iot_server/internal/pkg/packets/pubrec.go

89 lines
2.2 KiB
Go

package packets
import (
"bytes"
"fmt"
"io"
"github.com/winc-link/hummingbird/internal/pkg/codes"
)
// Pubrec represents the MQTT Pubrec packet.
type Pubrec struct {
Version Version
FixHeader *FixHeader
PacketID PacketID
// V5
Code byte
Properties *Properties
}
func (p *Pubrec) String() string {
return fmt.Sprintf("Pubrec, Version: %v, Code %v, Pid: %v, Properties: %s", p.Version, p.Code, p.PacketID, p.Properties)
}
// NewPubrecPacket returns a Pubrec instance by the given FixHeader and io.Reader.
func NewPubrecPacket(fh *FixHeader, version Version, r io.Reader) (*Pubrec, error) {
p := &Pubrec{FixHeader: fh, Version: version}
err := p.Unpack(r)
if err != nil {
return nil, err
}
return p, nil
}
// NewPubrel returns the Pubrel struct related to the Pubrec struct in QoS 2.
func (p *Pubrec) NewPubrel() *Pubrel {
pub := &Pubrel{FixHeader: &FixHeader{PacketType: PUBREL, Flags: FlagPubrel}}
pub.PacketID = p.PacketID
return pub
}
// Pack encodes the packet struct into bytes and writes it into io.Writer.
func (p *Pubrec) Pack(w io.Writer) error {
p.FixHeader = &FixHeader{PacketType: PUBREC, Flags: FlagReserved}
bufw := &bytes.Buffer{}
writeUint16(bufw, p.PacketID)
if p.Version == Version5 && (p.Code != codes.Success || p.Properties != nil) {
bufw.WriteByte(p.Code)
p.Properties.Pack(bufw, PUBREC)
}
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 *Pubrec) 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 p.FixHeader.RemainLength == 2 {
p.Code = codes.Success
return nil
}
if p.Version == Version5 {
p.Properties = &Properties{}
if p.Code, err = bufr.ReadByte(); err != nil {
return codes.ErrMalformed
}
if !ValidateCode(PUBREC, p.Code) {
return codes.ErrProtocol
}
return p.Properties.Unpack(bufr, PUBREC)
}
return nil
}