// 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 rpc
import (
"bytes"
"context"
"encoding/json"
"errors"
"fmt"
"io"
"reflect"
"strings"
"sync"
"time"
)
const (
vsn = "2.0"
serviceMethodSeparator = "_"
subscribeMethodSuffix = "_subscribe"
unsubscribeMethodSuffix = "_unsubscribe"
notificationMethodSuffix = "_subscription"
defaultWriteTimeout = 10 * time.Second // used if context has no deadline
)
var null = json.RawMessage("null")
type subscriptionResult struct {
ID string `json:"subscription"`
Result json.RawMessage `json:"result,omitempty"`
}
// A value of this type can a JSON-RPC request, notification, successful response or
// error response. Which one it is depends on the fields.
type jsonrpcMessage struct {
Version string `json:"jsonrpc,omitempty"`
ID json.RawMessage `json:"id,omitempty"`
Method string `json:"method,omitempty"`
Params json.RawMessage `json:"params,omitempty"`
Error *jsonError `json:"error,omitempty"`
Result json.RawMessage `json:"result,omitempty"`
}
func (msg *jsonrpcMessage) isNotification() bool {
return msg.ID == nil && msg.Method != ""
}
func (msg *jsonrpcMessage) isCall() bool {
return msg.hasValidID() && msg.Method != ""
}
func (msg *jsonrpcMessage) isResponse() bool {
return msg.hasValidID() && msg.Method == "" && msg.Params == nil && (msg.Result != nil || msg.Error != nil)
}
func (msg *jsonrpcMessage) hasValidID() bool {
return len(msg.ID) > 0 && msg.ID[0] != '{' && msg.ID[0] != '['
}
func (msg *jsonrpcMessage) isSubscribe() bool {
return strings.HasSuffix(msg.Method, subscribeMethodSuffix)
}
func (msg *jsonrpcMessage) isUnsubscribe() bool {
return strings.HasSuffix(msg.Method, unsubscribeMethodSuffix)
}
func (msg *jsonrpcMessage) namespace() string {
elem := strings.SplitN(msg.Method, serviceMethodSeparator, 2)
return elem[0]
}
func (msg *jsonrpcMessage) String() string {
b, _ := json.Marshal(msg)
return string(b)
}
func (msg *jsonrpcMessage) errorResponse(err error) *jsonrpcMessage {
resp := errorMessage(err)
resp.ID = msg.ID
return resp
}
func (msg *jsonrpcMessage) response(result interface{}) *jsonrpcMessage {
enc, err := json.Marshal(result)
if err != nil {
// TODO: wrap with 'internal server error'
return msg.errorResponse(err)
}
return &jsonrpcMessage{Version: vsn, ID: msg.ID, Result: enc}
}
func errorMessage(err error) *jsonrpcMessage {
msg := &jsonrpcMessage{Version: vsn, ID: null, Error: &jsonError{
Code: defaultErrorCode,
Message: err.Error(),
}}
ec, ok := err.(Error)
if ok {
msg.Error.Code = ec.ErrorCode()
}
de, ok := err.(DataError)
if ok {
msg.Error.Data = de.ErrorData()
}
return msg
}
type jsonError struct {
Code int `json:"code"`
Message string `json:"message"`
Data interface{} `json:"data,omitempty"`
}
func (err *jsonError) Error() string {
if err.Message == "" {
return fmt.Sprintf("json-rpc error %d", err.Code)
}
return err.Message
}
func (err *jsonError) ErrorCode() int {
return err.Code
}
func (err *jsonError) ErrorData() interface{} {
return err.Data
}
// Conn is a subset of the methods of net.Conn which are sufficient for ServerCodec.
type Conn interface {
io.ReadWriteCloser
SetWriteDeadline(time.Time) error
}
type deadlineCloser interface {
io.Closer
SetWriteDeadline(time.Time) error
}
// ConnRemoteAddr wraps the RemoteAddr operation, which returns a description
// of the peer address of a connection. If a Conn also implements ConnRemoteAddr, this
// description is used in log messages.
type ConnRemoteAddr interface {
RemoteAddr() string
}
// 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 {
remote string
closer sync.Once // close closed channel once
closeCh chan interface{} // closed on Close
decode func(v interface{}) error // decoder to allow multiple transports
encMu sync.Mutex // guards the encoder
encode func(v interface{}) error // encoder to allow multiple transports
conn deadlineCloser
}
// NewFuncCodec creates a codec which uses the given functions to read and write. If conn
// implements ConnRemoteAddr, log messages will use it to include the remote address of
// the connection.
func NewFuncCodec(conn deadlineCloser, encode, decode func(v interface{}) error) ServerCodec {
codec := &jsonCodec{
closeCh: make(chan interface{}),
encode: encode,
decode: decode,
conn: conn,
}
if ra, ok := conn.(ConnRemoteAddr); ok {
codec.remote = ra.RemoteAddr()
}
return codec
}
// NewCodec creates a codec on the given connection. If conn implements ConnRemoteAddr, log
// messages will use it to include the remote address of the connection.
func NewCodec(conn Conn) ServerCodec {
enc := json.NewEncoder(conn)
dec := json.NewDecoder(conn)
dec.UseNumber()
return NewFuncCodec(conn, enc.Encode, dec.Decode)
}
func (c *jsonCodec) remoteAddr() string {
return c.remote
}
func (c *jsonCodec) readBatch() (messages []*jsonrpcMessage, batch