rpcclient: Add getblockfilter JSON-RPC client command

btcjson/chainsvrcmds.go

@@ -163,6 +163,33 @@ func NewGetBlockCountCmd() *GetBlockCountCmd {
 	return &GetBlockCountCmd{}
 }
 
+// FilterTypeName defines the type used in the getblockfilter JSON-RPC command for the
+// filter type field.
+type FilterTypeName string
+
+const (
+	// FilterTypeBasic is the basic filter type defined in BIP0158.
+	FilterTypeBasic FilterTypeName = "basic"
+)
+
+// GetBlockFilterCmd defines the getblockfilter JSON-RPC command.
+type GetBlockFilterCmd struct {
+	BlockHash  string          // The hash of the block
+	FilterType *FilterTypeName // The type name of the filter, default=basic
+}
+
+// NewGetBlockFilterCmd returns a new instance which can be used to issue a
+// getblockfilter JSON-RPC command.
+//
+// The parameters which are pointers indicate they are optional.  Passing nil
+// for optional parameters will use the default value.
+func NewGetBlockFilterCmd(blockHash string, filterType *FilterTypeName) *GetBlockFilterCmd {
+	return &GetBlockFilterCmd{
+		BlockHash:  blockHash,
+		FilterType: filterType,
+	}
+}
+
 // GetBlockHashCmd defines the getblockhash JSON-RPC command.
 type GetBlockHashCmd struct {
 	Index int64
@@ -840,6 +867,7 @@ func init() {
 	MustRegisterCmd("getblock", (*GetBlockCmd)(nil), flags)
 	MustRegisterCmd("getblockchaininfo", (*GetBlockChainInfoCmd)(nil), flags)
 	MustRegisterCmd("getblockcount", (*GetBlockCountCmd)(nil), flags)
+	MustRegisterCmd("getblockfilter", (*GetBlockFilterCmd)(nil), flags)
 	MustRegisterCmd("getblockhash", (*GetBlockHashCmd)(nil), flags)
 	MustRegisterCmd("getblockheader", (*GetBlockHeaderCmd)(nil), flags)
 	MustRegisterCmd("getblockstats", (*GetBlockStatsCmd)(nil), flags)

btcjson/chainsvrcmds_test.go

@@ -203,6 +203,28 @@ func TestChainSvrCmds(t *testing.T) {
 			marshalled:   `{"jsonrpc":"1.0","method":"getblockcount","params":[],"id":1}`,
 			unmarshalled: &btcjson.GetBlockCountCmd{},
 		},
+		{
+			name: "getblockfilter",
+			newCmd: func() (interface{}, error) {
+				return btcjson.NewCmd("getblockfilter", "0000afaf")
+			},
+			staticCmd: func() interface{} {
+				return btcjson.NewGetBlockFilterCmd("0000afaf", nil)
+			},
+			marshalled:   `{"jsonrpc":"1.0","method":"getblockfilter","params":["0000afaf"],"id":1}`,
+			unmarshalled: &btcjson.GetBlockFilterCmd{"0000afaf", nil},
+		},
+		{
+			name: "getblockfilter optional filtertype",
+			newCmd: func() (interface{}, error) {
+				return btcjson.NewCmd("getblockfilter", "0000afaf", "basic")
+			},
+			staticCmd: func() interface{} {
+				return btcjson.NewGetBlockFilterCmd("0000afaf", btcjson.NewFilterTypeName(btcjson.FilterTypeBasic))
+			},
+			marshalled:   `{"jsonrpc":"1.0","method":"getblockfilter","params":["0000afaf","basic"],"id":1}`,
+			unmarshalled: &btcjson.GetBlockFilterCmd{"0000afaf", btcjson.NewFilterTypeName(btcjson.FilterTypeBasic)},
+		},
 		{
 			name: "getblockhash",
 			newCmd: func() (interface{}, error) {

btcjson/chainsvrresults.go

@@ -207,6 +207,13 @@ type GetBlockChainInfoResult struct {
 	*UnifiedSoftForks
 }
 
+// GetBlockFilterResult models the data returned from the getblockfilter
+// command.
+type GetBlockFilterResult struct {
+	Filter string `json:"filter"` // the hex-encoded filter data
+	Header string `json:"header"` // the hex-encoded filter header
+}
+
 // GetBlockTemplateResultTx models the transactions field of the
 // getblocktemplate command.
 type GetBlockTemplateResultTx struct {

btcjson/helpers.go

@@ -75,3 +75,11 @@ func String(v string) *string {
 	*p = v
 	return p
 }
+
+// NewFilterTypeName is a helper routine that allocates a new FilterTypeName value to store v and
+// returns a pointer to it.  This is useful when assigning optional parameters.
+func NewFilterTypeName(v FilterTypeName) *FilterTypeName {
+	p := new(FilterTypeName)
+	*p = v
+	return p
+}

rpcclient/chain.go

@@ -362,6 +362,44 @@ func (c *Client) GetBlockChainInfo() (*btcjson.GetBlockChainInfoResult, error) {
 	return c.GetBlockChainInfoAsync().Receive()
 }
 
+// FutureGetBlockFilterResult is a future promise to deliver the result of a
+// GetBlockFilterAsync RPC invocation (or an applicable error).
+type FutureGetBlockFilterResult chan *response
+
+// Receive waits for the response promised by the future and returns block filter
+// result provided by the server.
+func (r FutureGetBlockFilterResult) Receive() (*btcjson.GetBlockFilterResult, error) {
+	res, err := receiveFuture(r)
+	if err != nil {
+		return nil, err
+	}
+
+	var blockFilter btcjson.GetBlockFilterResult
+	err = json.Unmarshal(res, &blockFilter)
+	if err != nil {
+		return nil, err
+	}
+
+	return &blockFilter, nil
+}
+
+// GetBlockFilterAsync 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 GetBlockFilter for the blocking version and more details.
+func (c *Client) GetBlockFilterAsync(blockHash chainhash.Hash, filterType *btcjson.FilterTypeName) FutureGetBlockFilterResult {
+	hash := blockHash.String()
+
+	cmd := btcjson.NewGetBlockFilterCmd(hash, filterType)
+	return c.sendCmd(cmd)
+}
+
+// GetBlockFilter retrieves a BIP0157 content filter for a particular block.
+func (c *Client) GetBlockFilter(blockHash chainhash.Hash, filterType *btcjson.FilterTypeName) (*btcjson.GetBlockFilterResult, error) {
+	return c.GetBlockFilterAsync(blockHash, filterType).Receive()
+}
+
 // FutureGetBlockHashResult is a future promise to deliver the result of a
 // GetBlockHashAsync RPC invocation (or an applicable error).
 type FutureGetBlockHashResult chan *response