path: root/rpc/codec/json.go

// 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 codec

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

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

const (
    READ_TIMEOUT      = 60 // 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),
    }
}

// Read incoming request and parse it to RPC request
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
    }

    var incoming json.RawMessage
    err = self.d.Decode(&incoming)
    if err == nil {
        isBatch = incoming[0] == '['
        if isBatch {
            requests = make([]*shared.Request, 0)
            err = json.Unmarshal(incoming, &requests)
        } else {
            requests = make([]*shared.Request, 1)
            var singleRequest shared.Request
            if err = json.Unmarshal(incoming, &singleRequest); err == nil {
                requests[0] = &singleRequest
            }
        }
        return
    }

    self.c.Close()
    return nil, false, err
}

func (self *JsonCodec) Recv() (interface{}, error) {
    var msg json.RawMessage
    err := self.d.Decode(&msg)
    if err != nil {
        self.c.Close()
        return nil, err
    }

    return msg, err
}

func (self *JsonCodec) ReadResponse() (interface{}, error) {
    in, err := self.Recv()
    if err != nil {
        return nil, err
    }

    if msg, ok := in.(json.RawMessage); ok {
        var req *shared.Request
        if err = json.Unmarshal(msg, &req); err == nil && strings.HasPrefix(req.Method, "agent_") {
            return req, nil
        }

        var failure *shared.ErrorResponse
        if err = json.Unmarshal(msg, &failure); err == nil && failure.Error != nil {
            return failure, fmt.Errorf(failure.Error.Message)
        }

        var success *shared.SuccessResponse
        if err = json.Unmarshal(msg, &success); err == nil {
            return success, nil
        }
    }

    return in, err
}

// 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()
}