plugeth/ethclient/ethclient.go
Felix Lange 3bc0fe1ee3 ethclient, ethereum: add NotFound, split transactions out of ChainReader
ethclient now returns ethereum.NotFound if the server returns null and
no error while accessing blockchain data.

The light client cannot provide arbitrary transactions. The change to
split transaction access into its own interface emphasizes that
transactions should not be relied on and recommends use of logs.
2016-12-05 10:57:11 +01:00

443 lines
16 KiB
Go

// 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/>.
// Package ethclient provides a client for the Ethereum RPC API.
package ethclient
import (
"encoding/json"
"fmt"
"math/big"
"github.com/ethereum/go-ethereum"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/common/hexutil"
"github.com/ethereum/go-ethereum/core/types"
"github.com/ethereum/go-ethereum/core/vm"
"github.com/ethereum/go-ethereum/rlp"
"github.com/ethereum/go-ethereum/rpc"
"golang.org/x/net/context"
)
// Client defines typed wrappers for the Ethereum RPC API.
type Client struct {
c *rpc.Client
}
// Dial connects a client to the given URL.
func Dial(rawurl string) (*Client, error) {
c, err := rpc.Dial(rawurl)
if err != nil {
return nil, err
}
return NewClient(c), nil
}
// NewClient creates a client that uses the given RPC client.
func NewClient(c *rpc.Client) *Client {
return &Client{c}
}
// Blockchain Access
// BlockByHash returns the given full block.
//
// Note that loading full blocks requires two requests. Use HeaderByHash
// if you don't need all transactions or uncle headers.
func (ec *Client) BlockByHash(ctx context.Context, hash common.Hash) (*types.Block, error) {
return ec.getBlock(ctx, "eth_getBlockByHash", hash, true)
}
// BlockByNumber returns a block from the current canonical chain. If number is nil, the
// latest known block is returned.
//
// Note that loading full blocks requires two requests. Use HeaderByNumber
// if you don't need all transactions or uncle headers.
func (ec *Client) BlockByNumber(ctx context.Context, number *big.Int) (*types.Block, error) {
return ec.getBlock(ctx, "eth_getBlockByNumber", toBlockNumArg(number), true)
}
type rpcBlock struct {
Hash common.Hash `json:"hash"`
Transactions []*types.Transaction `json:"transactions"`
UncleHashes []common.Hash `json:"uncles"`
}
func (ec *Client) getBlock(ctx context.Context, method string, args ...interface{}) (*types.Block, error) {
var raw json.RawMessage
err := ec.c.CallContext(ctx, &raw, method, args...)
if err != nil {
return nil, err
} else if len(raw) == 0 {
return nil, ethereum.NotFound
}
// Decode header and transactions.
var head *types.Header
var body rpcBlock
if err := json.Unmarshal(raw, &head); err != nil {
return nil, err
}
if err := json.Unmarshal(raw, &body); err != nil {
return nil, err
}
// Quick-verify transaction and uncle lists. This mostly helps with debugging the server.
if head.UncleHash == types.EmptyUncleHash && len(body.UncleHashes) > 0 {
return nil, fmt.Errorf("server returned non-empty uncle list but block header indicates no uncles")
}
if head.UncleHash != types.EmptyUncleHash && len(body.UncleHashes) == 0 {
return nil, fmt.Errorf("server returned empty uncle list but block header indicates uncles")
}
if head.TxHash == types.EmptyRootHash && len(body.Transactions) > 0 {
return nil, fmt.Errorf("server returned non-empty transaction list but block header indicates no transactions")
}
if head.TxHash != types.EmptyRootHash && len(body.Transactions) == 0 {
return nil, fmt.Errorf("server returned empty transaction list but block header indicates transactions")
}
// Load uncles because they are not included in the block response.
var uncles []*types.Header
if len(body.UncleHashes) > 0 {
uncles = make([]*types.Header, len(body.UncleHashes))
reqs := make([]rpc.BatchElem, len(body.UncleHashes))
for i := range reqs {
reqs[i] = rpc.BatchElem{
Method: "eth_getUncleByBlockHashAndIndex",
Args: []interface{}{body.Hash, hexutil.EncodeUint64(uint64(i))},
Result: &uncles[i],
}
}
if err := ec.c.BatchCallContext(ctx, reqs); err != nil {
return nil, err
}
for i := range reqs {
if reqs[i].Error != nil {
return nil, reqs[i].Error
}
if uncles[i] == nil {
return nil, fmt.Errorf("got null header for uncle %d of block %x", i, body.Hash[:])
}
}
}
return types.NewBlockWithHeader(head).WithBody(body.Transactions, uncles), nil
}
// HeaderByHash returns the block header with the given hash.
func (ec *Client) HeaderByHash(ctx context.Context, hash common.Hash) (*types.Header, error) {
var head *types.Header
err := ec.c.CallContext(ctx, &head, "eth_getBlockByHash", hash, false)
if err == nil && head == nil {
err = ethereum.NotFound
}
return head, err
}
// HeaderByNumber returns a block header from the current canonical chain. If number is
// nil, the latest known header is returned.
func (ec *Client) HeaderByNumber(ctx context.Context, number *big.Int) (*types.Header, error) {
var head *types.Header
err := ec.c.CallContext(ctx, &head, "eth_getBlockByNumber", toBlockNumArg(number), false)
if err == nil && head == nil {
err = ethereum.NotFound
}
return head, err
}
// TransactionByHash returns the transaction with the given hash.
func (ec *Client) TransactionByHash(ctx context.Context, hash common.Hash) (tx *types.Transaction, isPending bool, err error) {
var raw json.RawMessage
err = ec.c.CallContext(ctx, &raw, "eth_getTransactionByHash", hash)
if err != nil {
return nil, false, err
} else if len(raw) == 0 {
return nil, false, ethereum.NotFound
}
if err := json.Unmarshal(raw, tx); err != nil {
return nil, false, err
} else if _, r, _ := tx.RawSignatureValues(); r == nil {
return nil, false, fmt.Errorf("server returned transaction without signature")
}
var block struct{ BlockHash *common.Hash }
if err := json.Unmarshal(raw, &block); err != nil {
return nil, false, err
}
return tx, block.BlockHash == nil, nil
}
// TransactionCount returns the total number of transactions in the given block.
func (ec *Client) TransactionCount(ctx context.Context, blockHash common.Hash) (uint, error) {
var num hexutil.Uint
err := ec.c.CallContext(ctx, &num, "eth_getBlockTransactionCountByHash", blockHash)
return uint(num), err
}
// TransactionInBlock returns a single transaction at index in the given block.
func (ec *Client) TransactionInBlock(ctx context.Context, blockHash common.Hash, index uint) (*types.Transaction, error) {
var tx *types.Transaction
err := ec.c.CallContext(ctx, &tx, "eth_getTransactionByBlockHashAndIndex", blockHash, index)
if err == nil {
if tx == nil {
return nil, ethereum.NotFound
} else if _, r, _ := tx.RawSignatureValues(); r == nil {
return nil, fmt.Errorf("server returned transaction without signature")
}
}
return tx, err
}
// TransactionReceipt returns the receipt of a transaction by transaction hash.
// Note that the receipt is not available for pending transactions.
func (ec *Client) TransactionReceipt(ctx context.Context, txHash common.Hash) (*types.Receipt, error) {
var r *types.Receipt
err := ec.c.CallContext(ctx, &r, "eth_getTransactionReceipt", txHash)
if err == nil {
if r == nil {
return nil, ethereum.NotFound
} else if len(r.PostState) == 0 {
return nil, fmt.Errorf("server returned receipt without post state")
}
}
return r, err
}
func toBlockNumArg(number *big.Int) string {
if number == nil {
return "latest"
}
return hexutil.EncodeBig(number)
}
type rpcProgress struct {
StartingBlock hexutil.Uint64
CurrentBlock hexutil.Uint64
HighestBlock hexutil.Uint64
PulledStates hexutil.Uint64
KnownStates hexutil.Uint64
}
// SyncProgress retrieves the current progress of the sync algorithm. If there's
// no sync currently running, it returns nil.
func (ec *Client) SyncProgress(ctx context.Context) (*ethereum.SyncProgress, error) {
var raw json.RawMessage
if err := ec.c.CallContext(ctx, &raw, "eth_syncing"); err != nil {
return nil, err
}
// Handle the possible response types
var syncing bool
if err := json.Unmarshal(raw, &syncing); err == nil {
return nil, nil // Not syncing (always false)
}
var progress *rpcProgress
if err := json.Unmarshal(raw, &progress); err != nil {
return nil, err
}
return &ethereum.SyncProgress{
StartingBlock: uint64(progress.StartingBlock),
CurrentBlock: uint64(progress.CurrentBlock),
HighestBlock: uint64(progress.HighestBlock),
PulledStates: uint64(progress.PulledStates),
KnownStates: uint64(progress.KnownStates),
}, nil
}
// SubscribeNewHead subscribes to notifications about the current blockchain head
// on the given channel.
func (ec *Client) SubscribeNewHead(ctx context.Context, ch chan<- *types.Header) (ethereum.Subscription, error) {
return ec.c.EthSubscribe(ctx, ch, "newHeads", map[string]struct{}{})
}
// State Access
// BalanceAt returns the wei balance of the given account.
// The block number can be nil, in which case the balance is taken from the latest known block.
func (ec *Client) BalanceAt(ctx context.Context, account common.Address, blockNumber *big.Int) (*big.Int, error) {
var result hexutil.Big
err := ec.c.CallContext(ctx, &result, "eth_getBalance", account, toBlockNumArg(blockNumber))
return (*big.Int)(&result), err
}
// StorageAt returns the value of key in the contract storage of the given account.
// The block number can be nil, in which case the value is taken from the latest known block.
func (ec *Client) StorageAt(ctx context.Context, account common.Address, key common.Hash, blockNumber *big.Int) ([]byte, error) {
var result hexutil.Bytes
err := ec.c.CallContext(ctx, &result, "eth_getStorageAt", account, key, toBlockNumArg(blockNumber))
return result, err
}
// CodeAt returns the contract code of the given account.
// The block number can be nil, in which case the code is taken from the latest known block.
func (ec *Client) CodeAt(ctx context.Context, account common.Address, blockNumber *big.Int) ([]byte, error) {
var result hexutil.Bytes
err := ec.c.CallContext(ctx, &result, "eth_getCode", account, toBlockNumArg(blockNumber))
return result, err
}
// NonceAt returns the account nonce of the given account.
// The block number can be nil, in which case the nonce is taken from the latest known block.
func (ec *Client) NonceAt(ctx context.Context, account common.Address, blockNumber *big.Int) (uint64, error) {
var result hexutil.Uint64
err := ec.c.CallContext(ctx, &result, "eth_getTransactionCount", account, toBlockNumArg(blockNumber))
return uint64(result), err
}
// Filters
// FilterLogs executes a filter query.
func (ec *Client) FilterLogs(ctx context.Context, q ethereum.FilterQuery) ([]vm.Log, error) {
var result []vm.Log
err := ec.c.CallContext(ctx, &result, "eth_getLogs", toFilterArg(q))
return result, err
}
// SubscribeFilterLogs subscribes to the results of a streaming filter query.
func (ec *Client) SubscribeFilterLogs(ctx context.Context, q ethereum.FilterQuery, ch chan<- vm.Log) (ethereum.Subscription, error) {
return ec.c.EthSubscribe(ctx, ch, "logs", toFilterArg(q))
}
func toFilterArg(q ethereum.FilterQuery) interface{} {
arg := map[string]interface{}{
"fromBlock": toBlockNumArg(q.FromBlock),
"toBlock": toBlockNumArg(q.ToBlock),
"address": q.Addresses,
"topics": q.Topics,
}
if q.FromBlock == nil {
arg["fromBlock"] = "0x0"
}
return arg
}
// Pending State
// PendingBalanceAt returns the wei balance of the given account in the pending state.
func (ec *Client) PendingBalanceAt(ctx context.Context, account common.Address) (*big.Int, error) {
var result hexutil.Big
err := ec.c.CallContext(ctx, &result, "eth_getBalance", account, "pending")
return (*big.Int)(&result), err
}
// PendingStorageAt returns the value of key in the contract storage of the given account in the pending state.
func (ec *Client) PendingStorageAt(ctx context.Context, account common.Address, key common.Hash) ([]byte, error) {
var result hexutil.Bytes
err := ec.c.CallContext(ctx, &result, "eth_getStorageAt", account, key, "pending")
return result, err
}
// PendingCodeAt returns the contract code of the given account in the pending state.
func (ec *Client) PendingCodeAt(ctx context.Context, account common.Address) ([]byte, error) {
var result hexutil.Bytes
err := ec.c.CallContext(ctx, &result, "eth_getCode", account, "pending")
return result, err
}
// PendingNonceAt 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 *Client) PendingNonceAt(ctx context.Context, account common.Address) (uint64, error) {
var result hexutil.Uint64
err := ec.c.CallContext(ctx, &result, "eth_getTransactionCount", account, "pending")
return uint64(result), err
}
// PendingTransactionCount returns the total number of transactions in the pending state.
func (ec *Client) PendingTransactionCount(ctx context.Context) (uint, error) {
var num hexutil.Uint
err := ec.c.CallContext(ctx, &num, "eth_getBlockTransactionCountByNumber", "pending")
return uint(num), err
}
// TODO: SubscribePendingTransactions (needs server side)
// 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 nil, 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 *Client) CallContract(ctx context.Context, msg ethereum.CallMsg, blockNumber *big.Int) ([]byte, error) {
var hex hexutil.Bytes
err := ec.c.CallContext(ctx, &hex, "eth_call", toCallArg(msg), toBlockNumArg(blockNumber))
if err != nil {
return nil, err
}
return hex, nil
}
// PendingCallContract executes a message call transaction using the EVM.
// The state seen by the contract call is the pending state.
func (ec *Client) PendingCallContract(ctx context.Context, msg ethereum.CallMsg) ([]byte, error) {
var hex hexutil.Bytes
err := ec.c.CallContext(ctx, &hex, "eth_call", toCallArg(msg), "pending")
if err != nil {
return nil, err
}
return hex, nil
}
// SuggestGasPrice retrieves the currently suggested gas price to allow a timely
// execution of a transaction.
func (ec *Client) SuggestGasPrice(ctx context.Context) (*big.Int, error) {
var hex hexutil.Big
if err := ec.c.CallContext(ctx, &hex, "eth_gasPrice"); err != nil {
return nil, err
}
return (*big.Int)(&hex), nil
}
// 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 *Client) EstimateGas(ctx context.Context, msg ethereum.CallMsg) (*big.Int, error) {
var hex hexutil.Big
err := ec.c.CallContext(ctx, &hex, "eth_estimateGas", toCallArg(msg))
if err != nil {
return nil, err
}
return (*big.Int)(&hex), nil
}
// 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 *Client) SendTransaction(ctx context.Context, tx *types.Transaction) error {
data, err := rlp.EncodeToBytes(tx)
if err != nil {
return err
}
return ec.c.CallContext(ctx, nil, "eth_sendRawTransaction", common.ToHex(data))
}
func toCallArg(msg ethereum.CallMsg) interface{} {
arg := map[string]interface{}{
"from": msg.From,
"to": msg.To,
}
if len(msg.Data) > 0 {
arg["data"] = hexutil.Bytes(msg.Data)
}
if msg.Value != nil {
arg["value"] = (*hexutil.Big)(msg.Value)
}
if msg.Gas != nil {
arg["gas"] = (*hexutil.Big)(msg.Gas)
}
if msg.GasPrice != nil {
arg["gasPrice"] = (*hexutil.Big)(msg.GasPrice)
}
return arg
}