iot_server/internal/pkg/packets/unsuback.go

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2023-08-28 06:49:44 +00:00
package packets
import (
"bytes"
"fmt"
"io"
"github.com/winc-link/hummingbird/internal/pkg/codes"
)
// Unsuback represents the MQTT Unsuback packet.
type Unsuback struct {
Version Version
FixHeader *FixHeader
PacketID PacketID
Properties *Properties
Payload []codes.Code
}
func (p *Unsuback) String() string {
return fmt.Sprintf("Unsuback, Version: %v, Pid: %v, Payload: %v, Properties: %s", p.Version, p.PacketID, p.Payload, p.Properties)
}
// Pack encodes the packet struct into bytes and writes it into io.Writer.
func (p *Unsuback) Pack(w io.Writer) error {
p.FixHeader = &FixHeader{PacketType: UNSUBACK, Flags: FlagReserved}
bufw := &bytes.Buffer{}
writeUint16(bufw, p.PacketID)
if p.Version == Version5 {
p.Properties.Pack(bufw, UNSUBACK)
}
bufw.Write(p.Payload)
p.FixHeader.RemainLength = bufw.Len()
err := p.FixHeader.Pack(w)
if err != nil {
return err
}
_, err = bufw.WriteTo(w)
return err
}
// Unpack read the packet bytes from io.Reader and decodes it into the packet struct.
func (p *Unsuback) Unpack(r io.Reader) error {
restBuffer := make([]byte, p.FixHeader.RemainLength)
_, err := io.ReadFull(r, restBuffer)
if err != nil {
return codes.ErrMalformed
}
bufr := bytes.NewBuffer(restBuffer)
p.PacketID, err = readUint16(bufr)
if err != nil {
return err
}
if IsVersion3X(p.Version) {
return nil
}
p.Properties = &Properties{}
err = p.Properties.Unpack(bufr, UNSUBACK)
if err != nil {
return err
}
for {
b, err := bufr.ReadByte()
if err != nil {
return codes.ErrMalformed
}
if p.Version == Version5 && !ValidateCode(UNSUBACK, b) {
return codes.ErrProtocol
}
p.Payload = append(p.Payload, b)
if bufr.Len() == 0 {
return nil
}
}
}
// NewUnsubackPacket returns a Unsuback instance by the given FixHeader and io.Reader.
func NewUnsubackPacket(fh *FixHeader, version Version, r io.Reader) (*Unsuback, error) {
p := &Unsuback{FixHeader: fh, Version: version}
if fh.Flags != FlagReserved {
return nil, codes.ErrMalformed
}
err := p.Unpack(r)
if err != nil {
return nil, err
}
return p, err
}