cli: support voting

Closes #1206.

cli/wallet/wallet.go

@@ -13,7 +13,11 @@ import (
 	"github.com/nspcc-dev/neo-go/cli/options"
 	"github.com/nspcc-dev/neo-go/pkg/crypto/keys"
 	"github.com/nspcc-dev/neo-go/pkg/encoding/address"
+	"github.com/nspcc-dev/neo-go/pkg/io"
+	"github.com/nspcc-dev/neo-go/pkg/rpc/client"
 	"github.com/nspcc-dev/neo-go/pkg/util"
+	"github.com/nspcc-dev/neo-go/pkg/vm/emit"
+	"github.com/nspcc-dev/neo-go/pkg/vm/opcode"
 	"github.com/nspcc-dev/neo-go/pkg/wallet"
 	"github.com/urfave/cli"
 	"golang.org/x/crypto/ssh/terminal"
@@ -186,6 +190,24 @@ func NewCommands() []cli.Command {
 				Usage:       "work with NEP5 contracts",
 				Subcommands: newNEP5Commands(),
 			},
+			{
+				Name:      "vote",
+				Usage:     "vote for a validator",
+				UsageText: "vote -w <path> -r <rpc> [-t <timeout>] [-g gas] -a <addr> -k <public key>",
+				Action:    handleVote,
+				Flags: append([]cli.Flag{
+					walletPathFlag,
+					gasFlag,
+					flags.AddressFlag{
+						Name:  "addr, a",
+						Usage: "Address to vote from",
+					},
+					cli.StringFlag{
+						Name:  "key, k",
+						Usage: "Public key of candidate to vote for",
+					},
+				}, options.RPC...),
+			},
 		},
 	}}
 }
@@ -513,6 +535,69 @@ func createWallet(ctx *cli.Context) error {
 	return nil
 }
 
+func handleVote(ctx *cli.Context) error {
+	wall, err := openWallet(ctx.String("wallet"))
+	if err != nil {
+		return cli.NewExitError(err, 1)
+	}
+
+	addrFlag := ctx.Generic("addr").(*flags.Address)
+	addr := addrFlag.Uint160()
+	acc := wall.GetAccount(addr)
+	if acc == nil {
+		return cli.NewExitError(fmt.Errorf("can't find account for the address: %s", addrFlag), 1)
+	}
+
+	var pub *keys.PublicKey
+	pubStr := ctx.String("key")
+	if pubStr != "" {
+		pub, err = keys.NewPublicKeyFromString(pubStr)
+		if err != nil {
+			return cli.NewExitError(fmt.Errorf("invalid public key: '%s'", pubStr), 1)
+		}
+	}
+
+	gctx, cancel := options.GetTimeoutContext(ctx)
+	defer cancel()
+
+	c, err := options.GetRPCClient(gctx, ctx)
+	if err != nil {
+		return err
+	}
+
+	var pubArg interface{}
+	if pub != nil {
+		pubArg = pub.Bytes()
+	}
+
+	gas := flags.Fixed8FromContext(ctx, "gas")
+	w := io.NewBufBinWriter()
+	emit.AppCallWithOperationAndArgs(w.BinWriter, client.NeoContractHash, "vote", addr.BytesBE(), pubArg)
+	emit.Opcode(w.BinWriter, opcode.ASSERT)
+
+	tx, err := c.CreateTxFromScript(w.Bytes(), acc, int64(gas))
+	if err != nil {
+		return cli.NewExitError(err, 1)
+	}
+
+	if pass, err := readPassword("Password > "); err != nil {
+		return cli.NewExitError(err, 1)
+	} else if err := acc.Decrypt(pass); err != nil {
+		return cli.NewExitError(err, 1)
+	}
+
+	if err = acc.SignTx(tx); err != nil {
+		return cli.NewExitError(fmt.Errorf("can't sign tx: %v", err), 1)
+	}
+
+	res, err := c.SendRawTransaction(tx)
+	if err != nil {
+		return cli.NewExitError(err, 1)
+	}
+	fmt.Println(res.StringLE())
+	return nil
+}
+
 func readAccountInfo() (string, string, error) {
 	buf := bufio.NewReader(os.Stdin)
 	fmt.Print("Enter the name of the account > ")

pkg/rpc/client/nep5.go

@@ -131,8 +131,15 @@ func (c *Client) CreateNEP5MultiTransferTx(acc *wallet.Account, gas int64, recep
 			recepients[i].Address, recepients[i].Amount)
 		emit.Opcode(w.BinWriter, opcode.ASSERT)
 	}
+	return c.CreateTxFromScript(w.Bytes(), acc, gas)
+}
 
-	script := w.Bytes()
+// CreateTxFromScript creates transaction and properly sets cosigners and NetworkFee.
+func (c *Client) CreateTxFromScript(script []byte, acc *wallet.Account, gas int64) (*transaction.Transaction, error) {
+	from, err := address.StringToUint160(acc.Address)
+	if err != nil {
+		return nil, fmt.Errorf("bad account address: %v", err)
+	}
 	result, err := c.InvokeScript(script, []transaction.Signer{
 		{
 			Account: from,