path: root/rpc/codec/json.go

package codec

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

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

const (
    READ_TIMEOUT      = 15 // read timeout in seconds
    MAX_REQUEST_SIZE  = 1024 * 1024
    MAX_RESPONSE_SIZE = 1024 * 1024
)

// Json serialization support
type JsonCodec struct {
    c net.Conn
    d *json.Decoder
}

// Create new JSON coder instance
func NewJsonCoder(conn net.Conn) ApiCoder {
    return &JsonCodec{
        c: conn,
        d: json.NewDecoder(conn),
    }
}

// Serialize obj to JSON and write it to conn
func (self *JsonCodec) ReadRequest() (requests []*shared.Request, isBatch bool, err error) {

    deadline := time.Now().Add(READ_TIMEOUT * time.Second)
    if err := self.c.SetDeadline(deadline); err != nil {
        return nil, false, err
    }

    for {
        var err error
        singleRequest := shared.Request{}
        if err = self.d.Decode(&singleRequest); err == nil {
            requests := make([]*shared.Request, 1)
            requests[0] = &singleRequest
            return requests, false, nil
        }

        fmt.Printf("err %T %v\n", err)

        if opErr, ok := err.(*net.OpError); ok {
            if opErr.Timeout() {
                break
            }
        }

        requests = make([]*shared.Request, 0)
        if err = self.d.Decode(&requests); err == nil {
            return requests, true, nil
        }

        if opErr, ok := err.(*net.OpError); ok {
            if opErr.Timeout() {
                break
            }
        }
    }

    self.c.Close() // timeout
    return nil, false, fmt.Errorf("Timeout reading request")
}

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()
}