path: root/rpc/codec/json.go

package codec

import (
    "encoding/json"
    "fmt"
    "net"
    "time"

    "github.com/ethereum/go-ethereum/rpc/shared"
)

const (
    MAX_REQUEST_SIZE  = 1024 * 1024
    MAX_RESPONSE_SIZE = 1024 * 1024
)

// Json serialization support
type JsonCodec struct {
    c             net.Conn
    buffer        []byte
    bytesInBuffer int
}

// Create new JSON coder instance
func NewJsonCoder(conn net.Conn) ApiCoder {
    return &JsonCodec{
        c:             conn,
        buffer:        make([]byte, MAX_REQUEST_SIZE),
        bytesInBuffer: 0,
    }
}

// Serialize obj to JSON and write it to conn
func (self *JsonCodec) ReadRequest() (requests []*shared.Request, isBatch bool, err error) {
    n, err := self.c.Read(self.buffer[self.bytesInBuffer:])
    if err != nil {
        self.bytesInBuffer = 0
        return nil, false, err
    }

    self.bytesInBuffer += n

    singleRequest := shared.Request{}
    err = json.Unmarshal(self.buffer[:self.bytesInBuffer], &singleRequest)
    if err == nil {
        self.bytesInBuffer = 0
        requests := make([]*shared.Request, 1)
        requests[0] = &singleRequest
        return requests, false, nil
    }

    requests = make([]*shared.Request, 0)
    err = json.Unmarshal(self.buffer[:self.bytesInBuffer], &requests)
    if err == nil {
        self.bytesInBuffer = 0
        return requests, true, nil
    }

    return nil, false, err
}

func (self *JsonCodec) ReadResponse() (interface{}, error) {
    bytesInBuffer := 0
    buf := make([]byte, MAX_RESPONSE_SIZE)

    deadline := time.Now().Add(15 * time.Second)
    self.c.SetDeadline(deadline)

    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()
}