Expose a close ntfn channel to all RPC handlers.

This commit modifies the RPC server such that all handlers now receive a
channel which will be notified when a client disconnects.  This
notification can then be used to stop long-running operations early when a
client disconnects.

This capability was already present for websocket clients, but this commit
exposes it to standard HTTP clients as well.

rpcserver.go

@@ -23,6 +23,7 @@ import (
 	"github.com/conformal/btcws"
 	"github.com/conformal/fastsha256"
 	"github.com/conformal/websocket"
+	"io"
 	"io/ioutil"
 	"math/big"
 	"math/rand"
@@ -70,7 +71,7 @@ var (
 	ErrBadParamsField = errors.New("bad params field")
 )
 
-type commandHandler func(*rpcServer, btcjson.Cmd) (interface{}, error)
+type commandHandler func(*rpcServer, btcjson.Cmd, <-chan struct{}) (interface{}, error)
 
 // handlers maps RPC command strings to appropriate handler functions.
 // this is copied by init because help references rpcHandlers and thus causes
@@ -210,6 +211,8 @@ type rpcServer struct {
 	ntfnMgr         *wsNotificationManager
 	numClients      int
 	numClientsMutex sync.Mutex
+	statusLines     map[int]string
+	statusLock      sync.RWMutex
 	wg              sync.WaitGroup
 	listeners       []net.Listener
 	workState       *workState
@@ -285,6 +288,65 @@ func (s *rpcServer) Start() {
 	s.ntfnMgr.Start()
 }
 
+// httpStatusLine returns a response Status-Line (RFC 2616 Section 6.1)
+// for the given request and response status code.  This function was lifted and
+// adapted from the standard library HTTP server code since it's not exported.
+func (s *rpcServer) httpStatusLine(req *http.Request, code int) string {
+	// Fast path:
+	key := code
+	proto11 := req.ProtoAtLeast(1, 1)
+	if !proto11 {
+		key = -key
+	}
+	s.statusLock.RLock()
+	line, ok := s.statusLines[key]
+	s.statusLock.RUnlock()
+	if ok {
+		return line
+	}
+
+	// Slow path:
+	proto := "HTTP/1.0"
+	if proto11 {
+		proto = "HTTP/1.1"
+	}
+	codeStr := strconv.Itoa(code)
+	text := http.StatusText(code)
+	if text != "" {
+		line = proto + " " + codeStr + " " + text + "\r\n"
+		s.statusLock.Lock()
+		s.statusLines[key] = line
+		s.statusLock.Unlock()
+	} else {
+		text = "status code " + codeStr
+		line = proto + " " + codeStr + " " + text + "\r\n"
+	}
+
+	return line
+}
+
+// writeHTTPResponseHeaders writes the necessary response headers prior to
+// writing an HTTP body given a request to use for protocol negotiation, headers
+// to write, a status code, and a writer.
+func (s *rpcServer) writeHTTPResponseHeaders(req *http.Request, headers http.Header, code int, w io.Writer) error {
+	_, err := io.WriteString(w, s.httpStatusLine(req, code))
+	if err != nil {
+		return err
+	}
+
+	err = headers.Write(w)
+	if err != nil {
+		return err
+	}
+
+	_, err = io.WriteString(w, "\r\n")
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
 // limitConnections responds with a 503 service unavailable and returns true if
 // adding another client would exceed the maximum allow RPC clients.
 //
@@ -406,10 +468,11 @@ func newRPCServer(listenAddrs []string, s *server) (*rpcServer, error) {
 	login := cfg.RPCUser + ":" + cfg.RPCPass
 	auth := "Basic " + base64.StdEncoding.EncodeToString([]byte(login))
 	rpc := rpcServer{
-		authsha:   fastsha256.Sum256([]byte(auth)),
+		authsha:     fastsha256.Sum256([]byte(auth)),
-		server:    s,
+		server:      s,
-		workState: newWorkState(),
+		statusLines: make(map[int]string),
-		quit:      make(chan int),
+		workState:   newWorkState(),
+		quit:        make(chan int),
 	}
 	rpc.ntfnMgr = newWsNotificationManager(&rpc)
 
@@ -484,6 +547,33 @@ func jsonRPCRead(w http.ResponseWriter, r *http.Request, s *rpcServer) {
 		return
 	}
 
+	// Unfortunately, the http server doesn't provide the ability to
+	// change the read deadline for the new connection and having one breaks
+	// long polling.  However, not having a read deadline on the initial
+	// connection would mean clients can connect and idle forever.  Thus,
+	// hijack the connecton from the HTTP server, clear the read deadline,
+	// and handle writing the response manually.
+	hj, ok := w.(http.Hijacker)
+	if !ok {
+		errMsg := "webserver doesn't support hijacking"
+		rpcsLog.Warnf(errMsg)
+		errCode := http.StatusInternalServerError
+		http.Error(w, strconv.FormatInt(int64(errCode), 10)+" "+errMsg,
+			errCode)
+		return
+	}
+	conn, buf, err := hj.Hijack()
+	if err != nil {
+		rpcsLog.Warnf("Failed to hijack HTTP connection: %v", err)
+		errCode := http.StatusInternalServerError
+		http.Error(w, strconv.FormatInt(int64(errCode), 10)+" "+
+			err.Error(), errCode)
+		return
+	}
+	defer conn.Close()
+	defer buf.Flush()
+	conn.SetReadDeadline(timeZeroVal)
+
 	var reply btcjson.Reply
 	cmd, jsonErr := parseCmd(body)
 	if cmd != nil {
@@ -495,14 +585,30 @@ func jsonRPCRead(w http.ResponseWriter, r *http.Request, s *rpcServer) {
 	if jsonErr != nil {
 		reply.Error = jsonErr
 	} else {
-		reply = standardCmdReply(cmd, s)
+		// Setup a close notifier.  Since the connection is hijacked,
+		// the CloseNotifer on the ResponseWriter is not available.
+		closeChan := make(chan struct{}, 1)
+		go func() {
+			_, err := conn.Read(make([]byte, 1))
+			if err != nil {
+				close(closeChan)
+			}
+		}()
+
+		reply = standardCmdReply(cmd, s, closeChan)
 	}
 
 	rpcsLog.Tracef("reply: %v", reply)
 
-	msg, err := btcjson.MarshallAndSend(reply, w)
+	err = s.writeHTTPResponseHeaders(r, w.Header(), http.StatusOK, buf)
 	if err != nil {
-		rpcsLog.Errorf(msg)
+		rpcsLog.Error(err)
+		return
+	}
+
+	msg, err := btcjson.MarshallAndSend(reply, buf)
+	if err != nil {
+		rpcsLog.Error(err)
 		return
 	}
 	rpcsLog.Tracef(msg)
@@ -510,19 +616,19 @@ func jsonRPCRead(w http.ResponseWriter, r *http.Request, s *rpcServer) {
 
 // handleUnimplemented is a temporary handler for commands that we should
 // support but do not.
-func handleUnimplemented(s *rpcServer, cmd btcjson.Cmd) (interface{}, error) {
+func handleUnimplemented(s *rpcServer, cmd btcjson.Cmd, closeChan <-chan struct{}) (interface{}, error) {
 	return nil, btcjson.ErrUnimplemented
 }
 
 // handleAskWallet is the handler for commands that we do recognise as valid
 // but that we can not answer correctly since it involves wallet state.
 // These commands will be implemented in btcwallet.
-func handleAskWallet(s *rpcServer, cmd btcjson.Cmd) (interface{}, error) {
+func handleAskWallet(s *rpcServer, cmd btcjson.Cmd, closeChan <-chan struct{}) (interface{}, error) {
 	return nil, btcjson.ErrNoWallet
 }
 
 // handleAddNode handles addnode commands.
-func handleAddNode(s *rpcServer, cmd btcjson.Cmd) (interface{}, error) {
+func handleAddNode(s *rpcServer, cmd btcjson.Cmd, closeChan <-chan struct{}) (interface{}, error) {
 	c := cmd.(*btcjson.AddNodeCmd)
 
 	addr := normalizeAddress(c.Addr, activeNetParams.DefaultPort)
@@ -564,7 +670,7 @@ func messageToHex(msg btcwire.Message) (string, error) {
 }
 
 // handleCreateRawTransaction handles createrawtransaction commands.
-func handleCreateRawTransaction(s *rpcServer, cmd btcjson.Cmd) (interface{}, error) {
+func handleCreateRawTransaction(s *rpcServer, cmd btcjson.Cmd, closeChan <-chan struct{}) (interface{}, error) {
 	c := cmd.(*btcjson.CreateRawTransactionCmd)
 
 	// Add all transaction inputs to a new transaction after performing
@@ -650,7 +756,7 @@ func handleCreateRawTransaction(s *rpcServer, cmd btcjson.Cmd) (interface{}, err
 }
 
 // handleDebugLevel handles debuglevel commands.
-func handleDebugLevel(s *rpcServer, cmd btcjson.Cmd) (interface{}, error) {
+func handleDebugLevel(s *rpcServer, cmd btcjson.Cmd, closeChan <-chan struct{}) (interface{}, error) {
 	c := cmd.(*btcjson.DebugLevelCmd)
 
 	// Special show command to list supported subsystems.
@@ -781,7 +887,7 @@ func createTxRawResult(net *btcnet.Params, txSha string, mtx *btcwire.MsgTx,
 }
 
 // handleDecodeRawTransaction handles decoderawtransaction commands.
-func handleDecodeRawTransaction(s *rpcServer, cmd btcjson.Cmd) (interface{}, error) {
+func handleDecodeRawTransaction(s *rpcServer, cmd btcjson.Cmd, closeChan <-chan struct{}) (interface{}, error) {
 	c := cmd.(*btcjson.DecodeRawTransactionCmd)
 
 	// Deserialize the transaction.
@@ -828,7 +934,7 @@ func handleDecodeRawTransaction(s *rpcServer, cmd btcjson.Cmd) (interface{}, err
 }
 
 // handleDecodeScript handles decodescript commands.
-func handleDecodeScript(s *rpcServer, cmd btcjson.Cmd) (interface{}, error) {
+func handleDecodeScript(s *rpcServer, cmd btcjson.Cmd, closeChan <-chan struct{}) (interface{}, error) {
 	c := cmd.(*btcjson.DecodeScriptCmd)
 
 	// Convert the hex script to bytes.
@@ -876,7 +982,7 @@ func handleDecodeScript(s *rpcServer, cmd btcjson.Cmd) (interface{}, error) {
 }
 
 // handleGetAddedNodeInfo handles getaddednodeinfo commands.
-func handleGetAddedNodeInfo(s *rpcServer, cmd btcjson.Cmd) (interface{}, error) {
+func handleGetAddedNodeInfo(s *rpcServer, cmd btcjson.Cmd, closeChan <-chan struct{}) (interface{}, error) {
 	c := cmd.(*btcjson.GetAddedNodeInfoCmd)
 
 	// Retrieve a list of persistent (added) peers from the bitcoin server
@@ -959,7 +1065,7 @@ func handleGetAddedNodeInfo(s *rpcServer, cmd btcjson.Cmd) (interface{}, error)
 }
 
 // handleGetBestBlock implements the getbestblock command.
-func handleGetBestBlock(s *rpcServer, cmd btcjson.Cmd) (interface{}, error) {
+func handleGetBestBlock(s *rpcServer, cmd btcjson.Cmd, closeChan <-chan struct{}) (interface{}, error) {
 	// All other "get block" commands give either the height, the
 	// hash, or both but require the block SHA.  This gets both for
 	// the best block.
@@ -976,7 +1082,7 @@ func handleGetBestBlock(s *rpcServer, cmd btcjson.Cmd) (interface{}, error) {
 }
 
 // handleGetBestBlockHash implements the getbestblockhash command.
-func handleGetBestBlockHash(s *rpcServer, cmd btcjson.Cmd) (interface{}, error) {
+func handleGetBestBlockHash(s *rpcServer, cmd btcjson.Cmd, closeChan <-chan struct{}) (interface{}, error) {
 	sha, _, err := s.server.db.NewestSha()
 	if err != nil {
 		rpcsLog.Errorf("Error getting newest sha: %v", err)
@@ -987,7 +1093,7 @@ func handleGetBestBlockHash(s *rpcServer, cmd btcjson.Cmd) (interface{}, error)
 }
 
 // handleGetBlock implements the getblock command.
-func handleGetBlock(s *rpcServer, cmd btcjson.Cmd) (interface{}, error) {
+func handleGetBlock(s *rpcServer, cmd btcjson.Cmd, closeChan <-chan struct{}) (interface{}, error) {
 	c := cmd.(*btcjson.GetBlockCmd)
 	sha, err := btcwire.NewShaHashFromStr(c.Hash)
 	if err != nil {
@@ -1083,7 +1189,7 @@ func handleGetBlock(s *rpcServer, cmd btcjson.Cmd) (interface{}, error) {
 }
 
 // handleGetBlockCount implements the getblockcount command.
-func handleGetBlockCount(s *rpcServer, cmd btcjson.Cmd) (interface{}, error) {
+func handleGetBlockCount(s *rpcServer, cmd btcjson.Cmd, closeChan <-chan struct{}) (interface{}, error) {
 	_, maxidx, err := s.server.db.NewestSha()
 	if err != nil {
 		rpcsLog.Errorf("Error getting newest sha: %v", err)
@@ -1094,7 +1200,7 @@ func handleGetBlockCount(s *rpcServer, cmd btcjson.Cmd) (interface{}, error) {
 }
 
 // handleGetBlockHash implements the getblockhash command.
-func handleGetBlockHash(s *rpcServer, cmd btcjson.Cmd) (interface{}, error) {
+func handleGetBlockHash(s *rpcServer, cmd btcjson.Cmd, closeChan <-chan struct{}) (interface{}, error) {
 	c := cmd.(*btcjson.GetBlockHashCmd)
 	sha, err := s.server.db.FetchBlockShaByHeight(c.Index)
 	if err != nil {
@@ -1106,17 +1212,17 @@ func handleGetBlockHash(s *rpcServer, cmd btcjson.Cmd) (interface{}, error) {
 }
 
 // handleGetConnectionCount implements the getconnectioncount command.
-func handleGetConnectionCount(s *rpcServer, cmd btcjson.Cmd) (interface{}, error) {
+func handleGetConnectionCount(s *rpcServer, cmd btcjson.Cmd, closeChan <-chan struct{}) (interface{}, error) {
 	return s.server.ConnectedCount(), nil
 }
 
 // handleGetCurrentNet implements the getcurrentnet command.
-func handleGetCurrentNet(s *rpcServer, cmd btcjson.Cmd) (interface{}, error) {
+func handleGetCurrentNet(s *rpcServer, cmd btcjson.Cmd, closeChan <-chan struct{}) (interface{}, error) {
 	return s.server.netParams.Net, nil
 }
 
 // handleGetDifficulty implements the getdifficulty command.
-func handleGetDifficulty(s *rpcServer, cmd btcjson.Cmd) (interface{}, error) {
+func handleGetDifficulty(s *rpcServer, cmd btcjson.Cmd, closeChan <-chan struct{}) (interface{}, error) {
 	sha, _, err := s.server.db.NewestSha()
 	if err != nil {
 		rpcsLog.Errorf("Error getting sha: %v", err)
@@ -1131,18 +1237,18 @@ func handleGetDifficulty(s *rpcServer, cmd btcjson.Cmd) (interface{}, error) {
 }
 
 // handleGetGenerate implements the getgenerate command.
-func handleGetGenerate(s *rpcServer, cmd btcjson.Cmd) (interface{}, error) {
+func handleGetGenerate(s *rpcServer, cmd btcjson.Cmd, closeChan <-chan struct{}) (interface{}, error) {
 	return s.server.cpuMiner.IsMining(), nil
 }
 
 // handleGetHashesPerSec implements the gethashespersec command.
-func handleGetHashesPerSec(s *rpcServer, cmd btcjson.Cmd) (interface{}, error) {
+func handleGetHashesPerSec(s *rpcServer, cmd btcjson.Cmd, closeChan <-chan struct{}) (interface{}, error) {
 	return int64(s.server.cpuMiner.HashesPerSecond()), nil
 }
 
 // handleGetInfo implements the getinfo command. We only return the fields
 // that are not related to wallet functionality.
-func handleGetInfo(s *rpcServer, cmd btcjson.Cmd) (interface{}, error) {
+func handleGetInfo(s *rpcServer, cmd btcjson.Cmd, closeChan <-chan struct{}) (interface{}, error) {
 	// We require the current block height and sha.
 	sha, height, err := s.server.db.NewestSha()
 	if err != nil {
@@ -1172,7 +1278,7 @@ func handleGetInfo(s *rpcServer, cmd btcjson.Cmd) (interface{}, error) {
 
 // handleGetMiningInfo implements the getmininginfo command. We only return the
 // fields that are not related to wallet functionality.
-func handleGetMiningInfo(s *rpcServer, cmd btcjson.Cmd) (interface{}, error) {
+func handleGetMiningInfo(s *rpcServer, cmd btcjson.Cmd, closeChan <-chan struct{}) (interface{}, error) {
 	sha, height, err := s.server.db.NewestSha()
 	if err != nil {
 		rpcsLog.Errorf("Error getting sha: %v", err)
@@ -1201,7 +1307,8 @@ func handleGetMiningInfo(s *rpcServer, cmd btcjson.Cmd) (interface{}, error) {
 			Message: err.Error(),
 		}
 	}
-	networkHashesPerSecIface, err := handleGetNetworkHashPS(s, gnhpsCmd)
+	networkHashesPerSecIface, err := handleGetNetworkHashPS(s, gnhpsCmd,
+		closeChan)
 	if err != nil {
 		// This is already a btcjson.Error from the handler.
 		return nil, err
@@ -1230,7 +1337,7 @@ func handleGetMiningInfo(s *rpcServer, cmd btcjson.Cmd) (interface{}, error) {
 }
 
 // handleGetNetTotals implements the getnettotals command.
-func handleGetNetTotals(s *rpcServer, cmd btcjson.Cmd) (interface{}, error) {
+func handleGetNetTotals(s *rpcServer, cmd btcjson.Cmd, closeChan <-chan struct{}) (interface{}, error) {
 	totalBytesRecv, totalBytesSent := s.server.NetTotals()
 	reply := &btcjson.GetNetTotalsResult{
 		TotalBytesRecv: totalBytesRecv,
@@ -1241,7 +1348,7 @@ func handleGetNetTotals(s *rpcServer, cmd btcjson.Cmd) (interface{}, error) {
 }
 
 // handleGetNetworkHashPS implements the getnetworkhashps command.
-func handleGetNetworkHashPS(s *rpcServer, cmd btcjson.Cmd) (interface{}, error) {
+func handleGetNetworkHashPS(s *rpcServer, cmd btcjson.Cmd, closeChan <-chan struct{}) (interface{}, error) {
 	c := cmd.(*btcjson.GetNetworkHashPSCmd)
 
 	_, newestHeight, err := s.server.db.NewestSha()
@@ -1329,12 +1436,12 @@ func handleGetNetworkHashPS(s *rpcServer, cmd btcjson.Cmd) (interface{}, error)
 }
 
 // handleGetPeerInfo implements the getpeerinfo command.
-func handleGetPeerInfo(s *rpcServer, cmd btcjson.Cmd) (interface{}, error) {
+func handleGetPeerInfo(s *rpcServer, cmd btcjson.Cmd, closeChan <-chan struct{}) (interface{}, error) {
 	return s.server.PeerInfo(), nil
 }
 
 // handleGetRawMempool implements the getrawmempool command.
-func handleGetRawMempool(s *rpcServer, cmd btcjson.Cmd) (interface{}, error) {
+func handleGetRawMempool(s *rpcServer, cmd btcjson.Cmd, closeChan <-chan struct{}) (interface{}, error) {
 	c := cmd.(*btcjson.GetRawMempoolCmd)
 	descs := s.server.txMemPool.TxDescs()
 
@@ -1376,7 +1483,7 @@ func handleGetRawMempool(s *rpcServer, cmd btcjson.Cmd) (interface{}, error) {
 }
 
 // handleGetRawTransaction implements the getrawtransaction command.
-func handleGetRawTransaction(s *rpcServer, cmd btcjson.Cmd) (interface{}, error) {
+func handleGetRawTransaction(s *rpcServer, cmd btcjson.Cmd, closeChan <-chan struct{}) (interface{}, error) {
 	c := cmd.(*btcjson.GetRawTransactionCmd)
 
 	// Convert the provided transaction hash hex to a ShaHash.
@@ -1773,7 +1880,7 @@ func handleGetWorkSubmission(s *rpcServer, hexData string) (interface{}, error)
 }
 
 // handleGetWork implements the getwork command.
-func handleGetWork(s *rpcServer, cmd btcjson.Cmd) (interface{}, error) {
+func handleGetWork(s *rpcServer, cmd btcjson.Cmd, closeChan <-chan struct{}) (interface{}, error) {
 	c := cmd.(*btcjson.GetWorkCmd)
 
 	// Respond with an error if there are no addresses to pay the created
@@ -1836,7 +1943,7 @@ func getHelpText(cmdName string) (string, error) {
 }
 
 // handleHelp implements the help command.
-func handleHelp(s *rpcServer, cmd btcjson.Cmd) (interface{}, error) {
+func handleHelp(s *rpcServer, cmd btcjson.Cmd, closeChan <-chan struct{}) (interface{}, error) {
 	help := cmd.(*btcjson.HelpCmd)
 
 	// if no args we give a list of all known commands
@@ -1867,7 +1974,7 @@ func handleHelp(s *rpcServer, cmd btcjson.Cmd) (interface{}, error) {
 }
 
 // handlePing implements the ping command.
-func handlePing(s *rpcServer, cmd btcjson.Cmd) (interface{}, error) {
+func handlePing(s *rpcServer, cmd btcjson.Cmd, closeChan <-chan struct{}) (interface{}, error) {
 	// Ask server to ping \o_
 	nonce, err := btcwire.RandomUint64()
 	if err != nil {
@@ -1880,7 +1987,7 @@ func handlePing(s *rpcServer, cmd btcjson.Cmd) (interface{}, error) {
 }
 
 // handleSendRawTransaction implements the sendrawtransaction command.
-func handleSendRawTransaction(s *rpcServer, cmd btcjson.Cmd) (interface{}, error) {
+func handleSendRawTransaction(s *rpcServer, cmd btcjson.Cmd, closeChan <-chan struct{}) (interface{}, error) {
 	c := cmd.(*btcjson.SendRawTransactionCmd)
 	// Deserialize and send off to tx relay
 	serializedTx, err := hex.DecodeString(c.HexTx)
@@ -1929,7 +2036,7 @@ func handleSendRawTransaction(s *rpcServer, cmd btcjson.Cmd) (interface{}, error
 }
 
 // handleSetGenerate implements the setgenerate command.
-func handleSetGenerate(s *rpcServer, cmd btcjson.Cmd) (interface{}, error) {
+func handleSetGenerate(s *rpcServer, cmd btcjson.Cmd, closeChan <-chan struct{}) (interface{}, error) {
 	c := cmd.(*btcjson.SetGenerateCmd)
 
 	// Disable generation regardless of the provided generate flag if the
@@ -1961,13 +2068,13 @@ func handleSetGenerate(s *rpcServer, cmd btcjson.Cmd) (interface{}, error) {
 }
 
 // handleStop implements the stop command.
-func handleStop(s *rpcServer, cmd btcjson.Cmd) (interface{}, error) {
+func handleStop(s *rpcServer, cmd btcjson.Cmd, closeChan <-chan struct{}) (interface{}, error) {
 	s.server.Stop()
 	return "btcd stopping.", nil
 }
 
 // handleSubmitBlock implements the submitblock command.
-func handleSubmitBlock(s *rpcServer, cmd btcjson.Cmd) (interface{}, error) {
+func handleSubmitBlock(s *rpcServer, cmd btcjson.Cmd, closeChan <-chan struct{}) (interface{}, error) {
 	c := cmd.(*btcjson.SubmitBlockCmd)
 	// Deserialize and send off to block processor.
 	serializedBlock, err := hex.DecodeString(c.HexBlock)
@@ -2044,7 +2151,7 @@ func verifyChain(db btcdb.Db, level, depth int32) error {
 	return nil
 }
 
-func handleVerifyChain(s *rpcServer, cmd btcjson.Cmd) (interface{}, error) {
+func handleVerifyChain(s *rpcServer, cmd btcjson.Cmd, closeChan <-chan struct{}) (interface{}, error) {
 	c := cmd.(*btcjson.VerifyChainCmd)
 
 	err := verifyChain(s.server.db, c.CheckLevel, c.CheckDepth)
@@ -2072,7 +2179,7 @@ func parseCmd(b []byte) (btcjson.Cmd, *btcjson.Error) {
 // standardCmdReply checks that a parsed command is a standard
 // Bitcoin JSON-RPC command and runs the proper handler to reply to the
 // command.
-func standardCmdReply(cmd btcjson.Cmd, s *rpcServer) (reply btcjson.Reply) {
+func standardCmdReply(cmd btcjson.Cmd, s *rpcServer, closeChan <-chan struct{}) (reply btcjson.Reply) {
 	id := cmd.Id()
 	reply.Id = &id
 
@@ -2094,7 +2201,7 @@ func standardCmdReply(cmd btcjson.Cmd, s *rpcServer) (reply btcjson.Reply) {
 	return reply
 handled:
 
-	result, err := handler(s, cmd)
+	result, err := handler(s, cmd, closeChan)
 	if err != nil {
 		jsonErr, ok := err.(btcjson.Error)
 		if !ok {

rpcwebsocket.go

@@ -1015,7 +1015,7 @@ func (c *wsClient) handleMessage(msg []byte) {
 	if !ok {
 		// No websocket-specific handler so handle like a legacy
 		// RPC connection.
-		response := standardCmdReply(cmd, c.server)
+		response := standardCmdReply(cmd, c.server, nil)
 		reply, err := json.Marshal(response)
 		if err != nil {
 			rpcsLog.Errorf("Failed to marshal reply for <%s> "+