les, light: implement ODR transaction lookup by hash (#19069)

* les, light: implement ODR transaction lookup by hash

* les: delete useless file

* internal/ethapi: always use backend to find transaction

* les, eth, internal/ethapi: renamed GetCanonicalTransaction to GetTransaction

* light: add canonical header verification to GetTransaction
This commit is contained in:
Felföldi Zsolt 2019-05-13 13:41:10 +02:00 committed by Péter Szilágyi
parent f4fb1a1801
commit 40cdcf8c47
16 changed files with 182 additions and 51 deletions

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@ -26,6 +26,7 @@ import (
"github.com/ethereum/go-ethereum/common/math"
"github.com/ethereum/go-ethereum/core"
"github.com/ethereum/go-ethereum/core/bloombits"
"github.com/ethereum/go-ethereum/core/rawdb"
"github.com/ethereum/go-ethereum/core/state"
"github.com/ethereum/go-ethereum/core/types"
"github.com/ethereum/go-ethereum/core/vm"
@ -178,6 +179,11 @@ func (b *EthAPIBackend) GetPoolTransaction(hash common.Hash) *types.Transaction
return b.eth.txPool.Get(hash)
}
func (b *EthAPIBackend) GetTransaction(ctx context.Context, txHash common.Hash) (*types.Transaction, common.Hash, uint64, uint64, error) {
tx, blockHash, blockNumber, index := rawdb.ReadTransaction(b.eth.ChainDb(), txHash)
return tx, blockHash, blockNumber, index, nil
}
func (b *EthAPIBackend) GetPoolNonce(ctx context.Context, addr common.Address) (uint64, error) {
return b.eth.txPool.State().GetNonce(addr), nil
}

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@ -1155,25 +1155,32 @@ func (s *PublicTransactionPoolAPI) GetTransactionCount(ctx context.Context, addr
}
// GetTransactionByHash returns the transaction for the given hash
func (s *PublicTransactionPoolAPI) GetTransactionByHash(ctx context.Context, hash common.Hash) *RPCTransaction {
func (s *PublicTransactionPoolAPI) GetTransactionByHash(ctx context.Context, hash common.Hash) (*RPCTransaction, error) {
// Try to return an already finalized transaction
if tx, blockHash, blockNumber, index := rawdb.ReadTransaction(s.b.ChainDb(), hash); tx != nil {
return newRPCTransaction(tx, blockHash, blockNumber, index)
tx, blockHash, blockNumber, index, err := s.b.GetTransaction(ctx, hash)
if err != nil {
return nil, err
}
if tx != nil {
return newRPCTransaction(tx, blockHash, blockNumber, index), nil
}
// No finalized transaction, try to retrieve it from the pool
if tx := s.b.GetPoolTransaction(hash); tx != nil {
return newRPCPendingTransaction(tx)
return newRPCPendingTransaction(tx), nil
}
// Transaction unknown, return as such
return nil
return nil, nil
}
// GetRawTransactionByHash returns the bytes of the transaction for the given hash.
func (s *PublicTransactionPoolAPI) GetRawTransactionByHash(ctx context.Context, hash common.Hash) (hexutil.Bytes, error) {
var tx *types.Transaction
// Retrieve a finalized transaction, or a pooled otherwise
if tx, _, _, _ = rawdb.ReadTransaction(s.b.ChainDb(), hash); tx == nil {
tx, _, _, _, err := s.b.GetTransaction(ctx, hash)
if err != nil {
return nil, err
}
if tx == nil {
if tx = s.b.GetPoolTransaction(hash); tx == nil {
// Transaction not found anywhere, abort
return nil, nil

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@ -62,6 +62,7 @@ type Backend interface {
// TxPool API
SendTx(ctx context.Context, signedTx *types.Transaction) error
GetTransaction(ctx context.Context, txHash common.Hash) (*types.Transaction, common.Hash, uint64, uint64, error)
GetPoolTransactions() (types.Transactions, error)
GetPoolTransaction(txHash common.Hash) *types.Transaction
GetPoolNonce(ctx context.Context, addr common.Address) (uint64, error)

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@ -132,6 +132,10 @@ func (b *LesApiBackend) GetPoolTransaction(txHash common.Hash) *types.Transactio
return b.eth.txPool.GetTransaction(txHash)
}
func (b *LesApiBackend) GetTransaction(ctx context.Context, txHash common.Hash) (*types.Transaction, common.Hash, uint64, uint64, error) {
return light.GetTransaction(ctx, b.eth.odr, txHash)
}
func (b *LesApiBackend) GetPoolNonce(ctx context.Context, addr common.Address) (uint64, error) {
return b.eth.txPool.GetNonce(ctx, addr)
}

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@ -114,9 +114,9 @@ func New(ctx *node.ServiceContext, config *eth.Config) (*LightEthereum, error) {
if leth.config.ULC != nil {
trustedNodes = leth.config.ULC.TrustedServers
}
leth.relay = NewLesTxRelay(peers, leth.reqDist)
leth.serverPool = newServerPool(chainDb, quitSync, &leth.wg, trustedNodes)
leth.retriever = newRetrieveManager(peers, leth.reqDist, leth.serverPool)
leth.relay = NewLesTxRelay(peers, leth.retriever)
leth.odr = NewLesOdr(chainDb, light.DefaultClientIndexerConfig, leth.retriever)
leth.chtIndexer = light.NewChtIndexer(chainDb, leth.odr, params.CHTFrequency, params.HelperTrieConfirmations)
@ -271,6 +271,7 @@ func (s *LightEthereum) Start(srvr *p2p.Server) error {
// Ethereum protocol.
func (s *LightEthereum) Stop() error {
s.odr.Stop()
s.relay.Stop()
s.bloomIndexer.Close()
s.chtIndexer.Close()
s.blockchain.Stop()

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@ -979,7 +979,7 @@ func (pm *ProtocolManager) handleMsg(p *peer) error {
return errResp(ErrRequestRejected, "")
}
go func() {
stats := make([]txStatus, len(req.Txs))
stats := make([]light.TxStatus, len(req.Txs))
for i, tx := range req.Txs {
if i != 0 && !task.waitOrStop() {
return
@ -1014,7 +1014,7 @@ func (pm *ProtocolManager) handleMsg(p *peer) error {
return errResp(ErrRequestRejected, "")
}
go func() {
stats := make([]txStatus, len(req.Hashes))
stats := make([]light.TxStatus, len(req.Hashes))
for i, hash := range req.Hashes {
if i != 0 && !task.waitOrStop() {
return
@ -1032,7 +1032,7 @@ func (pm *ProtocolManager) handleMsg(p *peer) error {
p.Log().Trace("Received tx status response")
var resp struct {
ReqID, BV uint64
Status []txStatus
Status []light.TxStatus
}
if err := msg.Decode(&resp); err != nil {
return errResp(ErrDecode, "msg %v: %v", msg, err)
@ -1040,6 +1040,13 @@ func (pm *ProtocolManager) handleMsg(p *peer) error {
p.fcServer.ReceivedReply(resp.ReqID, resp.BV)
p.Log().Trace("Received helper trie proof response")
deliverMsg = &Msg{
MsgType: MsgTxStatus,
ReqID: resp.ReqID,
Obj: resp.Status,
}
default:
p.Log().Trace("Received unknown message", "code", msg.Code)
return errResp(ErrInvalidMsgCode, "%v", msg.Code)
@ -1097,8 +1104,8 @@ func (pm *ProtocolManager) getHelperTrieAuxData(req HelperTrieReq) []byte {
return nil
}
func (pm *ProtocolManager) txStatus(hash common.Hash) txStatus {
var stat txStatus
func (pm *ProtocolManager) txStatus(hash common.Hash) light.TxStatus {
var stat light.TxStatus
stat.Status = pm.txpool.Status([]common.Hash{hash})[0]
// If the transaction is unknown to the pool, try looking it up locally
if stat.Status == core.TxStatusUnknown {

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@ -443,7 +443,7 @@ func TestTransactionStatusLes2(t *testing.T) {
var reqID uint64
test := func(tx *types.Transaction, send bool, expStatus txStatus) {
test := func(tx *types.Transaction, send bool, expStatus light.TxStatus) {
reqID++
if send {
cost := peer.GetRequestCost(SendTxV2Msg, 1)
@ -452,7 +452,7 @@ func TestTransactionStatusLes2(t *testing.T) {
cost := peer.GetRequestCost(GetTxStatusMsg, 1)
sendRequest(peer.app, GetTxStatusMsg, reqID, cost, []common.Hash{tx.Hash()})
}
if err := expectResponse(peer.app, TxStatusMsg, reqID, testBufLimit, []txStatus{expStatus}); err != nil {
if err := expectResponse(peer.app, TxStatusMsg, reqID, testBufLimit, []light.TxStatus{expStatus}); err != nil {
t.Errorf("transaction status mismatch")
}
}
@ -461,20 +461,20 @@ func TestTransactionStatusLes2(t *testing.T) {
// test error status by sending an underpriced transaction
tx0, _ := types.SignTx(types.NewTransaction(0, acc1Addr, big.NewInt(10000), params.TxGas, nil, nil), signer, testBankKey)
test(tx0, true, txStatus{Status: core.TxStatusUnknown, Error: core.ErrUnderpriced.Error()})
test(tx0, true, light.TxStatus{Status: core.TxStatusUnknown, Error: core.ErrUnderpriced.Error()})
tx1, _ := types.SignTx(types.NewTransaction(0, acc1Addr, big.NewInt(10000), params.TxGas, big.NewInt(100000000000), nil), signer, testBankKey)
test(tx1, false, txStatus{Status: core.TxStatusUnknown}) // query before sending, should be unknown
test(tx1, true, txStatus{Status: core.TxStatusPending}) // send valid processable tx, should return pending
test(tx1, true, txStatus{Status: core.TxStatusPending}) // adding it again should not return an error
test(tx1, false, light.TxStatus{Status: core.TxStatusUnknown}) // query before sending, should be unknown
test(tx1, true, light.TxStatus{Status: core.TxStatusPending}) // send valid processable tx, should return pending
test(tx1, true, light.TxStatus{Status: core.TxStatusPending}) // adding it again should not return an error
tx2, _ := types.SignTx(types.NewTransaction(1, acc1Addr, big.NewInt(10000), params.TxGas, big.NewInt(100000000000), nil), signer, testBankKey)
tx3, _ := types.SignTx(types.NewTransaction(2, acc1Addr, big.NewInt(10000), params.TxGas, big.NewInt(100000000000), nil), signer, testBankKey)
// send transactions in the wrong order, tx3 should be queued
test(tx3, true, txStatus{Status: core.TxStatusQueued})
test(tx2, true, txStatus{Status: core.TxStatusPending})
test(tx3, true, light.TxStatus{Status: core.TxStatusQueued})
test(tx2, true, light.TxStatus{Status: core.TxStatusPending})
// query again, now tx3 should be pending too
test(tx3, false, txStatus{Status: core.TxStatusPending})
test(tx3, false, light.TxStatus{Status: core.TxStatusPending})
// generate and add a block with tx1 and tx2 included
gchain, _ := core.GenerateChain(params.TestChainConfig, chain.GetBlockByNumber(0), ethash.NewFaker(), db, 1, func(i int, block *core.BlockGen) {
@ -497,8 +497,8 @@ func TestTransactionStatusLes2(t *testing.T) {
// check if their status is included now
block1hash := rawdb.ReadCanonicalHash(db, 1)
test(tx1, false, txStatus{Status: core.TxStatusIncluded, Lookup: &rawdb.LegacyTxLookupEntry{BlockHash: block1hash, BlockIndex: 1, Index: 0}})
test(tx2, false, txStatus{Status: core.TxStatusIncluded, Lookup: &rawdb.LegacyTxLookupEntry{BlockHash: block1hash, BlockIndex: 1, Index: 1}})
test(tx1, false, light.TxStatus{Status: core.TxStatusIncluded, Lookup: &rawdb.LegacyTxLookupEntry{BlockHash: block1hash, BlockIndex: 1, Index: 0}})
test(tx2, false, light.TxStatus{Status: core.TxStatusIncluded, Lookup: &rawdb.LegacyTxLookupEntry{BlockHash: block1hash, BlockIndex: 1, Index: 1}})
// create a reorg that rolls them back
gchain, _ = core.GenerateChain(params.TestChainConfig, chain.GetBlockByNumber(0), ethash.NewFaker(), db, 2, func(i int, block *core.BlockGen) {})
@ -516,6 +516,6 @@ func TestTransactionStatusLes2(t *testing.T) {
t.Fatalf("pending count mismatch: have %d, want 3", pending)
}
// check if their status is pending again
test(tx1, false, txStatus{Status: core.TxStatusPending})
test(tx2, false, txStatus{Status: core.TxStatusPending})
test(tx1, false, light.TxStatus{Status: core.TxStatusPending})
test(tx2, false, light.TxStatus{Status: core.TxStatusPending})
}

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@ -148,6 +148,7 @@ func newTestProtocolManager(lightSync bool, blocks int, generator func(int, *cor
}
genesis = gspec.MustCommit(db)
chain BlockChain
pool txPool
)
if peers == nil {
peers = newPeerSet()
@ -162,13 +163,14 @@ func newTestProtocolManager(lightSync bool, blocks int, generator func(int, *cor
panic(err)
}
chain = blockchain
pool = core.NewTxPool(core.DefaultTxPoolConfig, gspec.Config, blockchain)
}
indexConfig := light.TestServerIndexerConfig
if lightSync {
indexConfig = light.TestClientIndexerConfig
}
pm, err := NewProtocolManager(gspec.Config, indexConfig, lightSync, NetworkId, evmux, engine, peers, chain, nil, db, odr, nil, nil, make(chan struct{}), new(sync.WaitGroup), ulcConfig)
pm, err := NewProtocolManager(gspec.Config, indexConfig, lightSync, NetworkId, evmux, engine, peers, chain, pool, db, odr, nil, nil, make(chan struct{}), new(sync.WaitGroup), ulcConfig)
if err != nil {
return nil, err
}

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@ -86,6 +86,7 @@ const (
MsgReceipts
MsgProofsV2
MsgHelperTrieProofs
MsgTxStatus
)
// Msg encodes a LES message that delivers reply data for a request

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@ -66,6 +66,8 @@ func LesRequest(req light.OdrRequest) LesOdrRequest {
return (*ChtRequest)(r)
case *light.BloomRequest:
return (*BloomRequest)(r)
case *light.TxStatusRequest:
return (*TxStatusRequest)(r)
default:
return nil
}
@ -471,6 +473,44 @@ func (r *BloomRequest) Validate(db ethdb.Database, msg *Msg) error {
return nil
}
// TxStatusRequest is the ODR request type for transaction status
type TxStatusRequest light.TxStatusRequest
// GetCost returns the cost of the given ODR request according to the serving
// peer's cost table (implementation of LesOdrRequest)
func (r *TxStatusRequest) GetCost(peer *peer) uint64 {
return peer.GetRequestCost(GetTxStatusMsg, len(r.Hashes))
}
// CanSend tells if a certain peer is suitable for serving the given request
func (r *TxStatusRequest) CanSend(peer *peer) bool {
return peer.version >= lpv2
}
// Request sends an ODR request to the LES network (implementation of LesOdrRequest)
func (r *TxStatusRequest) Request(reqID uint64, peer *peer) error {
peer.Log().Debug("Requesting transaction status", "count", len(r.Hashes))
return peer.RequestTxStatus(reqID, r.GetCost(peer), r.Hashes)
}
// Valid processes an ODR request reply message from the LES network
// returns true and stores results in memory if the message was a valid reply
// to the request (implementation of LesOdrRequest)
func (r *TxStatusRequest) Validate(db ethdb.Database, msg *Msg) error {
log.Debug("Validating transaction status", "count", len(r.Hashes))
// Ensure we have a correct message with a single block body
if msg.MsgType != MsgTxStatus {
return errInvalidMessageType
}
status := msg.Obj.([]light.TxStatus)
if len(status) != len(r.Hashes) {
return errInvalidEntryCount
}
r.Status = status
return nil
}
// readTraceDB stores the keys of database reads. We use this to check that received node
// sets contain only the trie nodes necessary to make proofs pass.
type readTraceDB struct {

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@ -38,7 +38,7 @@ import (
type odrTestFn func(ctx context.Context, db ethdb.Database, config *params.ChainConfig, bc *core.BlockChain, lc *light.LightChain, bhash common.Hash) []byte
func TestOdrGetBlockLes2(t *testing.T) { testOdr(t, 2, 1, odrGetBlock) }
func TestOdrGetBlockLes2(t *testing.T) { testOdr(t, 2, 1, true, odrGetBlock) }
func odrGetBlock(ctx context.Context, db ethdb.Database, config *params.ChainConfig, bc *core.BlockChain, lc *light.LightChain, bhash common.Hash) []byte {
var block *types.Block
@ -54,7 +54,7 @@ func odrGetBlock(ctx context.Context, db ethdb.Database, config *params.ChainCon
return rlp
}
func TestOdrGetReceiptsLes2(t *testing.T) { testOdr(t, 2, 1, odrGetReceipts) }
func TestOdrGetReceiptsLes2(t *testing.T) { testOdr(t, 2, 1, true, odrGetReceipts) }
func odrGetReceipts(ctx context.Context, db ethdb.Database, config *params.ChainConfig, bc *core.BlockChain, lc *light.LightChain, bhash common.Hash) []byte {
var receipts types.Receipts
@ -74,7 +74,7 @@ func odrGetReceipts(ctx context.Context, db ethdb.Database, config *params.Chain
return rlp
}
func TestOdrAccountsLes2(t *testing.T) { testOdr(t, 2, 1, odrAccounts) }
func TestOdrAccountsLes2(t *testing.T) { testOdr(t, 2, 1, true, odrAccounts) }
func odrAccounts(ctx context.Context, db ethdb.Database, config *params.ChainConfig, bc *core.BlockChain, lc *light.LightChain, bhash common.Hash) []byte {
dummyAddr := common.HexToAddress("1234567812345678123456781234567812345678")
@ -102,7 +102,7 @@ func odrAccounts(ctx context.Context, db ethdb.Database, config *params.ChainCon
return res
}
func TestOdrContractCallLes2(t *testing.T) { testOdr(t, 2, 2, odrContractCall) }
func TestOdrContractCallLes2(t *testing.T) { testOdr(t, 2, 2, true, odrContractCall) }
type callmsg struct {
types.Message
@ -151,8 +151,32 @@ func odrContractCall(ctx context.Context, db ethdb.Database, config *params.Chai
return res
}
func TestOdrTxStatusLes2(t *testing.T) { testOdr(t, 2, 1, false, odrTxStatus) }
func odrTxStatus(ctx context.Context, db ethdb.Database, config *params.ChainConfig, bc *core.BlockChain, lc *light.LightChain, bhash common.Hash) []byte {
var txs types.Transactions
if bc != nil {
block := bc.GetBlockByHash(bhash)
txs = block.Transactions()
} else {
if block, _ := lc.GetBlockByHash(ctx, bhash); block != nil {
btxs := block.Transactions()
txs = make(types.Transactions, len(btxs))
for i, tx := range btxs {
var err error
txs[i], _, _, _, err = light.GetTransaction(ctx, lc.Odr(), tx.Hash())
if err != nil {
return nil
}
}
}
}
rlp, _ := rlp.EncodeToBytes(txs)
return rlp
}
// testOdr tests odr requests whose validation guaranteed by block headers.
func testOdr(t *testing.T, protocol int, expFail uint64, fn odrTestFn) {
func testOdr(t *testing.T, protocol int, expFail uint64, checkCached bool, fn odrTestFn) {
// Assemble the test environment
server, client, tearDown := newClientServerEnv(t, 4, protocol, nil, true)
defer tearDown()
@ -193,9 +217,10 @@ func testOdr(t *testing.T, protocol int, expFail uint64, fn odrTestFn) {
client.rPeer.hasBlock = func(common.Hash, uint64, bool) bool { return true }
client.peers.lock.Unlock()
test(5)
// still expect all retrievals to pass, now data should be cached locally
client.peers.Unregister(client.rPeer.id)
time.Sleep(time.Millisecond * 10) // ensure that all peerSetNotify callbacks are executed
test(5)
if checkCached {
// still expect all retrievals to pass, now data should be cached locally
client.peers.Unregister(client.rPeer.id)
time.Sleep(time.Millisecond * 10) // ensure that all peerSetNotify callbacks are executed
test(5)
}
}

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@ -317,7 +317,7 @@ func (p *peer) ReplyHelperTrieProofs(reqID uint64, resp HelperTrieResps) *reply
}
// ReplyTxStatus creates a reply with a batch of transaction status records, corresponding to the ones requested.
func (p *peer) ReplyTxStatus(reqID uint64, stats []txStatus) *reply {
func (p *peer) ReplyTxStatus(reqID uint64, stats []light.TxStatus) *reply {
data, _ := rlp.EncodeToBytes(stats)
return &reply{p.rw, TxStatusMsg, reqID, data}
}

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@ -24,8 +24,6 @@ import (
"math/big"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/core"
"github.com/ethereum/go-ethereum/core/rawdb"
"github.com/ethereum/go-ethereum/crypto"
"github.com/ethereum/go-ethereum/p2p/enode"
"github.com/ethereum/go-ethereum/rlp"
@ -227,9 +225,3 @@ type CodeData []struct {
}
type proofsData [][]rlp.RawValue
type txStatus struct {
Status core.TxStatus
Lookup *rawdb.LegacyTxLookupEntry `rlp:"nil"`
Error string
}

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@ -17,6 +17,7 @@
package les
import (
"context"
"sync"
"github.com/ethereum/go-ethereum/common"
@ -36,21 +37,27 @@ type LesTxRelay struct {
peerList []*peer
peerStartPos int
lock sync.RWMutex
stop chan struct{}
reqDist *requestDistributor
retriever *retrieveManager
}
func NewLesTxRelay(ps *peerSet, reqDist *requestDistributor) *LesTxRelay {
func NewLesTxRelay(ps *peerSet, retriever *retrieveManager) *LesTxRelay {
r := &LesTxRelay{
txSent: make(map[common.Hash]*ltrInfo),
txPending: make(map[common.Hash]struct{}),
ps: ps,
reqDist: reqDist,
retriever: retriever,
stop: make(chan struct{}),
}
ps.notify(r)
return r
}
func (self *LesTxRelay) Stop() {
close(self.stop)
}
func (self *LesTxRelay) registerPeer(p *peer) {
self.lock.Lock()
defer self.lock.Unlock()
@ -132,7 +139,7 @@ func (self *LesTxRelay) send(txs types.Transactions, count int) {
return func() { peer.SendTxs(reqID, cost, enc) }
},
}
self.reqDist.queue(rq)
go self.retriever.retrieve(context.Background(), reqID, rq, func(p distPeer, msg *Msg) error { return nil }, self.stop)
}
}

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@ -175,3 +175,20 @@ func (req *BloomRequest) StoreResult(db ethdb.Database) {
rawdb.WriteBloomBits(db, req.BitIdx, sectionIdx, sectionHead, req.BloomBits[i])
}
}
// TxStatus describes the status of a transaction
type TxStatus struct {
Status core.TxStatus
Lookup *rawdb.LegacyTxLookupEntry `rlp:"nil"`
Error string
}
// TxStatusRequest is the ODR request type for retrieving transaction status
type TxStatusRequest struct {
OdrRequest
Hashes []common.Hash
Status []TxStatus
}
// StoreResult stores the retrieved data in local database
func (req *TxStatusRequest) StoreResult(db ethdb.Database) {}

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@ -21,6 +21,7 @@ import (
"context"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/core"
"github.com/ethereum/go-ethereum/core/rawdb"
"github.com/ethereum/go-ethereum/core/types"
"github.com/ethereum/go-ethereum/crypto"
@ -227,3 +228,23 @@ func GetBloomBits(ctx context.Context, odr OdrBackend, bitIdx uint, sectionIdxLi
return result, nil
}
}
// GetTransaction retrieves a canonical transaction by hash and also returns its position in the chain
func GetTransaction(ctx context.Context, odr OdrBackend, txHash common.Hash) (*types.Transaction, common.Hash, uint64, uint64, error) {
r := &TxStatusRequest{Hashes: []common.Hash{txHash}}
if err := odr.Retrieve(ctx, r); err != nil || r.Status[0].Status != core.TxStatusIncluded {
return nil, common.Hash{}, 0, 0, err
} else {
pos := r.Status[0].Lookup
// first ensure that we have the header, otherwise block body retrieval will fail
// also verify if this is a canonical block by getting the header by number and checking its hash
if header, err := GetHeaderByNumber(ctx, odr, pos.BlockIndex); err != nil || header.Hash() != pos.BlockHash {
return nil, common.Hash{}, 0, 0, err
}
if body, err := GetBody(ctx, odr, pos.BlockHash, pos.BlockIndex); err != nil || uint64(len(body.Transactions)) <= pos.Index || body.Transactions[pos.Index].Hash() != txHash {
return nil, common.Hash{}, 0, 0, err
} else {
return body.Transactions[pos.Index], pos.BlockHash, pos.BlockIndex, pos.Index, nil
}
}
}