maeqtt/mqtt/packets/Disconnect.go

package packets

import (
	"bufio"
	"bytes"
	"errors"
	"io"

	"badat.dev/maeqtt/v2/mqtt/properties"
)

type DisconnectReasonCode byte

const (
	DisconnectReasonCodeNormal                           DisconnectReasonCode = 0
	DisconnectReasonCodeWithWill                         DisconnectReasonCode = 0
	DisconnectReasonCodeUnspecified                                           = 128
	DisconnectReasonCodeMalformedPacket                                       = 129
	DisconnectReasonCodeProtocolError                                         = 130
	DisconnectReasonCodeImplErorr                                             = 131
	DisconnectReasonCodeNotAuthorized                                         = 135
	DisconnectReasonCodeServerBusy                                            = 137
	DisconnectReasonServerShuttingDown                                        = 139
	DisconnectReasonCodeKeepAliveTimeout                                      = 141
	DisconnectReasonCodeSessionTakenOver                                      = 142
	DisconnectReasonCodeTopicFilterInvalid                                    = 143
	DisconnectReasonCodeTopicNameInvalid                                      = 144
	DisconnectReasonCodeReceiveMaxiumExceeded                                 = 147
	DisconnectReasonCodeTopicAliasInvalid                                     = 148
	DisconnectReasonCodePacketTooLarge                                        = 149
	DisconnectReasonCodeMessageRateTooHigh                                    = 150
	DisconnectReasonCodeQuotaExceeded                                         = 151
	DisconnectReasonCodeAdminiAction                                          = 152
	DisconnectReasonCodePayloadFormatInvalid                                  = 153
	DisconnectReasonCodeRetainNotSupported                                    = 154
	DisconnectReasonCodeQoSNotSupported                                       = 155
	DisconnectReasonCodeUseAnotherServer                                      = 156
	DisconnectReasonCodeServerMoved                                           = 157
	DisconnectReasonCodeSharedSubscriptionNotSupported                        = 158
	DisconnectReasonCodeConnectionRateExceeded                                = 159
	DisconnectReasonCodeMaximumConnectTime                                    = 160
	DisconnectReasonCodeSubscriptionIdNotSupported                            = 161
	DisconnectReasonCodeWildcardSubscriptionNotSupported                      = 162
)

type DisconnectPacket struct {
	ReasonCode DisconnectReasonCode
	Properties properties.DisconnectPacketProperties
}

func parseDisconnectPacket(control controlPacket) (DisconnectPacket, error) {
	packet := DisconnectPacket{}

	if control.packetType != PacketTypeDisconnect {
		panic("Wrong packet type for parseDisconnect")
	}
	if control.flags != 0 {
		return packet, errors.New("Malformed disconnect packet")
	}

	r := bufio.NewReader(control.reader)

	// If there is less then a byte in the reader assume the reason code == 0
	reason, err := r.ReadByte()
	if err == io.EOF {
		reason = 0
	} else if err != nil {
		return packet, err
	}
	packet.ReasonCode = DisconnectReasonCode(reason)

	// If there are less than 2 bytes remaining in the reader assume that the packet has no properties
	_, err = r.Peek(2)
	if err == nil {
		err = properties.ParseProperties(r, packet.Properties.ArrayOf())
	} else if err != io.EOF {
		return packet, err
	} else if err == io.EOF {
		err = nil
	}

	return packet, err
}

func (p DisconnectPacket) Write(w io.Writer) error {
	buf := bytes.NewBuffer([]byte{})
	buf.WriteByte(byte(p.ReasonCode))
	err := properties.WriteProps(w, p.Properties.ArrayOf())
	if err != nil {
		return err
	}

	control := controlPacket{
		packetType: PacketTypeDisconnect,
		flags:      0,
		reader:     buf,
	}
	return control.write(w)
}

func (p DisconnectPacket) Visit(v PacketVisitor) {
	v.VisitDisconnect(p)
}