frontend: implement SendTransaction

frontend/rpc_client.go

@@ -0,0 +1,37 @@
+package frontend
+
+import (
+	"net"
+
+	"github.com/btcsuite/btcd/rpcclient"
+	"github.com/pkg/errors"
+	ini "gopkg.in/ini.v1"
+)
+
+func NewZRPCFromConf(confPath string) (*rpcclient.Client, error) {
+	cfg, err := ini.Load(confPath)
+	if err != nil {
+		return nil, errors.Wrap(err, "failed to read config file")
+	}
+
+	rpcaddr := cfg.Section("").Key("rpcbind").String()
+	rpcport := cfg.Section("").Key("rpcport").String()
+	username := cfg.Section("").Key("rpcuser").String()
+	password := cfg.Section("").Key("rpcpassword").String()
+
+	return NewZRPCFromCreds(net.JoinHostPort(rpcaddr, rpcport), username, password)
+}
+
+func NewZRPCFromCreds(addr, username, password string) (*rpcclient.Client, error) {
+	// Connect to local zcash RPC server using HTTP POST mode.
+	connCfg := &rpcclient.ConnConfig{
+		Host:         addr,
+		User:         username,
+		Pass:         password,
+		HTTPPostMode: true, // Zcash only supports HTTP POST mode
+		DisableTLS:   true, // Zcash does not provide TLS by default
+	}
+	// Notice the notification parameter is nil since notifications are
+	// not supported in HTTP POST mode.
+	return rpcclient.New(connCfg, nil)
+}