Merge pull request #2035 from bas-vk/rcp-v2-rebase

rpc: new RPC implementation with pub/sub support

1 files changed, 343 insertions, 0 deletions

diff --git a/rpc/v2/json.go b/rpc/v2/json.go
new file mode 100644
index 000000000..9208e2d37
--- /dev/null
+++ b/rpc/v2/json.go
@@ -0,0 +1,343 @@
+// Copyright 2015 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package v2
+
+import (
+	"encoding/json"
+	"fmt"
+	"io"
+	"reflect"
+	"strings"
+	"sync/atomic"
+
+	"github.com/ethereum/go-ethereum/logger"
+	"github.com/ethereum/go-ethereum/logger/glog"
+)
+
+const (
+	jsonRPCVersion         = "2.0"
+	serviceMethodSeparator = "_"
+	subscribeMethod        = "eth_subscribe"
+	unsubscribeMethod      = "eth_unsubscribe"
+	notificationMethod     = "eth_subscription"
+)
+
+// JSON-RPC request
+type jsonRequest struct {
+	Method  string          `json:"method"`
+	Version string          `json:"jsonrpc"`
+	Id      *int64          `json:"id,omitempty"`
+	Payload json.RawMessage `json:"params"`
+}
+
+// JSON-RPC response
+type jsonSuccessResponse struct {
+	Version string      `json:"jsonrpc"`
+	Id      int64       `json:"id"`
+	Result  interface{} `json:"result,omitempty"`
+}
+
+// JSON-RPC error object
+type jsonError struct {
+	Code    int         `json:"code"`
+	Message string      `json:"message"`
+	Data    interface{} `json:"data,omitempty"`
+}
+
+// JSON-RPC error response
+type jsonErrResponse struct {
+	Version string    `json:"jsonrpc"`
+	Id      *int64    `json:"id,omitempty"`
+	Error   jsonError `json:"error"`
+}
+
+// JSON-RPC notification payload
+type jsonSubscription struct {
+	Subscription string      `json:"subscription"`
+	Result       interface{} `json:"result,omitempty"`
+}
+
+// JSON-RPC notification
+type jsonNotification struct {
+	Version string           `json:"jsonrpc"`
+	Method  string           `json:"method"`
+	Params  jsonSubscription `json:"params"`
+}
+
+// jsonCodec reads and writes JSON-RPC messages to the underlying connection. It also has support for parsing arguments
+// and serializing (result) objects.
+type jsonCodec struct {
+	closed   chan interface{}
+	isClosed int32
+	d        *json.Decoder
+	e        *json.Encoder
+	req      jsonRequest
+	rw       io.ReadWriteCloser
+}
+
+// NewJSONCodec creates a new RPC server codec with support for JSON-RPC 2.0
+func NewJSONCodec(rwc io.ReadWriteCloser) ServerCodec {
+	d := json.NewDecoder(rwc)
+	d.UseNumber()
+	return &jsonCodec{closed: make(chan interface{}), d: d, e: json.NewEncoder(rwc), rw: rwc, isClosed: 0}
+}
+
+// isBatch returns true when the first non-whitespace characters is '['
+func isBatch(msg json.RawMessage) bool {
+	for _, c := range msg {
+		// skip insignificant whitespace (http://www.ietf.org/rfc/rfc4627.txt)
+		if c == 0x20 || c == 0x09 || c == 0x0a || c == 0x0d {
+			continue
+		}
+		return c == '['
+	}
+	return false
+}
+
+// ReadRequestHeaders will read new requests without parsing the arguments. It will return a collection of requests, an
+// indication if these requests are in batch form or an error when the incoming message could not be read/parsed.
+func (c *jsonCodec) ReadRequestHeaders() ([]rpcRequest, bool, RPCError) {
+	var incomingMsg json.RawMessage
+	if err := c.d.Decode(&incomingMsg); err != nil {
+		return nil, false, &invalidRequestError{err.Error()}
+	}
+
+	if isBatch(incomingMsg) {
+		return parseBatchRequest(incomingMsg)
+	}
+
+	return parseRequest(incomingMsg)
+}
+
+// parseRequest will parse a single request from the given RawMessage. It will return the parsed request, an indication
+// if the request was a batch or an error when the request could not be parsed.
+func parseRequest(incomingMsg json.RawMessage) ([]rpcRequest, bool, RPCError) {
+	var in jsonRequest
+	if err := json.Unmarshal(incomingMsg, &in); err != nil {
+		return nil, false, &invalidMessageError{err.Error()}
+	}
+
+	if in.Id == nil {
+		return nil, false, &invalidMessageError{"Server cannot handle notifications"}
+	}
+
+	// subscribe are special, they will always use `subscribeMethod` as service method
+	if in.Method == subscribeMethod {
+		reqs := []rpcRequest{rpcRequest{id: *in.Id, isPubSub: true}}
+		if len(in.Payload) > 0 {
+			// first param must be subscription name
+			var subscribeMethod [1]string
+			if err := json.Unmarshal(in.Payload, &subscribeMethod); err != nil {
+				glog.V(logger.Debug).Infof("Unable to parse subscription method: %v\n", err)
+				return nil, false, &invalidRequestError{"Unable to parse subscription request"}
+			}
+
+			// all subscriptions are made on the eth service
+			reqs[0].service, reqs[0].method = "eth", subscribeMethod[0]
+			reqs[0].params = in.Payload
+			return reqs, false, nil
+		}
+		return nil, false, &invalidRequestError{"Unable to parse subscription request"}
+	}
+
+	if in.Method == unsubscribeMethod {
+		return []rpcRequest{rpcRequest{id: *in.Id, isPubSub: true,
+			method: unsubscribeMethod, params: in.Payload}}, false, nil
+	}
+
+	// regular RPC call
+	elems := strings.Split(in.Method, serviceMethodSeparator)
+	if len(elems) != 2 {
+		return nil, false, &methodNotFoundError{in.Method, ""}
+	}
+
+	if len(in.Payload) == 0 {
+		return []rpcRequest{rpcRequest{service: elems[0], method: elems[1], id: *in.Id}}, false, nil
+	}
+
+	return []rpcRequest{rpcRequest{service: elems[0], method: elems[1], id: *in.Id, params: in.Payload}}, false, nil
+}
+
+// parseBatchRequest will parse a batch request into a collection of requests from the given RawMessage, an indication
+// if the request was a batch or an error when the request could not be read.
+func parseBatchRequest(incomingMsg json.RawMessage) ([]rpcRequest, bool, RPCError) {
+	var in []jsonRequest
+	if err := json.Unmarshal(incomingMsg, &in); err != nil {
+		return nil, false, &invalidMessageError{err.Error()}
+	}
+
+	requests := make([]rpcRequest, len(in))
+	for i, r := range in {
+		if r.Id == nil {
+			return nil, true, &invalidMessageError{"Server cannot handle notifications"}
+		}
+
+		// (un)subscribe are special, they will always use the same service.method
+		if r.Method == subscribeMethod {
+			requests[i] = rpcRequest{id: *r.Id, isPubSub: true}
+			if len(r.Payload) > 0 {
+				var subscribeMethod [1]string
+				if err := json.Unmarshal(r.Payload, &subscribeMethod); err != nil {
+					glog.V(logger.Debug).Infof("Unable to parse subscription method: %v\n", err)
+					return nil, false, &invalidRequestError{"Unable to parse subscription request"}
+				}
+
+				// all subscriptions are made on the eth service
+				requests[i].service, requests[i].method = "eth", subscribeMethod[0]
+				requests[i].params = r.Payload
+				continue
+			}
+
+			return nil, true, &invalidRequestError{"Unable to parse (un)subscribe request arguments"}
+		}
+
+		if r.Method == unsubscribeMethod {
+			requests[i] = rpcRequest{id: *r.Id, isPubSub: true, method: unsubscribeMethod, params: r.Payload}
+			continue
+		}
+
+		elems := strings.Split(r.Method, serviceMethodSeparator)
+		if len(elems) != 2 {
+			return nil, true, &methodNotFoundError{r.Method, ""}
+		}
+
+		if len(r.Payload) == 0 {
+			requests[i] = rpcRequest{service: elems[0], method: elems[1], id: *r.Id, params: nil}
+		} else {
+			requests[i] = rpcRequest{service: elems[0], method: elems[1], id: *r.Id, params: r.Payload}
+		}
+	}
+
+	return requests, true, nil
+}
+
+// ParseRequestArguments tries to parse the given params (json.RawMessage) with the given types. It returns the parsed
+// values or an error when the parsing failed.
+func (c *jsonCodec) ParseRequestArguments(argTypes []reflect.Type, params interface{}) ([]reflect.Value, RPCError) {
+	if args, ok := params.(json.RawMessage); !ok {
+		return nil, &invalidParamsError{"Invalid params supplied"}
+	} else {
+		return parsePositionalArguments(args, argTypes)
+	}
+}
+
+func countArguments(args json.RawMessage) (int, error) {
+	var cnt []interface{}
+	if err := json.Unmarshal(args, &cnt); err != nil {
+		return -1, nil
+	}
+	return len(cnt), nil
+}
+
+// parsePositionalArguments tries to parse the given args to an array of values with the given types. It returns the
+// parsed values or an error when the args could not be parsed.
+func parsePositionalArguments(args json.RawMessage, argTypes []reflect.Type) ([]reflect.Value, RPCError) {
+	argValues := make([]reflect.Value, len(argTypes))
+	params := make([]interface{}, len(argTypes))
+
+	n, err := countArguments(args)
+	if err != nil {
+		return nil, &invalidParamsError{err.Error()}
+	}
+	if n != len(argTypes) {
+		return nil, &invalidParamsError{fmt.Sprintf("insufficient params, want %d have %d", len(argTypes), n)}
+	}
+
+	for i, t := range argTypes {
+		if t.Kind() == reflect.Ptr {
+			// values must be pointers for the Unmarshal method, reflect.
+			// Dereference otherwise reflect.New would create **SomeType
+			argValues[i] = reflect.New(t.Elem())
+			params[i] = argValues[i].Interface()
+
+			// when not specified blockNumbers are by default latest (-1)
+			if blockNumber, ok := params[i].(*BlockNumber); ok {
+				*blockNumber = BlockNumber(-1)
+			}
+		} else {
+			argValues[i] = reflect.New(t)
+			params[i] = argValues[i].Interface()
+
+			// when not specified blockNumbers are by default latest (-1)
+			if blockNumber, ok := params[i].(*BlockNumber); ok {
+				*blockNumber = BlockNumber(-1)
+			}
+		}
+	}
+
+	if err := json.Unmarshal(args, &params); err != nil {
+		return nil, &invalidParamsError{err.Error()}
+	}
+
+	// Convert pointers back to values where necessary
+	for i, a := range argValues {
+		if a.Kind() != argTypes[i].Kind() {
+			argValues[i] = reflect.Indirect(argValues[i])
+		}
+	}
+
+	return argValues, nil
+}
+
+// CreateResponse will create a JSON-RPC success response with the given id and reply as result.
+func (c *jsonCodec) CreateResponse(id int64, reply interface{}) interface{} {
+	if isHexNum(reflect.TypeOf(reply)) {
+		return &jsonSuccessResponse{Version: jsonRPCVersion, Id: id, Result: fmt.Sprintf(`%#x`, reply)}
+	}
+	return &jsonSuccessResponse{Version: jsonRPCVersion, Id: id, Result: reply}
+}
+
+// CreateErrorResponse will create a JSON-RPC error response with the given id and error.
+func (c *jsonCodec) CreateErrorResponse(id *int64, err RPCError) interface{} {
+	return &jsonErrResponse{Version: jsonRPCVersion, Id: id, Error: jsonError{Code: err.Code(), Message: err.Error()}}
+}
+
+// CreateErrorResponseWithInfo will create a JSON-RPC error response with the given id and error.
+// info is optional and contains additional information about the error. When an empty string is passed it is ignored.
+func (c *jsonCodec) CreateErrorResponseWithInfo(id *int64, err RPCError, info interface{}) interface{} {
+	return &jsonErrResponse{Version: jsonRPCVersion, Id: id,
+		Error: jsonError{Code: err.Code(), Message: err.Error(), Data: info}}
+}
+
+// CreateNotification will create a JSON-RPC notification with the given subscription id and event as params.
+func (c *jsonCodec) CreateNotification(subid string, event interface{}) interface{} {
+	if isHexNum(reflect.TypeOf(event)) {
+		return &jsonNotification{Version: jsonRPCVersion, Method: notificationMethod,
+			Params: jsonSubscription{Subscription: subid, Result: fmt.Sprintf(`%#x`, event)}}
+	}
+
+	return &jsonNotification{Version: jsonRPCVersion, Method: notificationMethod,
+		Params: jsonSubscription{Subscription: subid, Result: event}}
+}
+
+// Write message to client
+func (c *jsonCodec) Write(res interface{}) error {
+	return c.e.Encode(res)
+}
+
+// Close the underlying connection
+func (c *jsonCodec) Close() {
+	if atomic.CompareAndSwapInt32(&c.isClosed, 0, 1) {
+		close(c.closed)
+		c.rw.Close()
+	}
+}
+
+// Closed returns a channel which will be closed when Close is called
+func (c *jsonCodec) Closed() <-chan interface{} {
+	return c.closed
+}