/
connack.go
89 lines (79 loc) · 2.02 KB
/
connack.go
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package packets
import (
"bytes"
"fmt"
"io"
"github.com/DrmagicE/gmqtt/pkg/codes"
)
// Connack represents the MQTT Connack packet
type Connack struct {
Version Version
FixHeader *FixHeader
Code codes.Code
SessionPresent bool
Properties *Properties
}
func (c *Connack) String() string {
return fmt.Sprintf("Connack, Version: %v, Code:%v, SessionPresent:%v, Properties: %s", c.Version, c.Code, c.SessionPresent, c.Properties)
}
// Pack encodes the packet struct into bytes and writes it into io.Writer.
func (c *Connack) Pack(w io.Writer) error {
var err error
c.FixHeader = &FixHeader{PacketType: CONNACK, Flags: FlagReserved}
bufw := &bytes.Buffer{}
if c.SessionPresent {
bufw.WriteByte(1)
} else {
bufw.WriteByte(0)
}
bufw.WriteByte(c.Code)
if c.Version == Version5 {
c.Properties.Pack(bufw, CONNACK)
}
c.FixHeader.RemainLength = bufw.Len()
err = c.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 (c *Connack) Unpack(r io.Reader) error {
restBuffer := make([]byte, c.FixHeader.RemainLength)
_, err := io.ReadFull(r, restBuffer)
if err != nil {
return codes.ErrMalformed
}
bufr := bytes.NewBuffer(restBuffer)
sp, err := bufr.ReadByte()
if (127 & (sp >> 1)) > 0 {
return codes.ErrMalformed
}
c.SessionPresent = sp == 1
code, err := bufr.ReadByte()
if err != nil {
return codes.ErrMalformed
}
c.Code = code
if c.Version == Version5 {
if !ValidateCode(CONNACK, code) {
return codes.ErrProtocol
}
c.Properties = &Properties{}
return c.Properties.Unpack(bufr, CONNACK)
}
return nil
}
// NewConnackPacket returns a Connack instance by the given FixHeader and io.Reader
func NewConnackPacket(fh *FixHeader, version Version, r io.Reader) (*Connack, error) {
p := &Connack{FixHeader: fh, Version: Version5}
if fh.Flags != FlagReserved {
return nil, codes.ErrMalformed
}
err := p.Unpack(r)
if err != nil {
return nil, err
}
return p, err
}