rpc/api, xeth: added signTransaction method

SignTransaction creates a transaction but does submit it to the
network. SignTransaction returns a structure which includes the
transaction object details as well as the RLP encoded transaction that
could possibly be submitted by the SendRawTransaction method.

rpc/api/eth.go

@@ -26,6 +26,7 @@ import (
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/common/natspec"
 	"github.com/ethereum/go-ethereum/eth"
+	"github.com/ethereum/go-ethereum/rlp"
 	"github.com/ethereum/go-ethereum/rpc/codec"
 	"github.com/ethereum/go-ethereum/rpc/shared"
 	"github.com/ethereum/go-ethereum/xeth"
@@ -70,8 +71,10 @@ var (
 		"eth_getCode":                             (*ethApi).GetData,
 		"eth_getNatSpec":                          (*ethApi).GetNatSpec,
 		"eth_sign":                                (*ethApi).Sign,
-		"eth_sendRawTransaction":                  (*ethApi).SendRawTransaction,
+		"eth_sendRawTransaction":                  (*ethApi).SubmitTransaction,
+		"eth_submitTransaction":                   (*ethApi).SubmitTransaction,
 		"eth_sendTransaction":                     (*ethApi).SendTransaction,
+		"eth_signTransaction":                     (*ethApi).SignTransaction,
 		"eth_transact":                            (*ethApi).SendTransaction,
 		"eth_estimateGas":                         (*ethApi).EstimateGas,
 		"eth_call":                                (*ethApi).Call,
@@ -285,7 +288,7 @@ func (self *ethApi) Sign(req *shared.Request) (interface{}, error) {
 	return v, nil
 }
 
-func (self *ethApi) SendRawTransaction(req *shared.Request) (interface{}, error) {
+func (self *ethApi) SubmitTransaction(req *shared.Request) (interface{}, error) {
 	args := new(NewDataArgs)
 	if err := self.codec.Decode(req.Params, &args); err != nil {
 		return nil, shared.NewDecodeParamError(err.Error())
@@ -298,6 +301,45 @@ func (self *ethApi) SendRawTransaction(req *shared.Request) (interface{}, error)
 	return v, nil
 }
 
+// JsonTransaction is returned as response by the JSON RPC. It contains the
+// signed RLP encoded transaction as Raw and the signed transaction object as Tx.
+type JsonTransaction struct {
+	Raw string `json:"raw"`
+	Tx  *tx    `json:"tx"`
+}
+
+func (self *ethApi) SignTransaction(req *shared.Request) (interface{}, error) {
+	args := new(NewTxArgs)
+	if err := self.codec.Decode(req.Params, &args); err != nil {
+		return nil, shared.NewDecodeParamError(err.Error())
+	}
+
+	// nonce may be nil ("guess" mode)
+	var nonce string
+	if args.Nonce != nil {
+		nonce = args.Nonce.String()
+	}
+
+	var gas, price string
+	if args.Gas != nil {
+		gas = args.Gas.String()
+	}
+	if args.GasPrice != nil {
+		price = args.GasPrice.String()
+	}
+	tx, err := self.xeth.SignTransaction(args.From, args.To, nonce, args.Value.String(), gas, price, args.Data)
+	if err != nil {
+		return nil, err
+	}
+
+	data, err := rlp.EncodeToBytes(tx)
+	if err != nil {
+		return nil, err
+	}
+
+	return JsonTransaction{"0x" + common.Bytes2Hex(data), newTx(tx)}, nil
+}
+
 func (self *ethApi) SendTransaction(req *shared.Request) (interface{}, error) {
 	args := new(NewTxArgs)
 	if err := self.codec.Decode(req.Params, &args); err != nil {

rpc/api/eth_js.go

@@ -41,6 +41,18 @@ web3._extend({
 			call: 'eth_getNatSpec',
 			params: 1,
 			inputFormatter: [web3._extend.formatters.inputTransactionFormatter]
+		}),
+		new web3._extend.Method({
+			name: 'signTransaction',
+			call: 'eth_signTransaction',
+			params: 1,
+			inputFormatter: [web3._extend.formatters.inputTransactionFormatter]
+		}),
+		new web3._extend.Method({
+			name: 'submitTransaction',
+			call: 'eth_submitTransaction',
+			params: 1,
+			inputFormatter: [web3._extend.formatters.inputTransactionFormatter]
 		})
 	],
 	properties:

xeth/xeth.go

@@ -912,6 +912,60 @@ func (self *XEth) Frontend() Frontend {
 	return self.frontend
 }
 
+func (self *XEth) SignTransaction(fromStr, toStr, nonceStr, valueStr, gasStr, gasPriceStr, codeStr string) (*types.Transaction, error) {
+	if len(toStr) > 0 && toStr != "0x" && !isAddress(toStr) {
+		return nil, errors.New("Invalid address")
+	}
+
+	var (
+		from             = common.HexToAddress(fromStr)
+		to               = common.HexToAddress(toStr)
+		value            = common.Big(valueStr)
+		gas              *big.Int
+		price            *big.Int
+		data             []byte
+		contractCreation bool
+	)
+
+	if len(gasStr) == 0 {
+		gas = DefaultGas()
+	} else {
+		gas = common.Big(gasStr)
+	}
+
+	if len(gasPriceStr) == 0 {
+		price = self.DefaultGasPrice()
+	} else {
+		price = common.Big(gasPriceStr)
+	}
+
+	data = common.FromHex(codeStr)
+	if len(toStr) == 0 {
+		contractCreation = true
+	}
+
+	var nonce uint64
+	if len(nonceStr) != 0 {
+		nonce = common.Big(nonceStr).Uint64()
+	} else {
+		state := self.backend.TxPool().State()
+		nonce = state.GetNonce(from)
+	}
+	var tx *types.Transaction
+	if contractCreation {
+		tx = types.NewContractCreation(nonce, value, gas, price, data)
+	} else {
+		tx = types.NewTransaction(nonce, to, value, gas, price, data)
+	}
+
+	signed, err := self.sign(tx, from, false)
+	if err != nil {
+		return nil, err
+	}
+
+	return signed, nil
+}
+
 func (self *XEth) Transact(fromStr, toStr, nonceStr, valueStr, gasStr, gasPriceStr, codeStr string) (string, error) {
 
 	// this minimalistic recoding is enough (works for natspec.js)