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|
package codec
import (
"encoding/json"
"fmt"
"net"
"time"
"github.com/ethereum/go-ethereum/rpc/shared"
)
const (
READ_TIMEOUT = 60 // in seconds
MAX_REQUEST_SIZE = 1024 * 1024
MAX_RESPONSE_SIZE = 1024 * 1024
)
var (
// No new requests in buffer
EmptyRequestQueueError = fmt.Errorf("No incoming requests")
// Next request in buffer isn't yet complete
IncompleteRequestError = fmt.Errorf("Request incomplete")
)
// Json serialization support
type JsonCodec struct {
c net.Conn
reqBuffer []byte
bytesInReqBuffer int
reqLastPos int
}
// Create new JSON coder instance
func NewJsonCoder(conn net.Conn) ApiCoder {
return &JsonCodec{
c: conn,
reqBuffer: make([]byte, MAX_REQUEST_SIZE),
bytesInReqBuffer: 0,
reqLastPos: 0,
}
}
// Indication if the next request in the buffer is a batch request
func (self *JsonCodec) isNextBatchReq() (bool, error) {
for i := 0; i < self.bytesInReqBuffer; i++ {
switch self.reqBuffer[i] {
case 0x20, 0x09, 0x0a, 0x0d: // allow leading whitespace (JSON whitespace RFC4627)
continue
case 0x7b: // single req
return false, nil
case 0x5b: // batch req
return true, nil
default:
return false, &json.InvalidUnmarshalError{}
}
}
return false, EmptyRequestQueueError
}
// remove parsed request from buffer
func (self *JsonCodec) resetReqbuffer(pos int) {
copy(self.reqBuffer, self.reqBuffer[pos:self.bytesInReqBuffer])
self.reqLastPos = 0
self.bytesInReqBuffer -= pos
}
// parse request in buffer
func (self *JsonCodec) nextRequest() (requests []*shared.Request, isBatch bool, err error) {
if isBatch, err := self.isNextBatchReq(); err == nil {
if isBatch {
requests = make([]*shared.Request, 0)
for ; self.reqLastPos <= self.bytesInReqBuffer; self.reqLastPos++ {
if err = json.Unmarshal(self.reqBuffer[:self.reqLastPos], &requests); err == nil {
self.resetReqbuffer(self.reqLastPos)
return requests, true, nil
}
}
return nil, true, IncompleteRequestError
} else {
request := shared.Request{}
for ; self.reqLastPos <= self.bytesInReqBuffer; self.reqLastPos++ {
if err = json.Unmarshal(self.reqBuffer[:self.reqLastPos], &request); err == nil {
requests := make([]*shared.Request, 1)
requests[0] = &request
self.resetReqbuffer(self.reqLastPos)
return requests, false, nil
}
}
return nil, true, IncompleteRequestError
}
} else {
return nil, false, err
}
}
// Serialize obj to JSON and write it to conn
func (self *JsonCodec) ReadRequest() (requests []*shared.Request, isBatch bool, err error) {
if self.bytesInReqBuffer != 0 {
req, batch, err := self.nextRequest()
if err == nil {
return req, batch, err
}
if err != IncompleteRequestError {
return nil, false, err
}
}
// no/incomplete request in buffer -> read more data first
deadline := time.Now().Add(READ_TIMEOUT * time.Second)
if err := self.c.SetDeadline(deadline); err != nil {
return nil, false, err
}
var retErr error
for {
n, err := self.c.Read(self.reqBuffer[self.bytesInReqBuffer:])
if err != nil {
retErr = err
break
}
self.bytesInReqBuffer += n
requests, isBatch, err := self.nextRequest()
if err == nil {
return requests, isBatch, nil
}
if err == IncompleteRequestError || err == EmptyRequestQueueError {
continue // need more data
}
retErr = err
break
}
self.c.Close()
return nil, false, retErr
}
func (self *JsonCodec) ReadResponse() (interface{}, error) {
bytesInBuffer := 0
buf := make([]byte, MAX_RESPONSE_SIZE)
deadline := time.Now().Add(READ_TIMEOUT * time.Second)
if err := self.c.SetDeadline(deadline); err != nil {
return nil, err
}
for {
n, err := self.c.Read(buf[bytesInBuffer:])
if err != nil {
return nil, err
}
bytesInBuffer += n
var success shared.SuccessResponse
if err = json.Unmarshal(buf[:bytesInBuffer], &success); err == nil {
return success, nil
}
var failure shared.ErrorResponse
if err = json.Unmarshal(buf[:bytesInBuffer], &failure); err == nil && failure.Error != nil {
return failure, nil
}
}
self.c.Close()
return nil, fmt.Errorf("Unable to read response")
}
// Decode data
func (self *JsonCodec) Decode(data []byte, msg interface{}) error {
return json.Unmarshal(data, msg)
}
// Encode message
func (self *JsonCodec) Encode(msg interface{}) ([]byte, error) {
return json.Marshal(msg)
}
// Parse JSON data from conn to obj
func (self *JsonCodec) WriteResponse(res interface{}) error {
data, err := json.Marshal(res)
if err != nil {
self.c.Close()
return err
}
bytesWritten := 0
for bytesWritten < len(data) {
n, err := self.c.Write(data[bytesWritten:])
if err != nil {
self.c.Close()
return err
}
bytesWritten += n
}
return nil
}
// Close decoder and encoder
func (self *JsonCodec) Close() {
self.c.Close()
}
|
