Add estimatesmartfee RPC call

btcjson/chainsvrresults.go

@@ -584,3 +584,11 @@ type ValidateAddressChainResult struct {
 	IsValid bool   `json:"isvalid"`
 	Address string `json:"address,omitempty"`
 }
+
+// EstimateSmartFeeResult models the data returned buy the chain server
+// estimatesmartfee command
+type EstimateSmartFeeResult struct {
+	FeeRate *float64 `json:"feerate,omitempty"`
+	Errors  []string `json:"errors,omitempty"`
+	Blocks  int64    `json:"blocks"`
+}

btcjson/walletsvrcmds.go

@@ -81,6 +81,30 @@ func NewEncryptWalletCmd(passphrase string) *EncryptWalletCmd {
 	}
 }
 
+// EstimateSmartFeeMode defines the different fee estimation modes available
+// for the estimatesmartfee JSON-RPC command.
+type EstimateSmartFeeMode string
+
+var (
+	EstimateModeUnset        EstimateSmartFeeMode = "UNSET"
+	EstimateModeEconomical   EstimateSmartFeeMode = "ECONOMICAL"
+	EstimateModeConservative EstimateSmartFeeMode = "CONSERVATIVE"
+)
+
+// EstimateSmartFeeCmd defines the estimatesmartfee JSON-RPC command.
+type EstimateSmartFeeCmd struct {
+	ConfTarget   int64
+	EstimateMode *EstimateSmartFeeMode `jsonrpcdefault:"\"CONSERVATIVE\""`
+}
+
+// NewEstimateSmartFeeCmd returns a new instance which can be used to issue a
+// estimatesmartfee JSON-RPC command.
+func NewEstimateSmartFeeCmd(confTarget int64, mode *EstimateSmartFeeMode) *EstimateSmartFeeCmd {
+	return &EstimateSmartFeeCmd{
+		ConfTarget: confTarget, EstimateMode: mode,
+	}
+}
+
 // EstimateFeeCmd defines the estimatefee JSON-RPC command.
 type EstimateFeeCmd struct {
 	NumBlocks int64
@@ -662,6 +686,7 @@ func init() {
 	MustRegisterCmd("createmultisig", (*CreateMultisigCmd)(nil), flags)
 	MustRegisterCmd("dumpprivkey", (*DumpPrivKeyCmd)(nil), flags)
 	MustRegisterCmd("encryptwallet", (*EncryptWalletCmd)(nil), flags)
+	MustRegisterCmd("estimatesmartfee", (*EstimateSmartFeeCmd)(nil), flags)
 	MustRegisterCmd("estimatefee", (*EstimateFeeCmd)(nil), flags)
 	MustRegisterCmd("estimatepriority", (*EstimatePriorityCmd)(nil), flags)
 	MustRegisterCmd("getaccount", (*GetAccountCmd)(nil), flags)

btcjson/walletsvrcmds_test.go

@@ -128,6 +128,34 @@ func TestWalletSvrCmds(t *testing.T) {
 				NumBlocks: 6,
 			},
 		},
+		{
+			name: "estimatesmartfee - no mode",
+			newCmd: func() (interface{}, error) {
+				return btcjson.NewCmd("estimatesmartfee", 6)
+			},
+			staticCmd: func() interface{} {
+				return btcjson.NewEstimateSmartFeeCmd(6, nil)
+			},
+			marshalled: `{"jsonrpc":"1.0","method":"estimatesmartfee","params":[6],"id":1}`,
+			unmarshalled: &btcjson.EstimateSmartFeeCmd{
+				ConfTarget:   6,
+				EstimateMode: &btcjson.EstimateModeConservative,
+			},
+		},
+		{
+			name: "estimatesmartfee - economical mode",
+			newCmd: func() (interface{}, error) {
+				return btcjson.NewCmd("estimatesmartfee", 6, btcjson.EstimateModeEconomical)
+			},
+			staticCmd: func() interface{} {
+				return btcjson.NewEstimateSmartFeeCmd(6, &btcjson.EstimateModeEconomical)
+			},
+			marshalled: `{"jsonrpc":"1.0","method":"estimatesmartfee","params":[6,"ECONOMICAL"],"id":1}`,
+			unmarshalled: &btcjson.EstimateSmartFeeCmd{
+				ConfTarget:   6,
+				EstimateMode: &btcjson.EstimateModeEconomical,
+			},
+		},
 		{
 			name: "estimatepriority",
 			newCmd: func() (interface{}, error) {

rpcclient/chain.go

@@ -649,6 +649,41 @@ func (c *Client) EstimateFee(numBlocks int64) (float64, error) {
 	return c.EstimateFeeAsync(numBlocks).Receive()
 }
 
+// FutureEstimateFeeResult is a future promise to deliver the result of a
+// EstimateSmartFeeAsync RPC invocation (or an applicable error).
+type FutureEstimateSmartFeeResult chan *response
+
+// Receive waits for the response promised by the future and returns the
+// estimated fee.
+func (r FutureEstimateSmartFeeResult) Receive() (*btcjson.EstimateSmartFeeResult, error) {
+	res, err := receiveFuture(r)
+	if err != nil {
+		return nil, err
+	}
+
+	var verified btcjson.EstimateSmartFeeResult
+	err = json.Unmarshal(res, &verified)
+	if err != nil {
+		return nil, err
+	}
+	return &verified, nil
+}
+
+// EstimateSmartFeeAsync returns an instance of a type that can be used to get the
+// result of the RPC at some future time by invoking the Receive function on the
+// returned instance.
+//
+// See EstimateSmartFee for the blocking version and more details.
+func (c *Client) EstimateSmartFeeAsync(confTarget int64, mode *btcjson.EstimateSmartFeeMode) FutureEstimateSmartFeeResult {
+	cmd := btcjson.NewEstimateSmartFeeCmd(confTarget, mode)
+	return c.sendCmd(cmd)
+}
+
+// EstimateSmartFee requests the server to estimate a fee level based on the given parameters.
+func (c *Client) EstimateSmartFee(confTarget int64, mode *btcjson.EstimateSmartFeeMode) (*btcjson.EstimateSmartFeeResult, error) {
+	return c.EstimateSmartFeeAsync(confTarget, mode).Receive()
+}
+
 // FutureVerifyChainResult is a future promise to deliver the result of a
 // VerifyChainAsync, VerifyChainLevelAsyncRPC, or VerifyChainBlocksAsync
 // invocation (or an applicable error).