connack.go

package wkproto

import (
	"fmt"

	"github.com/pkg/errors"
)

// ConnackPacket 连接回执包
type ConnackPacket struct {
	Framer
	ServerVersion uint8      // 服务端版本
	ServerKey     string     // 服务端的DH公钥
	Salt          string     // salt
	TimeDiff      int64      // 客户端时间与服务器的差值，单位毫秒。
	ReasonCode    ReasonCode // 原因码
	NodeId        uint64     // 节点Id
}

// GetFrameType 获取包类型
func (c ConnackPacket) GetFrameType() FrameType {
	return CONNACK
}
func (c ConnackPacket) String() string {
	return fmt.Sprintf("TimeDiff: %d ReasonCode:%s", c.TimeDiff, c.ReasonCode.String())
}

func encodeConnack(connack *ConnackPacket, enc *Encoder, version uint8) error {
	if connack.GetHasServerVersion() {
		enc.WriteUint8(connack.ServerVersion)
	}
	enc.WriteInt64(connack.TimeDiff)
	_ = enc.WriteByte(connack.ReasonCode.Byte())
	enc.WriteString(connack.ServerKey)
	enc.WriteString(connack.Salt)
	if version >= 4 {
		enc.WriteUint64(connack.NodeId)
	}
	return nil
}

func encodeConnackSize(packet *ConnackPacket, version uint8) int {
	size := 0
	if packet.GetHasServerVersion() {
		size += VersionByteSize
	}
	size += TimeDiffByteSize
	size += ReasonCodeByteSize
	size += (len(packet.ServerKey) + StringFixLenByteSize)
	size += (len(packet.Salt) + StringFixLenByteSize)
	if version >= 4 {
		size += NodeIdByteSize
	}
	return size
}

func decodeConnack(frame Frame, data []byte, version uint8) (Frame, error) {
	dec := NewDecoder(data)
	connackPacket := &ConnackPacket{}
	connackPacket.Framer = frame.(Framer)

	var err error

	if frame.GetHasServerVersion() {
		if connackPacket.ServerVersion, err = dec.Uint8(); err != nil {
			return nil, errors.Wrap(err, "解码version失败！")
		}
	}

	if connackPacket.TimeDiff, err = dec.Int64(); err != nil {
		return nil, errors.Wrap(err, "解码TimeDiff失败！")
	}
	var reasonCode uint8
	if reasonCode, err = dec.Uint8(); err != nil {
		return nil, errors.Wrap(err, "解码ReasonCode失败！")
	}
	connackPacket.ReasonCode = ReasonCode(reasonCode)

	if connackPacket.ServerKey, err = dec.String(); err != nil {
		return nil, errors.Wrap(err, "解码ServerKey失败！")
	}
	if connackPacket.Salt, err = dec.String(); err != nil {
		return nil, errors.Wrap(err, "解码Salt失败！")
	}

	if version >= 4 {
		if connackPacket.NodeId, err = dec.Uint64(); err != nil {
			return nil, errors.Wrap(err, "解码NodeId失败！")
		}
	}

	return connackPacket, nil
}