rpc, xeth: fix #881, gracefully handle offline whisper

rpc/api.go

@@ -439,10 +439,18 @@ func (api *EthereumApi) GetRequestReply(req *RpcRequest, reply *interface{}) err
 		*reply = newHexData(res)
 
 	case "shh_version":
+		// Short circuit if whisper is not running
+		if api.xeth().Whisper() == nil {
+			return NewNotAvailableError(req.Method, "whisper offline")
+		}
 		// Retrieves the currently running whisper protocol version
 		*reply = api.xeth().WhisperVersion()
 
 	case "shh_post":
+		// Short circuit if whisper is not running
+		if api.xeth().Whisper() == nil {
+			return NewNotAvailableError(req.Method, "whisper offline")
+		}
 		// Injects a new message into the whisper network
 		args := new(WhisperMessageArgs)
 		if err := json.Unmarshal(req.Params, &args); err != nil {
@@ -455,10 +463,18 @@ func (api *EthereumApi) GetRequestReply(req *RpcRequest, reply *interface{}) err
 		*reply = true
 
 	case "shh_newIdentity":
+		// Short circuit if whisper is not running
+		if api.xeth().Whisper() == nil {
+			return NewNotAvailableError(req.Method, "whisper offline")
+		}
 		// Creates a new whisper identity to use for sending/receiving messages
 		*reply = api.xeth().Whisper().NewIdentity()
 
 	case "shh_hasIdentity":
+		// Short circuit if whisper is not running
+		if api.xeth().Whisper() == nil {
+			return NewNotAvailableError(req.Method, "whisper offline")
+		}
 		// Checks if an identity if owned or not
 		args := new(WhisperIdentityArgs)
 		if err := json.Unmarshal(req.Params, &args); err != nil {
@@ -467,6 +483,10 @@ func (api *EthereumApi) GetRequestReply(req *RpcRequest, reply *interface{}) err
 		*reply = api.xeth().Whisper().HasIdentity(args.Identity)
 
 	case "shh_newFilter":
+		// Short circuit if whisper is not running
+		if api.xeth().Whisper() == nil {
+			return NewNotAvailableError(req.Method, "whisper offline")
+		}
 		// Create a new filter to watch and match messages with
 		args := new(WhisperFilterArgs)
 		if err := json.Unmarshal(req.Params, &args); err != nil {
@@ -476,6 +496,10 @@ func (api *EthereumApi) GetRequestReply(req *RpcRequest, reply *interface{}) err
 		*reply = newHexNum(big.NewInt(int64(id)).Bytes())
 
 	case "shh_uninstallFilter":
+		// Short circuit if whisper is not running
+		if api.xeth().Whisper() == nil {
+			return NewNotAvailableError(req.Method, "whisper offline")
+		}
 		// Remove an existing filter watching messages
 		args := new(FilterIdArgs)
 		if err := json.Unmarshal(req.Params, &args); err != nil {
@@ -484,6 +508,10 @@ func (api *EthereumApi) GetRequestReply(req *RpcRequest, reply *interface{}) err
 		*reply = api.xeth().UninstallWhisperFilter(args.Id)
 
 	case "shh_getFilterChanges":
+		// Short circuit if whisper is not running
+		if api.xeth().Whisper() == nil {
+			return NewNotAvailableError(req.Method, "whisper offline")
+		}
 		// Retrieve all the new messages arrived since the last request
 		args := new(FilterIdArgs)
 		if err := json.Unmarshal(req.Params, &args); err != nil {
@@ -492,12 +520,17 @@ func (api *EthereumApi) GetRequestReply(req *RpcRequest, reply *interface{}) err
 		*reply = api.xeth().WhisperMessagesChanged(args.Id)
 
 	case "shh_getMessages":
+		// Short circuit if whisper is not running
+		if api.xeth().Whisper() == nil {
+			return NewNotAvailableError(req.Method, "whisper offline")
+		}
 		// Retrieve all the cached messages matching a specific, existing filter
 		args := new(FilterIdArgs)
 		if err := json.Unmarshal(req.Params, &args); err != nil {
 			return err
 		}
 		*reply = api.xeth().WhisperMessages(args.Id)
+
 	case "eth_hashrate":
 		*reply = newHexNum(api.xeth().HashRate())
 

rpc/http.go

@@ -116,7 +116,7 @@ func RpcResponse(api *EthereumApi, request *RpcRequest) *interface{} {
 	switch reserr.(type) {
 	case nil:
 		response = &RpcSuccessResponse{Jsonrpc: jsonrpcver, Id: request.Id, Result: reply}
-	case *NotImplementedError:
+	case *NotImplementedError, *NotAvailableError:
 		jsonerr := &RpcErrorObject{-32601, reserr.Error()}
 		response = &RpcErrorResponse{Jsonrpc: jsonrpcver, Id: request.Id, Error: jsonerr}
 	case *DecodeParamError, *InsufficientParamsError, *ValidationError, *InvalidTypeError:

rpc/types.go

@@ -209,6 +209,22 @@ func NewNotImplementedError(method string) *NotImplementedError {
 	}
 }
 
+type NotAvailableError struct {
+	Method string
+	Reason string
+}
+
+func (e *NotAvailableError) Error() string {
+	return fmt.Sprintf("%s method not available: %s", e.Method, e.Reason)
+}
+
+func NewNotAvailableError(method string, reason string) *NotAvailableError {
+	return &NotAvailableError{
+		Method: method,
+		Reason: reason,
+	}
+}
+
 type DecodeParamError struct {
 	err string
 }

xeth/xeth.go

@@ -79,7 +79,6 @@ func New(eth *eth.Ethereum, frontend Frontend) *XEth {
 	xeth := &XEth{
 		backend:          eth,
 		frontend:         frontend,
-		whisper:          NewWhisper(eth.Whisper()),
 		quit:             make(chan struct{}),
 		filterManager:    filter.NewFilterManager(eth.EventMux()),
 		logQueue:         make(map[int]*logQueue),
@@ -88,6 +87,9 @@ func New(eth *eth.Ethereum, frontend Frontend) *XEth {
 		messages:         make(map[int]*whisperFilter),
 		agent:            miner.NewRemoteAgent(),
 	}
+	if eth.Whisper() != nil {
+		xeth.whisper = NewWhisper(eth.Whisper())
+	}
 	eth.Miner().Register(xeth.agent)
 	if frontend == nil {
 		xeth.frontend = dummyFrontend{}