path: root/rpc/api/eth_args.go

package api

import (
    "encoding/json"
    "fmt"
    "math/big"
    "strconv"
    "strings"

    "github.com/ethereum/go-ethereum/common"
    "github.com/ethereum/go-ethereum/core/state"
    "github.com/ethereum/go-ethereum/core/types"
    "github.com/ethereum/go-ethereum/rpc/shared"
)

const (
    defaultLogLimit  = 100
    defaultLogOffset = 0
)

type GetBalanceArgs struct {
    Address     string
    BlockNumber int64
}

func (args *GetBalanceArgs) UnmarshalJSON(b []byte) (err error) {
    var obj []interface{}
    if err := json.Unmarshal(b, &obj); err != nil {
        return shared.NewDecodeParamError(err.Error())
    }

    if len(obj) < 1 {
        return shared.NewInsufficientParamsError(len(obj), 1)
    }

    addstr, ok := obj[0].(string)
    if !ok {
        return shared.NewInvalidTypeError("address", "not a string")
    }
    args.Address = addstr

    if len(obj) > 1 {
        if err := blockHeight(obj[1], &args.BlockNumber); err != nil {
            return err
        }
    } else {
        args.BlockNumber = -1
    }

    return nil
}

type GetStorageArgs struct {
    Address     string
    BlockNumber int64
}

func (args *GetStorageArgs) UnmarshalJSON(b []byte) (err error) {
    var obj []interface{}
    if err := json.Unmarshal(b, &obj); err != nil {
        return shared.NewDecodeParamError(err.Error())
    }

    if len(obj) < 1 {
        return shared.NewInsufficientParamsError(len(obj), 1)
    }

    addstr, ok := obj[0].(string)
    if !ok {
        return shared.NewInvalidTypeError("address", "not a string")
    }
    args.Address = addstr

    if len(obj) > 1 {
        if err := blockHeight(obj[1], &args.BlockNumber); err != nil {
            return err
        }
    } else {
        args.BlockNumber = -1
    }

    return nil
}

type GetStorageAtArgs struct {
    Address     string
    BlockNumber int64
    Key         string
}

func (args *GetStorageAtArgs) UnmarshalJSON(b []byte) (err error) {
    var obj []interface{}
    if err := json.Unmarshal(b, &obj); err != nil {
        return shared.NewDecodeParamError(err.Error())
    }

    if len(obj) < 2 {
        return shared.NewInsufficientParamsError(len(obj), 2)
    }

    addstr, ok := obj[0].(string)
    if !ok {
        return shared.NewInvalidTypeError("address", "not a string")
    }
    args.Address = addstr

    keystr, ok := obj[1].(string)
    if !ok {
        return shared.NewInvalidTypeError("key", "not a string")
    }
    args.Key = keystr

    if len(obj) > 2 {
        if err := blockHeight(obj[2], &args.BlockNumber); err != nil {
            return err
        }
    } else {
        args.BlockNumber = -1
    }

    return nil
}

type GetTxCountArgs struct {
    Address     string
    BlockNumber int64
}

func (args *GetTxCountArgs) UnmarshalJSON(b []byte) (err error) {
    var obj []interface{}
    if err := json.Unmarshal(b, &obj); err != nil {
        return shared.NewDecodeParamError(err.Error())
    }

    if len(obj) < 1 {
        return shared.NewInsufficientParamsError(len(obj), 1)
    }

    addstr, ok := obj[0].(string)
    if !ok {
        return shared.NewInvalidTypeError("address", "not a string")
    }
    args.Address = addstr

    if len(obj) > 1 {
        if err := blockHeight(obj[1], &args.BlockNumber); err != nil {
            return err
        }
    } else {
        args.BlockNumber = -1
    }

    return nil
}

type HashArgs struct {
    Hash string
}

func (args *HashArgs) UnmarshalJSON(b []byte) (err error) {
    var obj []interface{}
    if err := json.Unmarshal(b, &obj); err != nil {
        return shared.NewDecodeParamError(err.Error())
    }

    if len(obj) < 1 {
        return shared.NewInsufficientParamsError(len(obj), 1)
    }

    arg0, ok := obj[0].(string)
    if !ok {
        return shared.NewInvalidTypeError("hash", "not a string")
    }
    args.Hash = arg0

    return nil
}

type BlockNumArg struct {
    BlockNumber int64
}

func (args *BlockNumArg) UnmarshalJSON(b []byte) (err error) {
    var obj []interface{}
    if err := json.Unmarshal(b, &obj); err != nil {
        return shared.NewDecodeParamError(err.Error())
    }

    if len(obj) < 1 {
        return shared.NewInsufficientParamsError(len(obj), 1)
    }

    if err := blockHeight(obj[0], &args.BlockNumber); err != nil {
        return err
    }

    return nil
}

type GetDataArgs struct {
    Address     string
    BlockNumber int64
}

func (args *GetDataArgs) UnmarshalJSON(b []byte) (err error) {
    var obj []interface{}
    if err := json.Unmarshal(b, &obj); err != nil {
        return shared.NewDecodeParamError(err.Error())
    }

    if len(obj) < 1 {
        return shared.NewInsufficientParamsError(len(obj), 1)
    }

    addstr, ok := obj[0].(string)
    if !ok {
        return shared.NewInvalidTypeError("address", "not a string")
    }
    args.Address = addstr

    if len(obj) > 1 {
        if err := blockHeight(obj[1], &args.BlockNumber); err != nil {
            return err
        }
    } else {
        args.BlockNumber = -1
    }

    return nil
}

type NewDataArgs struct {
    Data string
}

func (args *NewDataArgs) UnmarshalJSON(b []byte) (err error) {
    var obj []interface{}

    if err := json.Unmarshal(b, &obj); err != nil {
        return shared.NewDecodeParamError(err.Error())
    }

    // Check for sufficient params
    if len(obj) < 1 {
        return shared.NewInsufficientParamsError(len(obj), 1)
    }

    data, ok := obj[0].(string)
    if !ok {
        return shared.NewInvalidTypeError("data", "not a string")
    }
    args.Data = data

    if len(args.Data) == 0 {
        return shared.NewValidationError("data", "is required")
    }

    return nil
}

type NewSigArgs struct {
    From string
    Data string
}

func (args *NewSigArgs) UnmarshalJSON(b []byte) (err error) {
    var obj []interface{}

    if err := json.Unmarshal(b, &obj); err != nil {
        return shared.NewDecodeParamError(err.Error())
    }

    // Check for sufficient params
    if len(obj) < 1 {
        return shared.NewInsufficientParamsError(len(obj), 1)
    }

    from, ok := obj[0].(string)
    if !ok {
        return shared.NewInvalidTypeError("from", "not a string")
    }
    args.From = from

    if len(args.From) == 0 {
        return shared.NewValidationError("from", "is required")
    }

    data, ok := obj[1].(string)
    if !ok {
        return shared.NewInvalidTypeError("data", "not a string")
    }
    args.Data = data

    if len(args.Data) == 0 {
        return shared.NewValidationError("data", "is required")
    }

    return nil
}

type NewTxArgs struct {
    From     string
    To       string
    Nonce    *big.Int
    Value    *big.Int
    Gas      *big.Int
    GasPrice *big.Int
    Data     string

    BlockNumber int64
}

func (args *NewTxArgs) UnmarshalJSON(b []byte) (err error) {
    var obj []json.RawMessage
    var ext struct {
        From     string
        To       string
        Nonce    interface{}
        Value    interface{}
        Gas      interface{}
        GasPrice interface{}
        Data     string
    }

    // Decode byte slice to array of RawMessages
    if err := json.Unmarshal(b, &obj); err != nil {
        return shared.NewDecodeParamError(err.Error())
    }

    // Check for sufficient params
    if len(obj) < 1 {
        return shared.NewInsufficientParamsError(len(obj), 1)
    }

    // Decode 0th RawMessage to temporary struct
    if err := json.Unmarshal(obj[0], &ext); err != nil {
        return shared.NewDecodeParamError(err.Error())
    }

    if len(ext.From) == 0 {
        return shared.NewValidationError("from", "is required")
    }

    args.From = ext.From
    args.To = ext.To
    args.Data = ext.Data

    var num *big.Int
    if ext.Nonce != nil {
        num, err = numString(ext.Nonce)
        if err != nil {
            return err
        }
    }
    args.Nonce = num

    if ext.Value == nil {
        num = big.NewInt(0)
    } else {
        num, err = numString(ext.Value)
        if err != nil {
            return err
        }
    }
    args.Value = num

    num = nil
    if ext.Gas != nil {
        if num, err = numString(ext.Gas); err != nil {
            return err
        }
    }
    args.Gas = num

    num = nil
    if ext.GasPrice != nil {
        if num, err = numString(ext.GasPrice); err != nil {
            return err
        }
    }
    args.GasPrice = num

    // Check for optional BlockNumber param
    if len(obj) > 1 {
        if err := blockHeightFromJson(obj[1], &args.BlockNumber); err != nil {
            return err
        }
    } else {
        args.BlockNumber = -1
    }

    return nil
}

type SourceArgs struct {
    Source string
}

func (args *SourceArgs) UnmarshalJSON(b []byte) (err error) {
    var obj []interface{}
    if err := json.Unmarshal(b, &obj); err != nil {
        return shared.NewDecodeParamError(err.Error())
    }

    if len(obj) < 1 {
        return shared.NewInsufficientParamsError(len(obj), 1)
    }

    arg0, ok := obj[0].(string)
    if !ok {
        return shared.NewInvalidTypeError("source code", "not a string")
    }
    args.Source = arg0

    return nil
}

type CallArgs struct {
    From     string
    To       string
    Value    *big.Int
    Gas      *big.Int
    GasPrice *big.Int
    Data     string

    BlockNumber int64
}

func (args *CallArgs) UnmarshalJSON(b []byte) (err error) {
    var obj []json.RawMessage
    var ext struct {
        From     string
        To       string
        Value    interface{}
        Gas      interface{}
        GasPrice interface{}
        Data     string
    }

    // Decode byte slice to array of RawMessages
    if err := json.Unmarshal(b, &obj); err != nil {
        return shared.NewDecodeParamError(err.Error())
    }

    // Check for sufficient params
    if len(obj) < 1 {
        return shared.NewInsufficientParamsError(len(obj), 1)
    }

    // Decode 0th RawMessage to temporary struct
    if err := json.Unmarshal(obj[0], &ext); err != nil {
        return shared.NewDecodeParamError(err.Error())
    }

    args.From = ext.From

    if len(ext.To) == 0 {
        return shared.NewValidationError("to", "is required")
    }
    args.To = ext.To

    var num *big.Int
    if ext.Value == nil {
        num = big.NewInt(0)
    } else {
        if num, err = numString(ext.Value); err != nil {
            return err
        }
    }
    args.Value = num

    if ext.Gas != nil {
        if num, err = numString(ext.Gas); err != nil {
            return err
        }
    } else {
        num = nil
    }
    args.Gas = num

    if ext.GasPrice != nil {
        if num, err = numString(ext.GasPrice); err != nil {
            return err
        }
    } else {
        num = nil
    }
    args.GasPrice = num

    args.Data = ext.Data

    // Check for optional BlockNumber param
    if len(obj) > 1 {
        if err := blockHeightFromJson(obj[1], &args.BlockNumber); err != nil {
            return err
        }
    } else {
        args.BlockNumber = -1
    }

    return nil
}

type HashIndexArgs struct {
    Hash  string
    Index int64
}

func (args *HashIndexArgs) UnmarshalJSON(b []byte) (err error) {
    var obj []interface{}
    if err := json.Unmarshal(b, &obj); err != nil {
        return shared.NewDecodeParamError(err.Error())
    }

    if len(obj) < 2 {
        return shared.NewInsufficientParamsError(len(obj), 2)
    }

    arg0, ok := obj[0].(string)
    if !ok {
        return shared.NewInvalidTypeError("hash", "not a string")
    }
    args.Hash = arg0

    arg1, ok := obj[1].(string)
    if !ok {
        return shared.NewInvalidTypeError("index", "not a string")
    }
    args.Index = common.Big(arg1).Int64()

    return nil
}

type BlockNumIndexArgs struct {
    BlockNumber int64
    Index       int64
}

func (args *BlockNumIndexArgs) UnmarshalJSON(b []byte) (err error) {
    var obj []interface{}
    if err := json.Unmarshal(b, &obj); err != nil {
        return shared.NewDecodeParamError(err.Error())
    }

    if len(obj) < 2 {
        return shared.NewInsufficientParamsError(len(obj), 2)
    }

    if err := blockHeight(obj[0], &args.BlockNumber); err != nil {
        return err
    }

    var arg1 *big.Int
    if arg1, err = numString(obj[1]); err != nil {
        return err
    }
    args.Index = arg1.Int64()

    return nil
}

type GetBlockByHashArgs struct {
    BlockHash  string
    IncludeTxs bool
}

func (args *GetBlockByHashArgs) UnmarshalJSON(b []byte) (err error) {
    var obj []interface{}

    if err := json.Unmarshal(b, &obj); err != nil {
        return shared.NewDecodeParamError(err.Error())
    }

    if len(obj) < 2 {
        return shared.NewInsufficientParamsError(len(obj), 2)
    }

    argstr, ok := obj[0].(string)
    if !ok {
        return shared.NewInvalidTypeError("blockHash", "not a string")
    }
    args.BlockHash = argstr

    args.IncludeTxs = obj[1].(bool)

    return nil
}

type GetBlockByNumberArgs struct {
    BlockNumber int64
    IncludeTxs  bool
}

func (args *GetBlockByNumberArgs) UnmarshalJSON(b []byte) (err error) {
    var obj []interface{}
    if err := json.Unmarshal(b, &obj); err != nil {
        return shared.NewDecodeParamError(err.Error())
    }

    if len(obj) < 2 {
        return shared.NewInsufficientParamsError(len(obj), 2)
    }

    if err := blockHeight(obj[0], &args.BlockNumber); err != nil {
        return err
    }

    args.IncludeTxs = obj[1].(bool)

    return nil
}

type BlockFilterArgs struct {
    Earliest int64
    Latest   int64
    Address  []string
    Topics   [][]string
    Skip     int
    Max      int
}

func (args *BlockFilterArgs) UnmarshalJSON(b []byte) (err error) {
    var obj []struct {
        FromBlock interface{} `json:"fromBlock"`
        ToBlock   interface{} `json:"toBlock"`
        Limit     interface{} `json:"limit"`
        Offset    interface{} `json:"offset"`
        Address   interface{} `json:"address"`
        Topics    interface{} `json:"topics"`
    }

    if err = json.Unmarshal(b, &obj); err != nil {
        return shared.NewDecodeParamError(err.Error())
    }

    if len(obj) < 1 {
        return shared.NewInsufficientParamsError(len(obj), 1)
    }

    // args.Earliest, err = toNumber(obj[0].ToBlock)
    // if err != nil {
    //  return shared.NewDecodeParamError(fmt.Sprintf("FromBlock %v", err))
    // }
    // args.Latest, err = toNumber(obj[0].FromBlock)
    // if err != nil {
    //  return shared.NewDecodeParamError(fmt.Sprintf("ToBlock %v", err))

    var num int64
    var numBig *big.Int

    // if blank then latest
    if obj[0].FromBlock == nil {
        num = -1
    } else {
        if err := blockHeight(obj[0].FromBlock, &num); err != nil {
            return err
        }
    }
    // if -2 or other "silly" number, use latest
    if num < 0 {
        args.Earliest = -1 //latest block
    } else {
        args.Earliest = num
    }

    // if blank than latest
    if obj[0].ToBlock == nil {
        num = -1
    } else {
        if err := blockHeight(obj[0].ToBlock, &num); err != nil {
            return err
        }
    }
    args.Latest = num

    if obj[0].Limit == nil {
        numBig = big.NewInt(defaultLogLimit)
    } else {
        if numBig, err = numString(obj[0].Limit); err != nil {
            return err
        }
    }
    args.Max = int(numBig.Int64())

    if obj[0].Offset == nil {
        numBig = big.NewInt(defaultLogOffset)
    } else {
        if numBig, err = numString(obj[0].Offset); err != nil {
            return err
        }
    }
    args.Skip = int(numBig.Int64())

    if obj[0].Address != nil {
        marg, ok := obj[0].Address.([]interface{})
        if ok {
            v := make([]string, len(marg))
            for i, arg := range marg {
                argstr, ok := arg.(string)
                if !ok {
                    return shared.NewInvalidTypeError(fmt.Sprintf("address[%d]", i), "is not a string")
                }
                v[i] = argstr
            }
            args.Address = v
        } else {
            argstr, ok := obj[0].Address.(string)
            if ok {
                v := make([]string, 1)
                v[0] = argstr
                args.Address = v
            } else {
                return shared.NewInvalidTypeError("address", "is not a string or array")
            }
        }
    }

    if obj[0].Topics != nil {
        other, ok := obj[0].Topics.([]interface{})
        if ok {
            topicdbl := make([][]string, len(other))
            for i, iv := range other {
                if argstr, ok := iv.(string); ok {
                    // Found a string, push into first element of array
                    topicsgl := make([]string, 1)
                    topicsgl[0] = argstr
                    topicdbl[i] = topicsgl
                } else if argarray, ok := iv.([]interface{}); ok {
                    // Found an array of other
                    topicdbl[i] = make([]string, len(argarray))
                    for j, jv := range argarray {
                        if v, ok := jv.(string); ok {
                            topicdbl[i][j] = v
                        } else if jv == nil {
                            topicdbl[i][j] = ""
                        } else {
                            return shared.NewInvalidTypeError(fmt.Sprintf("topic[%d][%d]", i, j), "is not a string")
                        }
                    }
                } else if iv == nil {
                    topicdbl[i] = []string{""}
                } else {
                    return shared.NewInvalidTypeError(fmt.Sprintf("topic[%d]", i), "not a string or array")
                }
            }
            args.Topics = topicdbl
            return nil
        } else {
            return shared.NewInvalidTypeError("topic", "is not a string or array")
        }
    }

    return nil
}

type FilterIdArgs struct {
    Id int
}

func (args *FilterIdArgs) UnmarshalJSON(b []byte) (err error) {
    var obj []interface{}
    if err := json.Unmarshal(b, &obj); err != nil {
        return shared.NewDecodeParamError(err.Error())
    }

    if len(obj) < 1 {
        return shared.NewInsufficientParamsError(len(obj), 1)
    }

    var num *big.Int
    if num, err = numString(obj[0]); err != nil {
        return err
    }
    args.Id = int(num.Int64())

    return nil
}

type LogRes struct {
    Address          *hexdata   `json:"address"`
    Topics           []*hexdata `json:"topics"`
    Data             *hexdata   `json:"data"`
    BlockNumber      *hexnum    `json:"blockNumber"`
    LogIndex         *hexnum    `json:"logIndex"`
    BlockHash        *hexdata   `json:"blockHash"`
    TransactionHash  *hexdata   `json:"transactionHash"`
    TransactionIndex *hexnum    `json:"transactionIndex"`
}

func NewLogRes(log *state.Log) LogRes {
    var l LogRes
    l.Topics = make([]*hexdata, len(log.Topics))
    for j, topic := range log.Topics {
        l.Topics[j] = newHexData(topic)
    }
    l.Address = newHexData(log.Address)
    l.Data = newHexData(log.Data)
    l.BlockNumber = newHexNum(log.Number)
    l.LogIndex = newHexNum(log.Index)
    l.TransactionHash = newHexData(log.TxHash)
    l.TransactionIndex = newHexNum(log.TxIndex)
    l.BlockHash = newHexData(log.BlockHash)

    return l
}

func NewLogsRes(logs state.Logs) (ls []LogRes) {
    ls = make([]LogRes, len(logs))

    for i, log := range logs {
        ls[i] = NewLogRes(log)
    }

    return
}

func NewHashesRes(hs []common.Hash) []string {
    hashes := make([]string, len(hs))

    for i, hash := range hs {
        hashes[i] = hash.Hex()
    }

    return hashes
}

type SubmitWorkArgs struct {
    Nonce  uint64
    Header string
    Digest string
}

func (args *SubmitWorkArgs) UnmarshalJSON(b []byte) (err error) {
    var obj []interface{}
    if err = json.Unmarshal(b, &obj); err != nil {
        return shared.NewDecodeParamError(err.Error())
    }

    if len(obj) < 3 {
        return shared.NewInsufficientParamsError(len(obj), 3)
    }

    var objstr string
    var ok bool
    if objstr, ok = obj[0].(string); !ok {
        return shared.NewInvalidTypeError("nonce", "not a string")
    }

    args.Nonce = common.String2Big(objstr).Uint64()
    if objstr, ok = obj[1].(string); !ok {
        return shared.NewInvalidTypeError("header", "not a string")
    }

    args.Header = objstr

    if objstr, ok = obj[2].(string); !ok {
        return shared.NewInvalidTypeError("digest", "not a string")
    }

    args.Digest = objstr

    return nil
}

type tx struct {
    tx *types.Transaction

    To       string
    From     string
    Nonce    string
    Value    string
    Data     string
    GasLimit string
    GasPrice string
}

func newTx(t *types.Transaction) *tx {
    from, _ := t.From()
    var to string
    if t := t.To(); t != nil {
        to = t.Hex()
    }

    return &tx{
        tx:       t,
        To:       to,
        From:     from.Hex(),
        Value:    t.Value().String(),
        Nonce:    strconv.Itoa(int(t.Nonce())),
        Data:     "0x" + common.Bytes2Hex(t.Data()),
        GasLimit: t.Gas().String(),
        GasPrice: t.GasPrice().String(),
    }
}

type ResendArgs struct {
    Tx       *tx
    GasPrice string
    GasLimit string
}

func (tx *tx) UnmarshalJSON(b []byte) (err error) {
    var fields map[string]interface{}
    if err := json.Unmarshal(b, &fields); err != nil {
        return shared.NewDecodeParamError(err.Error())
    }

    var (
        nonce            uint64
        to               common.Address
        amount           = new(big.Int).Set(common.Big0)
        gasLimit         = new(big.Int).Set(common.Big0)
        gasPrice         = new(big.Int).Set(common.Big0)
        data             []byte
        contractCreation = true
    )

    if val, found := fields["To"]; found {
        if strVal, ok := val.(string); ok && len(strVal) > 0 {
            tx.To = strVal
            to = common.HexToAddress(strVal)
            contractCreation = false
        }
    }

    if val, found := fields["From"]; found {
        if strVal, ok := val.(string); ok {
            tx.From = strVal
        }
    }

    if val, found := fields["Nonce"]; found {
        if strVal, ok := val.(string); ok {
            tx.Nonce = strVal
            if nonce, err = strconv.ParseUint(strVal, 10, 64); err != nil {
                return shared.NewDecodeParamError(fmt.Sprintf("Unable to decode tx.Nonce - %v", err))
            }
        }
    } else {
        return shared.NewDecodeParamError("tx.Nonce not found")
    }

    var parseOk bool
    if val, found := fields["Value"]; found {
        if strVal, ok := val.(string); ok {
            tx.Value = strVal
            if _, parseOk = amount.SetString(strVal, 0); !parseOk {
                return shared.NewDecodeParamError(fmt.Sprintf("Unable to decode tx.Amount - %v", err))
            }
        }
    }

    if val, found := fields["Data"]; found {
        if strVal, ok := val.(string); ok {
            tx.Data = strVal
            if strings.HasPrefix(strVal, "0x") {
                data = common.Hex2Bytes(strVal[2:])
            } else {
                data = common.Hex2Bytes(strVal)
            }
        }
    }

    if val, found := fields["GasLimit"]; found {
        if strVal, ok := val.(string); ok {
            tx.GasLimit = strVal
            if _, parseOk = gasLimit.SetString(strVal, 0); !parseOk {
                return shared.NewDecodeParamError(fmt.Sprintf("Unable to decode tx.GasLimit - %v", err))
            }
        }
    }

    if val, found := fields["GasPrice"]; found {
        if strVal, ok := val.(string); ok {
            tx.GasPrice = strVal
            if _, parseOk = gasPrice.SetString(strVal, 0); !parseOk {
                return shared.NewDecodeParamError(fmt.Sprintf("Unable to decode tx.GasPrice - %v", err))
            }
        }
    }

    if contractCreation {
        tx.tx = types.NewContractCreation(nonce, amount, gasLimit, gasPrice, data)
    } else {
        tx.tx = types.NewTransaction(nonce, to, amount, gasLimit, gasPrice, data)
    }

    return nil
}

func (args *ResendArgs) UnmarshalJSON(b []byte) (err error) {
    var obj []interface{}
    if err = json.Unmarshal(b, &obj); err != nil {
        return shared.NewDecodeParamError(err.Error())
    }

    if len(obj) < 1 {
        return shared.NewInsufficientParamsError(len(obj), 1)
    }

    data, err := json.Marshal(obj[0])
    if err != nil {
        return shared.NewDecodeParamError("Unable to parse transaction object")
    }

    trans := new(tx)
    err = json.Unmarshal(data, trans)
    if err != nil {
        return shared.NewDecodeParamError("Unable to parse transaction object")
    }

    if trans == nil || trans.tx == nil {
        return shared.NewDecodeParamError("Unable to parse transaction object")
    }

    gasLimit, gasPrice := trans.GasLimit, trans.GasPrice

    if len(obj) > 1 && obj[1] != nil {
        if gp, ok := obj[1].(string); ok {
            gasPrice = gp
        } else {
            return shared.NewInvalidTypeError("gasPrice", "not a string")
        }
    }
    if len(obj) > 2 && obj[2] != nil {
        if gl, ok := obj[2].(string); ok {
            gasLimit = gl
        } else {
            return shared.NewInvalidTypeError("gasLimit", "not a string")
        }
    }

    args.Tx = trans
    args.GasPrice = gasPrice
    args.GasLimit = gasLimit

    return nil
}