nimbus-eth1/nimbus/rpc/p2p.nim

# Nimbus
# Copyright (c) 2018-2024 Status Research & Development GmbH
# Licensed under either of
#  * Apache License, version 2.0, ([LICENSE-APACHE](LICENSE-APACHE))
#  * MIT license ([LICENSE-MIT](LICENSE-MIT))
# at your option.
# This file may not be copied, modified, or distributed except according to
# those terms.

{.push raises: [].}

import
  std/[sequtils, times, tables, typetraits],
  json_rpc/rpcserver,
  stint,
  stew/byteutils,
  json_serialization,
  web3/conversions,
  json_serialization/stew/results,
  eth/common/eth_types_json_serialization,
  eth/[rlp, p2p],
  ".."/[transaction, evm/state, constants],
  ../db/ledger,
  ./rpc_types, ./rpc_utils, ./oracle,
  ../transaction/call_evm,
  ../core/tx_pool,
  ../core/eip4844,
  ../common/[common, context],
  ../utils/utils,
  ../beacon/web3_eth_conv,
  ../evm/evm_errors,
  ./filters

type
  Header = eth_types.Header
  Hash32 = eth_types.Hash32

proc getProof*(
    accDB: LedgerRef,
    address: eth_types.Address,
    slots: seq[UInt256]): ProofResponse =
  let
    acc = accDB.getEthAccount(address)
    accExists = accDB.accountExists(address)
    accountProof = accDB.getAccountProof(address)
    slotProofs = accDB.getStorageProof(address, slots)

  var storage = newSeqOfCap[StorageProof](slots.len)

  for i, slotKey in slots:
    let slotValue = accDB.getStorage(address, slotKey)
    storage.add(StorageProof(
        key: slotKey,
        value: slotValue,
        proof: seq[RlpEncodedBytes](slotProofs[i])))

  if accExists:
    ProofResponse(
          address: address,
          accountProof: seq[RlpEncodedBytes](accountProof),
          balance: acc.balance,
          nonce: w3Qty(acc.nonce),
          codeHash: acc.codeHash,
          storageHash: acc.storageRoot,
          storageProof: storage)
  else:
    ProofResponse(
          address: address,
          accountProof: seq[RlpEncodedBytes](accountProof),
          storageProof: storage)

proc setupEthRpc*(
    node: EthereumNode, ctx: EthContext, com: CommonRef,
    txPool: TxPoolRef, oracle: Oracle, server: RpcServer) =

  let chainDB = com.db
  proc getStateDB(header:Header): LedgerRef =
    ## Retrieves the account db from canonical head
    # we don't use accounst_cache here because it's only read operations
    LedgerRef.init(chainDB)

  proc stateDBFromTag(quantityTag: BlockTag, readOnly = true): LedgerRef
      {.gcsafe, raises: [CatchableError].} =
    getStateDB(chainDB.headerFromTag(quantityTag))

  server.rpc("eth_chainId") do() -> Web3Quantity:
    return w3Qty(distinctBase(com.chainId))

  server.rpc("eth_syncing") do() -> SyncingStatus:
    ## Returns SyncObject or false when not syncing.
    if com.syncState != Waiting:
      let sync = SyncObject(
        startingBlock: w3Qty com.syncStart,
        currentBlock : w3Qty com.syncCurrent,
        highestBlock : w3Qty com.syncHighest
      )
      return SyncingStatus(syncing: true, syncObject: sync)
    else:
      return SyncingStatus(syncing: false)

  server.rpc("eth_gasPrice") do() -> Web3Quantity:
    ## Returns an integer of the current gas price in wei.
    w3Qty(calculateMedianGasPrice(chainDB).uint64)

  server.rpc("eth_accounts") do() -> seq[eth_types.Address]:
    ## Returns a list of addresses owned by client.
    result = newSeqOfCap[eth_types.Address](ctx.am.numAccounts)
    for k in ctx.am.addresses:
      result.add k

  server.rpc("eth_blockNumber") do() -> Web3Quantity:
    ## Returns integer of the current block number the client is on.
    w3Qty(chainDB.getCanonicalHead().number)

  server.rpc("eth_getBalance") do(data: eth_types.Address, quantityTag: BlockTag) -> UInt256:
    ## Returns the balance of the account of given address.
    ##
    ## data: address to check for balance.
    ## quantityTag: integer block number, or the string "latest", "earliest" or "pending", see the default block parameter.
    ## Returns integer of the current balance in wei.
    let
      accDB   = stateDBFromTag(quantityTag)
      address = data
    accDB.getBalance(address)

  server.rpc("eth_getStorageAt") do(data: eth_types.Address, slot: UInt256, quantityTag: BlockTag) -> eth_types.FixedBytes[32]:
    ## Returns the value from a storage position at a given address.
    ##
    ## data: address of the storage.
    ## slot: integer of the position in the storage.
    ## quantityTag: integer block number, or the string "latest", "earliest" or "pending", see the default block parameter.
    ## Returns: the value at this storage position.
    let
      accDB   = stateDBFromTag(quantityTag)
      address = data
      data = accDB.getStorage(address, slot)
    data.to(Bytes32)

  server.rpc("eth_getTransactionCount") do(data: eth_types.Address, quantityTag: BlockTag) -> Web3Quantity:
    ## Returns the number of transactions sent from an address.
    ##
    ## data: address.
    ## quantityTag: integer block number, or the string "latest", "earliest" or "pending", see the default block parameter.
    ## Returns integer of the number of transactions send from this address.
    let
      address = data
      accDB   = stateDBFromTag(quantityTag)
    w3Qty(accDB.getNonce(address))

  server.rpc("eth_getBlockTransactionCountByHash") do(data: Hash32) -> Web3Quantity:
    ## Returns the number of transactions in a block from a block matching the given block hash.
    ##
    ## data: hash of a block
    ## Returns integer of the number of transactions in this block.
    let
      blockHash = data
      header    = chainDB.getBlockHeader(blockHash)
      txCount   = chainDB.getTransactionCount(header.txRoot)
    Web3Quantity(txCount)

  server.rpc("eth_getBlockTransactionCountByNumber") do(quantityTag: BlockTag) -> Web3Quantity:
    ## Returns the number of transactions in a block matching the given block number.
    ##
    ## data: integer of a block number, or the string "earliest", "latest" or "pending", as in the default block parameter.
    ## Returns integer of the number of transactions in this block.
    let
      header  = chainDB.headerFromTag(quantityTag)
      txCount = chainDB.getTransactionCount(header.txRoot)
    Web3Quantity(txCount)

  server.rpc("eth_getUncleCountByBlockHash") do(data: Hash32) -> Web3Quantity:
    ## Returns the number of uncles in a block from a block matching the given block hash.
    ##
    ## data: hash of a block.
    ## Returns integer of the number of uncles in this block.
    let
      blockHash   = data
      header      = chainDB.getBlockHeader(blockHash)
      unclesCount = chainDB.getUnclesCount(header.ommersHash)
    Web3Quantity(unclesCount)

  server.rpc("eth_getUncleCountByBlockNumber") do(quantityTag: BlockTag) -> Web3Quantity:
    ## Returns the number of uncles in a block from a block matching the given block number.
    ##
    ## quantityTag: integer of a block number, or the string "latest", "earliest" or "pending", see the default block parameter.
    ## Returns integer of uncles in this block.
    let
      header      = chainDB.headerFromTag(quantityTag)
      unclesCount = chainDB.getUnclesCount(header.ommersHash)
    Web3Quantity(unclesCount)

  server.rpc("eth_getCode") do(data: eth_types.Address, quantityTag: BlockTag) -> seq[byte]:
    ## Returns code at a given address.
    ##
    ## data: address
    ## quantityTag: integer block number, or the string "latest", "earliest" or "pending", see the default block parameter.
    ## Returns the code from the given address.
    let
      accDB   = stateDBFromTag(quantityTag)
      address = data
    accDB.getCode(address).bytes()

  template sign(privateKey: PrivateKey, message: string): seq[byte] =
    # message length encoded as ASCII representation of decimal
    let msgData = "\x19Ethereum Signed Message:\n" & $message.len & message
    @(sign(privateKey, msgData.toBytes()).toRaw())

  server.rpc("eth_sign") do(data: eth_types.Address, message: seq[byte]) -> seq[byte]:
    ## The sign method calculates an Ethereum specific signature with: sign(keccak256("\x19Ethereum Signed Message:\n" + len(message) + message))).
    ## By adding a prefix to the message makes the calculated signature recognisable as an Ethereum specific signature.
    ## This prevents misuse where a malicious DApp can sign arbitrary data (e.g. transaction) and use the signature to impersonate the victim.
    ## Note the address to sign with must be unlocked.
    ##
    ## data: address.
    ## message: message to sign.
    ## Returns signature.
    let
      address = data
      acc     = ctx.am.getAccount(address).tryGet()

    if not acc.unlocked:
      raise newException(ValueError, "Account locked, please unlock it first")
    sign(acc.privateKey, cast[string](message))

  server.rpc("eth_signTransaction") do(data: TransactionArgs) -> seq[byte]:
    ## Signs a transaction that can be submitted to the network at a later time using with
    ## eth_sendRawTransaction
    let
      address = data.`from`.get()
      acc     = ctx.am.getAccount(address).tryGet()

    if not acc.unlocked:
      raise newException(ValueError, "Account locked, please unlock it first")

    let
      accDB    = stateDBFromTag(blockId("latest"))
      tx       = unsignedTx(data, chainDB, accDB.getNonce(address) + 1, com.chainId)
      eip155   = com.isEIP155(com.syncCurrent)
      signedTx = signTransaction(tx, acc.privateKey, eip155)
    result    = rlp.encode(signedTx)

  server.rpc("eth_sendTransaction") do(data: TransactionArgs) -> Hash32:
    ## Creates new message call transaction or a contract creation, if the data field contains code.
    ##
    ## obj: the transaction object.
    ## Returns the transaction hash, or the zero hash if the transaction is not yet available.
    ## Note: Use eth_getTransactionReceipt to get the contract address, after the transaction was mined, when you created a contract.
    let
      address = data.`from`.get()
      acc     = ctx.am.getAccount(address).tryGet()

    if not acc.unlocked:
      raise newException(ValueError, "Account locked, please unlock it first")

    let
      accDB    = stateDBFromTag(blockId("latest"))
      tx       = unsignedTx(data, chainDB, accDB.getNonce(address) + 1, com.chainId)
      eip155   = com.isEIP155(com.syncCurrent)
      signedTx = signTransaction(tx, acc.privateKey, eip155)
      networkPayload =
        if signedTx.txType == TxEip4844:
          if data.blobs.isNone or data.commitments.isNone or data.proofs.isNone:
            raise newException(ValueError, "EIP-4844 transaction needs blobs")
          if data.blobs.get.len != signedTx.versionedHashes.len:
            raise newException(ValueError, "Incorrect number of blobs")
          if data.commitments.get.len != signedTx.versionedHashes.len:
            raise newException(ValueError, "Incorrect number of commitments")
          if data.proofs.get.len != signedTx.versionedHashes.len:
            raise newException(ValueError, "Incorrect number of proofs")
          NetworkPayload(
            blobs: data.blobs.get.mapIt it.NetworkBlob,
            commitments: data.commitments.get,
            proofs: data.proofs.get)
        else:
          if data.blobs.isSome or data.commitments.isSome or data.proofs.isSome:
            raise newException(ValueError, "Blobs require EIP-4844 transaction")
          nil
      pooledTx = PooledTransaction(tx: signedTx, networkPayload: networkPayload)

    txPool.add(pooledTx)
    rlpHash(signedTx)

  server.rpc("eth_sendRawTransaction") do(txBytes: seq[byte]) -> Hash32:
    ## Creates new message call transaction or a contract creation for signed transactions.
    ##
    ## data: the signed transaction data.
    ## Returns the transaction hash, or the zero hash if the transaction is not yet available.
    ## Note: Use eth_getTransactionReceipt to get the contract address, after the transaction was mined, when you created a contract.
    let
      pooledTx = decodePooledTx(txBytes)
      txHash   = rlpHash(pooledTx)

    txPool.add(pooledTx)
    let res = txPool.inPoolAndReason(txHash)
    if res.isErr:
      raise newException(ValueError, res.error)
    txHash

  server.rpc("eth_call") do(args: TransactionArgs, quantityTag: BlockTag) -> seq[byte]:
    ## Executes a new message call immediately without creating a transaction on the block chain.
    ##
    ## call: the transaction call object.
    ## quantityTag:  integer block number, or the string "latest", "earliest" or "pending", see the default block parameter.
    ## Returns the return value of executed contract.
    let
      header   = headerFromTag(chainDB, quantityTag)
      res      = rpcCallEvm(args, header, com).valueOr:
                   raise newException(ValueError, "rpcCallEvm error: " & $error.code)
    res.output

  server.rpc("eth_estimateGas") do(args: TransactionArgs) -> Web3Quantity:
    ## Generates and returns an estimate of how much gas is necessary to allow the transaction to complete.
    ## The transaction will not be added to the blockchain. Note that the estimate may be significantly more than
    ## the amount of gas actually used by the transaction, for a variety of reasons including EVM mechanics and node performance.
    ##
    ## args: the transaction call object.
    ## quantityTag:  integer block number, or the string "latest", "earliest" or "pending", see the default block parameter.
    ## Returns the amount of gas used.
    let
      header   = chainDB.headerFromTag(blockId("latest"))
      # TODO: DEFAULT_RPC_GAS_CAP should configurable
      gasUsed  = rpcEstimateGas(args, header, com, DEFAULT_RPC_GAS_CAP).valueOr:
                   raise newException(ValueError, "rpcEstimateGas error: " & $error.code)
    w3Qty(gasUsed)

  server.rpc("eth_getBlockByHash") do(data: Hash32, fullTransactions: bool) -> BlockObject:
    ## Returns information about a block by hash.
    ##
    ## data: Hash of a block.
    ## fullTransactions: If true it returns the full transaction objects, if false only the hashes of the transactions.
    ## Returns BlockObject or nil when no block was found.
    var
      header:Header
      hash = data

    if chainDB.getBlockHeader(hash, header):
      populateBlockObject(header, chainDB, fullTransactions)
    else:
      nil

  server.rpc("eth_getBlockByNumber") do(quantityTag: BlockTag, fullTransactions: bool) -> BlockObject:
    ## Returns information about a block by block number.
    ##
    ## quantityTag: integer of a block number, or the string "earliest", "latest" or "pending", as in the default block parameter.
    ## fullTransactions: If true it returns the full transaction objects, if false only the hashes of the transactions.
    ## Returns BlockObject or nil when no block was found.
    try:
      let header = chainDB.headerFromTag(quantityTag)
      populateBlockObject(header, chainDB, fullTransactions)
    except CatchableError:
      nil

  server.rpc("eth_getTransactionByHash") do(data: Hash32) -> TransactionObject:
    ## Returns the information about a transaction requested by transaction hash.
    ##
    ## data: hash of a transaction.
    ## Returns requested transaction information.
    let txHash = data
    let res = txPool.getItem(txHash)
    if res.isOk:
      return populateTransactionObject(res.get().tx)

    let txDetails = chainDB.getTransactionKey(txHash)
    if txDetails.index < 0:
      return nil

    let header = chainDB.getBlockHeader(txDetails.blockNumber)
    var tx: Transaction
    if chainDB.getTransactionByIndex(header.txRoot, uint16(txDetails.index), tx):
      result = populateTransactionObject(tx, Opt.some(header), Opt.some(txDetails.index))

  server.rpc("eth_getTransactionByBlockHashAndIndex") do(data: Hash32, quantity: Web3Quantity) -> TransactionObject:
    ## Returns information about a transaction by block hash and transaction index position.
    ##
    ## data: hash of a block.
    ## quantity: integer of the transaction index position.
    ## Returns  requested transaction information.
    let index  = uint64(quantity)
    var header:Header
    if not chainDB.getBlockHeader(data, header):
      return nil

    var tx: Transaction
    if chainDB.getTransactionByIndex(header.txRoot, uint16(index), tx):
      populateTransactionObject(tx, Opt.some(header), Opt.some(index))
    else:
      nil

  server.rpc("eth_getTransactionByBlockNumberAndIndex") do(quantityTag: BlockTag, quantity: Web3Quantity) -> TransactionObject:
    ## Returns information about a transaction by block number and transaction index position.
    ##
    ## quantityTag: a block number, or the string "earliest", "latest" or "pending", as in the default block parameter.
    ## quantity: the transaction index position.
    let
      header = chainDB.headerFromTag(quantityTag)
      index  = uint64(quantity)

    var tx: Transaction
    if chainDB.getTransactionByIndex(header.txRoot, uint16(index), tx):
      populateTransactionObject(tx, Opt.some(header), Opt.some(index))
    else:
      nil

  server.rpc("eth_getTransactionReceipt") do(data: Hash32) -> ReceiptObject:
    ## Returns the receipt of a transaction by transaction hash.
    ##
    ## data: hash of a transaction.
    ## Returns transaction receipt.

    let txDetails = chainDB.getTransactionKey(data)
    if txDetails.index < 0:
      return nil

    let header = chainDB.getBlockHeader(txDetails.blockNumber)
    var tx: Transaction
    if not chainDB.getTransactionByIndex(header.txRoot, uint16(txDetails.index), tx):
      return nil

    var
      idx = 0'u64
      prevGasUsed = GasInt(0)

    for receipt in chainDB.getReceipts(header.receiptsRoot):
      let gasUsed = receipt.cumulativeGasUsed - prevGasUsed
      prevGasUsed = receipt.cumulativeGasUsed
      if idx == txDetails.index:
        return populateReceipt(receipt, gasUsed, tx, txDetails.index, header)
      idx.inc

  server.rpc("eth_getUncleByBlockHashAndIndex") do(data: Hash32, quantity: Web3Quantity) -> BlockObject:
    ## Returns information about a uncle of a block by hash and uncle index position.
    ##
    ## data: hash of block.
    ## quantity: the uncle's index position.
    ## Returns BlockObject or nil when no block was found.
    let index  = uint64(quantity)
    var header:Header
    if not chainDB.getBlockHeader(data, header):
      return nil

    let uncles = chainDB.getUncles(header.ommersHash)
    if index < 0 or index >= uncles.len.uint64:
      return nil

    result = populateBlockObject(uncles[index], chainDB, false, true)
    result.totalDifficulty = chainDB.getScore(header.blockHash).valueOr(0.u256)

  server.rpc("eth_getUncleByBlockNumberAndIndex") do(quantityTag: BlockTag, quantity: Web3Quantity) -> BlockObject:
    # Returns information about a uncle of a block by number and uncle index position.
    ##
    ## quantityTag: a block number, or the string "earliest", "latest" or "pending", as in the default block parameter.
    ## quantity: the uncle's index position.
    ## Returns BlockObject or nil when no block was found.
    let
      index  = uint64(quantity)
      header = chainDB.headerFromTag(quantityTag)
      uncles = chainDB.getUncles(header.ommersHash)

    if index < 0 or index >= uncles.len.uint64:
      return nil

    result = populateBlockObject(uncles[index], chainDB, false, true)
    result.totalDifficulty = chainDB.getScore(header.blockHash).valueOr(0.u256)

  proc getLogsForBlock(
      chain: CoreDbRef,
      hash: Hash32,
      header:Header,
      opts: FilterOptions): seq[FilterLog]
        {.gcsafe, raises: [RlpError,BlockNotFound].} =
    if headerBloomFilter(header, opts.address, opts.topics):
      let blockBody = chain.getBlockBody(hash)
      let receipts = chain.getReceipts(header.receiptsRoot)
      # Note: this will hit assertion error if number of block transactions
      # do not match block receipts.
      # Although this is fine as number of receipts should always match number
      # of transactions
      let logs = deriveLogs(header, blockBody.transactions, receipts)
      let filteredLogs = filterLogs(logs, opts.address, opts.topics)
      return filteredLogs
    else:
      return @[]

  proc getLogsForRange(
      chain: CoreDbRef,
      start: common.BlockNumber,
      finish: common.BlockNumber,
      opts: FilterOptions): seq[FilterLog]
        {.gcsafe, raises: [RlpError,BlockNotFound].} =
    var logs = newSeq[FilterLog]()
    var i = start
    while i <= finish:
      let res = chain.getBlockHeaderWithHash(i)
      if res.isSome():
        let (hash, header)= res.unsafeGet()
        let filtered = chain.getLogsForBlock(header, hash, opts)
        logs.add(filtered)
      else:
        #
        return logs
      i = i + 1
    return logs

  server.rpc("eth_getLogs") do(filterOptions: FilterOptions) -> seq[FilterLog]:
    ## filterOptions: settings for this filter.
    ## Returns a list of all logs matching a given filter object.
    ## TODO: Current implementation is pretty naive and not efficient
    ## as it requires to fetch all transactions and all receipts from database.
    ## Other clients (Geth):
    ## - Store logs related data in receipts.
    ## - Have separate indexes for Logs in given block
    ## Both of those changes require improvements to the way how we keep our data
    ## in Nimbus.
    if filterOptions.blockHash.isSome():
      let hash = filterOptions.blockHash.unsafeGet()
      let header = chainDB.getBlockHeader(hash)
      return getLogsForBlock(chainDB, hash, header, filterOptions)
    else:
      # TODO: do something smarter with tags. It would be the best if
      # tag would be an enum (Earliest, Latest, Pending, Number), and all operations
      # would operate on this enum instead of raw strings. This change would need
      # to be done on every endpoint to be consistent.
      let fromHeader = chainDB.headerFromTag(filterOptions.fromBlock)
      let toHeader = chainDB.headerFromTag(filterOptions.toBlock)

      # Note: if fromHeader.number > toHeader.number, no logs will be
      # returned. This is consistent with, what other ethereum clients return
      let logs = chainDB.getLogsForRange(
        fromHeader.number,
        toHeader.number,
        filterOptions
      )
      return logs

  server.rpc("eth_getProof") do(data: eth_types.Address, slots: seq[UInt256], quantityTag: BlockTag) -> ProofResponse:
    ## Returns information about an account and storage slots (if the account is a contract
    ## and the slots are requested) along with account and storage proofs which prove the
    ## existence of the values in the state.
    ## See spec here: https://eips.ethereum.org/EIPS/eip-1186
    ##
    ## data: address of the account.
    ## slots: integers of the positions in the storage to return with storage proofs.
    ## quantityTag: integer block number, or the string "latest", "earliest" or "pending", see the default block parameter.
    ## Returns: the proof response containing the account, account proof and storage proof

    let
      accDB = stateDBFromTag(quantityTag)
      address = data

    getProof(accDB, address, slots)

  server.rpc("eth_getBlockReceipts") do(quantityTag: BlockTag) -> Opt[seq[ReceiptObject]]:
    ## Returns the receipts of a block.
    try:
      let header = chainDB.headerFromTag(quantityTag)
      var
        prevGasUsed = GasInt(0)
        recs: seq[ReceiptObject]
        txs: seq[Transaction]
        index = 0'u64

      for tx in chainDB.getBlockTransactions(header):
        txs.add tx

      for receipt in chainDB.getReceipts(header.receiptsRoot):
        let gasUsed = receipt.cumulativeGasUsed - prevGasUsed
        prevGasUsed = receipt.cumulativeGasUsed
        recs.add populateReceipt(receipt, gasUsed, txs[index], index, header)
        inc index

      return Opt.some(recs)
    except CatchableError:
      return Opt.none(seq[ReceiptObject])

  server.rpc("eth_createAccessList") do(args: TransactionArgs, quantityTag: BlockTag) -> AccessListResult:
    ## Generates an access list for a transaction.
    try:
      let
        header = chainDB.headerFromTag(quantityTag)
      return createAccessList(header, com, args)
    except CatchableError as exc:
      return AccessListResult(
        error: Opt.some("createAccessList error: " & exc.msg),
      )

  server.rpc("eth_blobBaseFee") do() -> Web3Quantity:
    ## Returns the base fee per blob gas in wei.
    let header = chainDB.headerFromTag(blockId("latest"))
    if header.blobGasUsed.isNone:
      raise newException(ValueError, "blobGasUsed missing from latest header")
    if header.excessBlobGas.isNone:
      raise newException(ValueError, "excessBlobGas missing from latest header")
    let blobBaseFee = getBlobBaseFee(header.excessBlobGas.get) * header.blobGasUsed.get.u256
    if blobBaseFee > high(uint64).u256:
      raise newException(ValueError, "blobBaseFee is bigger than uint64.max")
    return w3Qty blobBaseFee.truncate(uint64)

  server.rpc("eth_feeHistory") do(blockCount: Quantity,
                                  newestBlock: BlockTag,
                                  rewardPercentiles: Opt[seq[float64]]) -> FeeHistoryResult:
    let
      blocks = blockCount.uint64
      percentiles = rewardPercentiles.get(newSeq[float64]())
      res = feeHistory(oracle, blocks, newestBlock, percentiles)
    if res.isErr:
      raise newException(ValueError, res.error)
    return res.get