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package packets
import (
"bytes"
"fmt"
"github.com/pborman/uuid"
"io"
)
//SubscribePacket is an internal representation of the fields of the
//Subscribe MQTT packet
type SubscribePacket struct {
FixedHeader
MessageID uint16
Topics []string
Qoss []byte
uuid uuid.UUID
}
func (s *SubscribePacket) String() string {
str := fmt.Sprintf("%s\n", s.FixedHeader)
str += fmt.Sprintf("MessageID: %d topics: %s", s.MessageID, s.Topics)
return str
}
func (s *SubscribePacket) Write(w io.Writer) error {
var body bytes.Buffer
var err error
body.Write(encodeUint16(s.MessageID))
for i, topic := range s.Topics {
body.Write(encodeString(topic))
body.WriteByte(s.Qoss[i])
}
s.FixedHeader.RemainingLength = body.Len()
packet := s.FixedHeader.pack()
packet.Write(body.Bytes())
_, err = packet.WriteTo(w)
return err
}
//Unpack decodes the details of a ControlPacket after the fixed
//header has been read
func (s *SubscribePacket) Unpack(b io.Reader) {
s.MessageID = decodeUint16(b)
payloadLength := s.FixedHeader.RemainingLength - 2
for payloadLength > 0 {
topic := decodeString(b)
s.Topics = append(s.Topics, topic)
qos := decodeByte(b)
s.Qoss = append(s.Qoss, qos)
payloadLength -= 2 + len(topic) + 1 //2 bytes of string length, plus string, plus 1 byte for Qos
}
}
//Details returns a Details struct containing the Qos and
//MessageID of this ControlPacket
func (s *SubscribePacket) Details() Details {
return Details{Qos: 1, MessageID: s.MessageID}
}
//UUID returns the unique ID assigned to the ControlPacket when
//it was originally received. Note: this is not related to the
//MessageID field for MQTT packets
func (s *SubscribePacket) UUID() uuid.UUID {
return s.uuid
}
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