTx := func(tx *types.Transaction) (interface{}, error) {
            return tx.Hash(), nil
        }

        if fullTx {
            formatTx = func(tx *types.Transaction) (interface{}, error) {
                return newRPCTransaction(b, tx.Hash())
            }
        }

        txs := b.Transactions()
        transactions := make([]interface{}, len(txs))
        var err error
        for i, tx := range b.Transactions() {
            if transactions[i], err = formatTx(tx); err != nil {
                return nil, err
            }
        }
        fields["transactions"] = transactions
    }

    uncles := b.Uncles()
    uncleHashes := make([]common.Hash, len(uncles))
    for i, uncle := range uncles {
        uncleHashes[i] = uncle.Hash()
    }
    fields["uncles"] = uncleHashes

    return fields, nil
}

// RPCTransaction represents a transaction that will serialize to the RPC representation of a transaction
type RPCTransaction struct {
    BlockHash        common.Hash     `json:"blockHash"`
    BlockNumber      *rpc.HexNumber  `json:"blockNumber"`
    From             common.Address  `json:"from"`
    Gas              *rpc.HexNumber  `json:"gas"`
    GasPrice         *rpc.HexNumber  `json:"gasPrice"`
    Hash             common.Hash     `json:"hash"`
    Input            hexutil.Bytes   `json:"input"`
    Nonce            *rpc.HexNumber  `json:"nonce"`
    To               *common.Address `json:"to"`
    TransactionIndex *rpc.HexNumber  `json:"transactionIndex"`
    Value            *rpc.HexNumber  `json:"value"`
    V                *rpc.HexNumber  `json:"v"`
    R                *rpc.HexNumber  `json:"r"`
    S                *rpc.HexNumber  `json:"s"`
}

// newRPCPendingTransaction returns a pending transaction that will serialize to the RPC representation
func newRPCPendingTransaction(tx *types.Transaction) *RPCTransaction {
    var signer types.Signer = types.FrontierSigner{}
    if tx.Protected() {
        signer = types.NewEIP155Signer(tx.ChainId())
    }
    from, _ := types.Sender(signer, tx)
    v, r, s := types.SignatureValues(signer, tx)
    return &RPCTransaction{
        From:     from,
        Gas:      rpc.NewHexNumber(tx.Gas()),
        GasPrice: rpc.NewHexNumber(tx.GasPrice()),
        Hash:     tx.Hash(),
        Input:    hexutil.Bytes(tx.Data()),
        Nonce:    rpc.NewHexNumber(tx.Nonce()),
        To:       tx.To(),
        Value:    rpc.NewHexNumber(tx.Value()),
        V:        rpc.NewHexNumber(v),
        R:        rpc.NewHexNumber(r),
        S:        rpc.NewHexNumber(s),
    }
}

// newRPCTransaction returns a transaction that will serialize to the RPC representation.
func newRPCTransactionFromBlockIndex(b *types.Block, txIndex int) (*RPCTransaction, error) {
    if txIndex >= 0 && txIndex < len(b.Transactions()) {
        tx := b.Transactions()[txIndex]
        var signer types.Signer = types.FrontierSigner{}
        if tx.Protected() {
            signer = types.NewEIP155Signer(tx.ChainId())
        }
        from, _ := types.Sender(signer, tx)
        v, r, s := tx.RawSignatureValues()
        return &RPCTransaction{
            BlockHash:        b.Hash(),
            BlockNumber:      rpc.NewHexNumber(b.Number()),
            From:             from,
            Gas:              rpc.NewHexNumber(tx.Gas()),
            GasPrice:         rpc.NewHexNumber(tx.GasPrice()),
            Hash:             tx.Hash(),
            Input:            hexutil.Bytes(tx.Data()),
            Nonce:            rpc.NewHexNumber(tx.Nonce()),
            To:               tx.To(),
            TransactionIndex: rpc.NewHexNumber(txIndex),
            Value:            rpc.NewHexNumber(tx.Value()),
            V:                rpc.NewHexNumber(v),
            R:                rpc.NewHexNumber(r),
            S:                rpc.NewHexNumber(s),
        }, nil
    }

    return nil, nil
}

// newRPCRawTransactionFromBlockIndex returns the bytes of a transaction given a block and a transaction index.
func newRPCRawTransactionFromBlockIndex(b *types.Block, txIndex int) (hexutil.Bytes, error) {
    if txIndex >= 0 && txIndex < len(b.Transactions()) {
        tx := b.Transactions()[txIndex]
        return rlp.EncodeToBytes(tx)
    }

    return nil, nil
}

// newRPCTransaction returns a transaction that will serialize to the RPC representation.
func newRPCTransaction(b *types.Block, txHash common.Hash) (*RPCTransaction, error) {
    for idx, tx := range b.Transactions() {
        if tx.Hash() == txHash {
            return newRPCTransactionFromBlockIndex(b, idx)
        }
    }

    return nil, nil
}

// PublicTransactionPoolAPI exposes methods for the RPC interface
type PublicTransactionPoolAPI struct {
    b Backend
}

// NewPublicTransactionPoolAPI creates a new RPC service with methods specific for the transaction pool.
func NewPublicTransactionPoolAPI(b Backend) *PublicTransactionPoolAPI {
    return &PublicTransactionPoolAPI{b}
}

func getTransaction(chainDb ethdb.Database, b Backend, txHash common.Hash) (*types.Transaction, bool, error) {
    txData, err := chainDb.Get(txHash.Bytes())
    isPending := false
    tx := new(types.Transaction)

    if err == nil && len(txData) > 0 {
        if err := rlp.DecodeBytes(txData, tx); err != nil {
            return nil, isPending, err
        }
    } else {
        // pending transaction?
        tx = b.GetPoolTransaction(txHash)
        isPending = true
    }

    return tx, isPending, nil
}

// GetBlockTransactionCountByNumber returns the number of transactions in the block with the given block number.
func (s *PublicTransactionPoolAPI) GetBlockTransactionCountByNumber(ctx context.Context, blockNr rpc.BlockNumber) *rpc.HexNumber {
    if block, _ := s.b.BlockByNumber(ctx, blockNr); block != nil {
        return rpc.NewHexNumber(len(block.Transactions()))
    }
    return nil
}

// GetBlockTransactionCountByHash returns the number of transactions in the block with the given hash.
func (s *PublicTransactionPoolAPI) GetBlockTransactionCountByHash(ctx context.Context, blockHash common.Hash) *rpc.HexNumber {
    if block, _ := s.b.GetBlock(ctx, blockHash); block != nil {
        return rpc.NewHexNumber(len(block.Transactions()))
    }
    return nil
}

// GetTransactionByBlockNumberAndIndex returns the transaction for the given block number and index.
func (s *PublicTransactionPoolAPI) GetTransactionByBlockNumberAndIndex(ctx context.Context, blockNr rpc.BlockNumber, index rpc.HexNumber) (*RPCTransaction, error) {
    if block, _ := s.b.BlockByNumber(ctx, blockNr); block != nil {
        return newRPCTransactionFromBlockIndex(block, index.Int())
    }
    return nil, nil
}

// GetTransactionByBlockHashAndIndex returns the transaction for the given block hash and index.
func (s *PublicTransactionPoolAPI) GetTransactionByBlockHashAndIndex(ctx context.Context, blockHash common.Hash, index rpc.HexNumber) (*RPCTransaction, error) {
    if block, _ := s.b.GetBlock(ctx, blockHash); block != nil {
        return newRPCTransactionFromBlockIndex(block, index.Int())
    }
    return nil, nil
}

// GetRawTransactionByBlockNumberAndIndex returns the bytes of the transaction for the given block number and index.
func (s *PublicTransactionPoolAPI) GetRawTransactionByBlockNumberAndIndex(ctx context.Context, blockNr rpc.BlockNumber, index rpc.HexNumber) (hexutil.Bytes, error) {
    if block, _ := s.b.BlockByNumber(ctx, blockNr); block != nil {
        return newRPCRawTransactionFromBlockIndex(block, index.Int())
    }
    return nil, nil
}

// GetRawTransactionByBlockHashAndIndex returns the bytes of the transaction for the given block hash and index.
func (s *PublicTransactionPoolAPI) GetRawTransactionByBlockHashAndIndex(ctx context.Context, blockHash common.Hash, index rpc.HexNumber) (hexutil.Bytes, error) {
    if block, _ := s.b.GetBlock(ctx, blockHash); block != nil {
        return newRPCRawTransactionFromBlockIndex(block, index.Int())
    }
    return nil, nil
}

// GetTransactionCount returns the number of transactions the given address has sent for the given block number
func (s *PublicTransactionPoolAPI) GetTransactionCount(ctx context.Context, address common.Address, blockNr rpc.BlockNumber) (*rpc.HexNumber, error) {
    state, _, err := s.b.StateAndHeaderByNumber(ctx, blockNr)
    if state == nil || err != nil {
        return nil, err
    }
    nonce, err := state.GetNonce(ctx, address)
    if err != nil {
        return nil, err
    }
    return rpc.NewHexNumber(nonce), nil
}

// getTransactionBlockData fetches the meta data for the given transaction from the chain database. This is useful to
// retrieve block information for a hash. It returns the block hash, block index and transaction index.
func getTransactionBlockData(chainDb ethdb.Database, txHash common.Hash) (common.Hash, uint64, uint64, error) {
    var txBlock struct {
        BlockHash  common.Hash
        BlockIndex uint64
        Index      uint64
    }

    blockData, err := chainDb.Get(append(txHash.Bytes(), 0x0001))
    if err != nil {
        return common.Hash{}, uint64(0), uint64(0), err
    }

    reader := bytes.NewReader(blockData)
    if err = rlp.Decode(reader, &txBlock); err != nil {
        return common.Hash{}, uint64(0), uint64(0), err
    }

    return txBlock.BlockHash, txBlock.BlockIndex, txBlock.Index, nil
}

// GetTransactionByHash returns the transaction for the given hash
func (s *PublicTransactionPoolAPI) GetTransactionByHash(ctx context.Context, txHash common.Hash) (*RPCTransaction, error) {
    var tx *types.Transaction
    var isPending bool
    var err error

    if tx, isPending, err = getTransaction(s.b.ChainDb(), s.b, txHash); err != nil {
        glog.V(logger.Debug).Infof("%v\n", err)
        return nil, nil
    } else if tx == nil {
        return nil, nil
    }

    if isPending {
        return newRPCPendingTransaction(tx), nil
    }

    blockHash, _, _, err := getTransactionBlockData(s.b.ChainDb(), txHash)
    if err != nil {
        glog.V(logger.Debug).Infof("%v\n", err)
        return nil, nil
    }

    if block, _ := s.b.GetBlock(ctx, blockHash); block != nil {
        return newRPCTransaction(block, txHash)
    }

    return nil, nil
}

// GetRawTransactionByHash returns the bytes of the transaction for the given hash.
func (s *PublicTransactionPoolAPI) GetRawTransactionByHash(ctx context.Context, txHash common.Hash) (hexutil.Bytes, error) {
    var tx *types.Transaction
    var err error

    if tx, _, err = getTransaction(s.b.ChainDb(), s.b, txHash); err != nil {
        glog.V(logger.Debug).Infof("%v\n", err)
        return nil, nil
    } else if tx == nil {
        return nil, nil
    }

    return rlp.EncodeToBytes(tx)
}

// GetTransactionReceipt returns the transaction receipt for the given transaction hash.
func (s *PublicTransactionPoolAPI) GetTransactionReceipt(txHash common.Hash) (map[string]interface{}, error) {
    receipt := core.GetReceipt(s.b.ChainDb(), txHash)
    if receipt == nil {
        glog.V(logger.Debug).Infof("receipt not found for transaction %s", txHash.Hex())
        return nil, nil
    }

    tx, _, err := getTransaction(s.b.ChainDb(), s.b, txHash)
    if err != nil {
        glog.V(logger.Debug).Infof("%v\n", err)
        return nil, nil
    }

    txBlock, blockIndex, index, err := getTransactionBlockData(s.b.ChainDb(), txHash)
    if err != nil {
        glog.V(logger.Debug).Infof("%v\n", err)
        return nil, nil
    }

    var signer types.Signer = types.FrontierSigner{}
    if tx.Protected() {
        signer = types.NewEIP155Signer(tx.ChainId())
    }
    from, _ := types.Sender(signer, tx)

    fields := map[string]interface{}{
        "root":              hexutil.Bytes(receipt.PostState),
        "blockHash":         txBlock,
        "blockNumber":       rpc.NewHexNumber(blockIndex),
        "transactionHash":   txHash,
        "transactionIndex":  rpc.NewHexNumber(index),
        "from":              from,
        "to":                tx.To(),
        "gasUsed":           rpc.NewHexNumber(receipt.GasUsed),
        "cumulativeGasUsed": rpc.NewHexNumber(receipt.CumulativeGasUsed),
        "contractAddress":   nil,
        "logs":              receipt.Logs,
        "logsBloom":         receipt.Bloom,
    }
    if receipt.Logs == nil {
        fields["logs"] = []vm.Logs{}
    }
    // If the ContractAddress is 20 0x0 bytes, assume it is not a contract creation
    if receipt.ContractAddress != (common.Address{}) {
        fields["contractAddress"] = receipt.ContractAddress
    }
    return fields, nil
}

// sign is a helper function that signs a transaction with the private key of the given address.
func (s *PublicTransactionPoolAPI) sign(addr common.Address, tx *types.Transaction) (*types.Transaction, error) {
    signer := types.MakeSigner(s.b.ChainConfig(), s.b.CurrentBlock().Number())

    signature, err := s.b.AccountManager().SignEthereum(addr, signer.Hash(tx).Bytes())
    if err != nil {
        return nil, err
    }
    return tx.WithSignature(signer, signature)
}

// SendTxArgs represents the arguments to sumbit a new transaction into the transaction pool.
type SendTxArgs struct {
    From     common.Address  `json:"from"`
    To       *common.Address `json:"to"`
    Gas      *rpc.HexNumber  `json:"gas"`
    GasPrice *rpc.HexNumber  `json:"gasPrice"`
    Value    *rpc.HexNumber  `json:"value"`
    Data     string          `json:"data"`
    Nonce    *rpc.HexNumber  `json:"nonce"`
}

// prepareSendTxArgs is a helper function that fills in default values for unspecified tx fields.
func prepareSendTxArgs(ctx context.Context, args SendTxArgs, b Backend) (SendTxArgs, error) {
    if args.Gas == nil {
        args.Gas = rpc.NewHexNumber(defaultGas)
    }
    if args.GasPrice == nil {
        price, err := b.SuggestPrice(ctx)
        if err != nil {
            return args, err
        }
        args.GasPrice = rpc.NewHexNumber(price)
    }
    if args.Value == nil {
        args.Value = rpc.NewHexNumber(0)
    }
    return args, nil
}

// submitTransaction is a helper function that submits tx to txPool and creates a log entry.
func submitTransaction(ctx context.Context, b Backend, tx *types.Transaction, signature []byte) (common.Hash, error) {
    signer := types.MakeSigner(b.ChainConfig(), b.CurrentBlock().Number())

    signedTx, err := tx.WithSignature(signer, signature)
    if err != nil {
        return common.Hash{}, err
    }

    if err := b.SendTx(ctx, signedTx); err != nil {
        return common.Hash{}, err
    }

    if signedTx.To() == nil {
        from, _ := types.Sender(signer, signedTx)
        addr := crypto.CreateAddress(from, signedTx.Nonce())
        glog.V(logger.Info).Infof("Tx(%s) created: %s\n", signedTx.Hash().Hex(), addr.Hex())
    } else {
        glog.V(logger.Info).Infof("Tx(%s) to: %s\n", signedTx.Hash().Hex(), tx.To().Hex())
    }

    return signedTx.Hash(), nil
}

// SendTransaction creates a transaction for the given argument, sign it and submit it to the
// transaction pool.
func (s *PublicTransactionPoolAPI) SendTransaction(ctx context.Context, args SendTxArgs) (common.Hash, error) {
    var err error
    args, err = prepareSendTxArgs(ctx, args, s.b)
    if err != nil {
        return common.Hash{}, err
    }

    if args.Nonce == nil {
        nonce, err := s.b.GetPoolNonce(ctx, args.From)
        if err != nil {
            return common.Hash{}, err
        }
        args.Nonce = rpc.NewHexNumber(nonce)
    }

    var tx *types.Transaction
    if args.To == nil {
        tx = types.NewContractCreation(args.Nonce.Uint64(), args.Value.BigInt(), args.Gas.BigInt(), args.GasPrice.BigInt(), common.FromHex(args.Data))
    } else {
        tx = types.NewTransaction(args.Nonce.Uint64(), *args.To, args.Value.BigInt(), args.Gas.BigInt(), args.GasPrice.BigInt(), common.FromHex(args.Data))
    }

    signer := types.MakeSigner(s.b.ChainConfig(), s.b.CurrentBlock().Number())
    signature, err := s.b.AccountManager().SignEthereum(args.From, signer.Hash(tx).Bytes())
    if err != nil {
        return common.Hash{}, err
    }

    return submitTransaction(ctx, s.b, tx, signature)
}

// SendRawTransaction will add the signed transaction to the transaction pool.
// The sender is responsible for signing the transaction and using the correct nonce.
func (s *PublicTransactionPoolAPI) SendRawTransaction(ctx context.Context, encodedTx string) (string, error) {
    tx := new(types.Transaction)
    if err := rlp.DecodeBytes(common.FromHex(encodedTx), tx); err != nil {
        return "", err
    }

    if err := s.b.SendTx(ctx, tx); err != nil {
        return "", err
    }

    signer := types.MakeSigner(s.b.ChainConfig(), s.b.CurrentBlock().Number())
    if tx.To() == nil {
        from, err := types.Sender(signer, tx)
        if err != nil {
            return "", err
        }
        addr := crypto.CreateAddress(from, tx.Nonce())
        glog.V(logger.Info).Infof("Tx(%x) created: %x\n", tx.Hash(), addr)
    } else {
        glog.V(logger.Info).Infof("Tx(%x) to: %x\n", tx.Hash(), tx.To())
    }

    return tx.Hash().Hex(), nil
}

// Sign calculates an ECDSA signature for:
// keccack256("\x19Ethereum Signed Message:\n" + len(message) + message).
//
// The account associated with addr must be unlocked.
//
// https://github.com/ethereum/wiki/wiki/JSON-RPC#eth_sign
func (s *PublicTransactionPoolAPI) Sign(addr common.Address, data hexutil.Bytes) (hexutil.Bytes, error) {
    return s.b.AccountManager().SignEthereum(addr, signHash(data))
}

// SignTransactionArgs represents the arguments to sign a transaction.
type SignTransactionArgs struct {
    From     common.Address
    To       *common.Address
    Nonce    *rpc.HexNumber
    Value    *rpc.HexNumber
    Gas      *rpc.HexNumber
    GasPrice *rpc.HexNumber
    Data     string

    BlockNumber int64
}

// Tx is a helper object for argument and return values
type Tx struct {
    tx *types.Transaction

    To       *common.Address `json:"to"`
    From     common.Address  `json:"from"`
    Nonce    *rpc.HexNumber  `json:"nonce"`
    Value    *rpc.HexNumber  `json:"value"`
    Data     string          `json:"data"`
    GasLimit *rpc.HexNumber  `json:"gas"`
    GasPrice *rpc.HexNumber  `json:"gasPrice"`
    Hash     common.Hash     `json:"hash"`
}

// UnmarshalJSON parses JSON data into tx.
func (tx *Tx) UnmarshalJSON(b []byte) (err error) {
    req := struct {
        To       *common.Address `json:"to"`
        From     common.Address  `json:"from"`
        Nonce    *rpc.HexNumber  `json:"nonce"`
        Value    *rpc.HexNumber  `json:"value"`
        Data     string          `json:"data"`
        GasLimit *rpc.HexNumber  `json:"gas"`
        GasPrice *rpc.HexNumber  `json:"gasPrice"`
        Hash     common.Hash     `json:"hash"`
    }{}

    if err := json.Unmarshal(b, &req); err != nil {
        return err
    }

    tx.To = req.To
    tx.From = req.From
    tx.Nonce = req.Nonce
    tx.Value = req.Value
    tx.Data = req.Data
    tx.GasLimit = req.GasLimit
    tx.GasPrice = req.GasPrice
    tx.Hash = req.Hash

    data := common.Hex2Bytes(tx.Data)

    if tx.Nonce == nil {
        return fmt.Errorf("need nonce")
    }
    if tx.Value == nil {
        tx.Value = rpc.NewHexNumber(0)
    }
    if tx.GasLimit == nil {
        tx.GasLimit = rpc.NewHexNumber(0)
    }
    if tx.GasPrice == nil {
        tx.GasPrice = rpc.NewHexNumber(int64(50000000000))
    }

    if req.To == nil {
        tx.tx = types.NewContractCreation(tx.Nonce.Uint64(), tx.Value.BigInt(), tx.GasLimit.BigInt(), tx.GasPrice.BigInt(), data)
    } else {
        tx.tx = types.NewTransaction(tx.Nonce.Uint64(), *tx.To, tx.Value.BigInt(), tx.GasLimit.BigInt(), tx.GasPrice.BigInt(), data)
    }

    return nil
}

// SignTransactionResult represents a RLP encoded signed transaction.
type SignTransactionResult struct {
    Raw string `json:"raw"`
    Tx  *Tx    `json:"tx"`
}

func newTx(t *types.Transaction) *Tx {
    var signer types.Signer = types.HomesteadSigner{}
    if t.Protected() {
        signer = types.NewEIP155Signer(t.ChainId())
    }

    from, _ := types.Sender(signer, t)
    return &Tx{
        tx:       t,
        To:       t.To(),
        From:     from,
        Value:    rpc.NewHexNumber(t.Value()),
        Nonce:    rpc.NewHexNumber(t.Nonce()),
        Data:     "0x" + common.Bytes2Hex(t.Data()),
        GasLimit: rpc.NewHexNumber(t.Gas()),
        GasPrice: rpc.NewHexNumber(t.GasPrice()),
        Hash:     t.Hash(),
    }
}

// SignTransaction will sign the given transaction with the from account.
// The node needs to have the private key of the account corresponding with
// the given from address and it needs to be unlocked.
func (s *PublicTransactionPoolAPI) SignTransaction(ctx context.Context, args SignTransactionArgs) (*SignTransactionResult, error) {
    if args.Gas == nil {
        args.Gas = rpc.NewHexNumber(defaultGas)
    }
    if args.GasPrice == nil {
        price, err := s.b.SuggestPrice(ctx)
        if err != nil {
            return nil, err
        }
        args.GasPrice = rpc.NewHexNumber(price)
    }
    if args.Value == nil {
        args.Value = rpc.NewHexNumber(0)
    }

    if args.Nonce == nil {
        nonce, err := s.b.GetPoolNonce(ctx, args.From)
        if err != nil {
            return nil, err
        }
        args.Nonce = rpc.NewHexNumber(nonce)
    }

    var tx *types.Transaction
    if args.To == nil {
        tx = types.NewContractCreation(args.Nonce.Uint64(), args.Value.BigInt(), args.Gas.BigInt(), args.GasPrice.BigInt(), common.FromHex(args.Data))
    } else {
        tx = types.NewTransaction(args.Nonce.Uint64(), *args.To, args.Value.BigInt(), args.Gas.BigInt(), args.GasPrice.BigInt(), common.FromHex(args.Data))
    }

    signedTx, err := s.sign(args.From, tx)
    if err != nil {
        return nil, err
    }

    data, err := rlp.EncodeToBytes(signedTx)
    if err != nil {
        return nil, err
    }

    return &SignTransactionResult{"0x" + common.Bytes2Hex(data), newTx(signedTx)}, nil
}

// PendingTransactions returns the transactions that are in the transaction pool and have a from address that is one of
// the accounts this node manages.
func (s *PublicTransactionPoolAPI) PendingTransactions() ([]*RPCTransaction, error) {
    pending, err := s.b.GetPoolTransactions()
    if err != nil {
        return nil, err
    }

    transactions := make([]*RPCTransaction, 0, len(pending))
    for _, tx := range pending {
        var signer types.Signer = types.HomesteadSigner{}
        if tx.Protected() {
            signer = types.NewEIP155Signer(tx.ChainId())
        }
        from, _ := types.Sender(signer, tx)
        if s.b.AccountManager().HasAddress(from) {
            transactions = append(transactions, newRPCPendingTransaction(tx))
        }
    }
    return transactions, nil
}

// Resend accepts an existing transaction and a new gas price and limit. It will remove the given transaction from the
// pool and reinsert it with the new gas price and limit.
func (s *PublicTransactionPoolAPI) Resend(ctx context.Context, tx Tx, gasPrice, gasLimit *rpc.HexNumber) (common.Hash, error) {
    pending, err := s.b.GetPoolTransactions()
    if err != nil {
        return common.Hash{}, err
    }

    for _, p := range pending {
        var signer types.Signer = types.HomesteadSigner{}
        if p.Protected() {
            signer = types.NewEIP155Signer(p.ChainId())
        }

        if pFrom, err := types.Sender(signer, p); err == nil && pFrom == tx.From && signer.Hash(p) == signer.Hash(tx.tx) {
            if gasPrice == nil {
                gasPrice = rpc.NewHexNumber(tx.tx.GasPrice())
            }
            if gasLimit == nil {
                gasLimit = rpc.NewHexNumber(tx.tx.Gas())
            }

            var newTx *types.Transaction
            if tx.tx.To() == nil {
                newTx = types.NewContractCreation(tx.tx.Nonce(), tx.tx.Value(), gasLimit.BigInt(), gasPrice.BigInt(), tx.tx.Data())
            } else {
                newTx = types.NewTransaction(tx.tx.Nonce(), *tx.tx.To(), tx.tx.Value(), gasLimit.BigInt(), gasPrice.BigInt(), tx.tx.Data())
            }

            signedTx, err := s.sign(tx.From, newTx)
            if err != nil {
                return common.Hash{}, err
            }

            s.b.RemoveTx(tx.Hash)
            if err = s.b.SendTx(ctx, signedTx); err != nil {
                return common.Hash{}, err
            }

            return signedTx.Hash(), nil
        }
    }

    return common.Hash{}, fmt.Errorf("Transaction %#x not found", tx.Hash)
}

// PublicDebugAPI is the collection of Etheruem APIs exposed over the public
// debugging endpoint.
type PublicDebugAPI struct {
    b Backend
}

// NewPublicDebugAPI creates a new API definition for the public debug methods
// of the Ethereum service.
func NewPublicDebugAPI(b Backend) *PublicDebugAPI {
    return &PublicDebugAPI{b: b}
}

// GetBlockRlp retrieves the RLP encoded for of a single block.
func (api *PublicDebugAPI) GetBlockRlp(ctx context.Context, number uint64) (string, error) {
    block, _ := api.b.BlockByNumber(ctx, rpc.BlockNumber(number))
    if block == nil {
        return "", fmt.Errorf("block #%d not found", number)
    }
    encoded, err := rlp.EncodeToBytes(block)
    if err != nil {
        return "", err
    }
    return fmt.Sprintf("%x", encoded), nil
}

// PrintBlock retrieves a block and returns its pretty printed form.
func (api *PublicDebugAPI) PrintBlock(ctx context.Context, number uint64) (string, error) {
    block, _ := api.b.BlockByNumber(ctx, rpc.BlockNumber(number))
    if block == nil {
        return "", fmt.Errorf("block #%d not found", number)
    }
    return fmt.Sprintf("%s", block), nil
}

// SeedHash retrieves the seed hash of a block.
func (api *PublicDebugAPI) SeedHash(ctx context.Context, number uint64) (string, error) {
    block, _ := api.b.BlockByNumber(ctx, rpc.BlockNumber(number))
    if block == nil {
        return "", fmt.Errorf("block #%d not found", number)
    }
    hash, err := ethash.GetSeedHash(number)
    if err != nil {
        return "", err
    }
    return fmt.Sprintf("0x%x", hash), nil
}

// PrivateDebugAPI is the collection of Etheruem APIs exposed over the private
// debugging endpoint.
type PrivateDebugAPI struct {
    b Backend
}

// NewPrivateDebugAPI creates a new API definition for the private debug methods
// of the Ethereum service.
func NewPrivateDebugAPI(b Backend) *PrivateDebugAPI {
    return &PrivateDebugAPI{b: b}
}

// ChaindbProperty returns leveldb properties of the chain database.
func (api *PrivateDebugAPI) ChaindbProperty(property string) (string, error) {
    ldb, ok := api.b.ChainDb().(interface {
        LDB() *leveldb.DB
    })
    if !ok {
        return "", fmt.Errorf("chaindbProperty does not work for memory databases")
    }
    if property == "" {
        property = "leveldb.stats"
    } else if !strings.HasPrefix(property, "leveldb.") {
        property = "leveldb." + property
    }
    return ldb.LDB().GetProperty(property)
}

func (api *PrivateDebugAPI) ChaindbCompact() error {
    ldb, ok := api.b.ChainDb().(interface {
        LDB() *leveldb.DB
    })
    if !ok {
        return fmt.Errorf("chaindbCompact does not work for memory databases")
    }
    for b := byte(0); b < 255; b++ {
        glog.V(logger.Info).Infof("compacting chain DB range 0x%0.2X-0x%0.2X", b, b+1)
        err := ldb.LDB().CompactRange(util.Range{Start: []byte{b}, Limit: []byte{b + 1}})
        if err != nil {
            glog.Errorf("compaction error: %v", err)
            return err
        }
    }
    return nil
}

// SetHead rewinds the head of the blockchain to a previous block.
func (api *PrivateDebugAPI) SetHead(number rpc.HexNumber) {
    api.b.SetHead(uint64(number.Int64()))
}

// PublicNetAPI offers network related RPC methods
type PublicNetAPI struct {
    net            *p2p.Server
    networkVersion int
}

// NewPublicNetAPI creates a new net API instance.
func NewPublicNetAPI(net *p2p.Server, networkVersion int) *PublicNetAPI {
    return &PublicNetAPI{net, networkVersion}
}

// Listening returns an indication if the node is listening for network connections.
func (s *PublicNetAPI) Listening() bool {
    return true // always listening
}

// PeerCount returns the number of connected peers
func (s *PublicNetAPI) PeerCount() *rpc.HexNumber {
    return rpc.NewHexNumber(s.net.PeerCount())
}

// Version returns the current ethereum protocol version.
func (s *PublicNetAPI) Version() string {
    return fmt.Sprintf("%d", s.networkVersion)
}