First implementation

This commit is contained in:
2021-10-10 21:03:57 +02:00
parent f8be309c81
commit 0dfd7a595b
344 changed files with 63911 additions and 0 deletions

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package packets
import (
"bytes"
"fmt"
"io"
)
// ConnackPacket is an internal representation of the fields of the
// Connack MQTT packet
type ConnackPacket struct {
FixedHeader
SessionPresent bool
ReturnCode byte
}
func (ca *ConnackPacket) String() string {
return fmt.Sprintf("%s sessionpresent: %t returncode: %d", ca.FixedHeader, ca.SessionPresent, ca.ReturnCode)
}
func (ca *ConnackPacket) Write(w io.Writer) error {
var body bytes.Buffer
var err error
body.WriteByte(boolToByte(ca.SessionPresent))
body.WriteByte(ca.ReturnCode)
ca.FixedHeader.RemainingLength = 2
packet := ca.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 (ca *ConnackPacket) Unpack(b io.Reader) error {
flags, err := decodeByte(b)
if err != nil {
return err
}
ca.SessionPresent = 1&flags > 0
ca.ReturnCode, err = decodeByte(b)
return err
}
// Details returns a Details struct containing the Qos and
// MessageID of this ControlPacket
func (ca *ConnackPacket) Details() Details {
return Details{Qos: 0, MessageID: 0}
}

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package packets
import (
"bytes"
"fmt"
"io"
)
// ConnectPacket is an internal representation of the fields of the
// Connect MQTT packet
type ConnectPacket struct {
FixedHeader
ProtocolName string
ProtocolVersion byte
CleanSession bool
WillFlag bool
WillQos byte
WillRetain bool
UsernameFlag bool
PasswordFlag bool
ReservedBit byte
Keepalive uint16
ClientIdentifier string
WillTopic string
WillMessage []byte
Username string
Password []byte
}
func (c *ConnectPacket) String() string {
var password string
if len(c.Password) > 0 {
password = "<redacted>"
}
return fmt.Sprintf("%s protocolversion: %d protocolname: %s cleansession: %t willflag: %t WillQos: %d WillRetain: %t Usernameflag: %t Passwordflag: %t keepalive: %d clientId: %s willtopic: %s willmessage: %s Username: %s Password: %s", c.FixedHeader, c.ProtocolVersion, c.ProtocolName, c.CleanSession, c.WillFlag, c.WillQos, c.WillRetain, c.UsernameFlag, c.PasswordFlag, c.Keepalive, c.ClientIdentifier, c.WillTopic, c.WillMessage, c.Username, password)
}
func (c *ConnectPacket) Write(w io.Writer) error {
var body bytes.Buffer
var err error
body.Write(encodeString(c.ProtocolName))
body.WriteByte(c.ProtocolVersion)
body.WriteByte(boolToByte(c.CleanSession)<<1 | boolToByte(c.WillFlag)<<2 | c.WillQos<<3 | boolToByte(c.WillRetain)<<5 | boolToByte(c.PasswordFlag)<<6 | boolToByte(c.UsernameFlag)<<7)
body.Write(encodeUint16(c.Keepalive))
body.Write(encodeString(c.ClientIdentifier))
if c.WillFlag {
body.Write(encodeString(c.WillTopic))
body.Write(encodeBytes(c.WillMessage))
}
if c.UsernameFlag {
body.Write(encodeString(c.Username))
}
if c.PasswordFlag {
body.Write(encodeBytes(c.Password))
}
c.FixedHeader.RemainingLength = body.Len()
packet := c.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 (c *ConnectPacket) Unpack(b io.Reader) error {
var err error
c.ProtocolName, err = decodeString(b)
if err != nil {
return err
}
c.ProtocolVersion, err = decodeByte(b)
if err != nil {
return err
}
options, err := decodeByte(b)
if err != nil {
return err
}
c.ReservedBit = 1 & options
c.CleanSession = 1&(options>>1) > 0
c.WillFlag = 1&(options>>2) > 0
c.WillQos = 3 & (options >> 3)
c.WillRetain = 1&(options>>5) > 0
c.PasswordFlag = 1&(options>>6) > 0
c.UsernameFlag = 1&(options>>7) > 0
c.Keepalive, err = decodeUint16(b)
if err != nil {
return err
}
c.ClientIdentifier, err = decodeString(b)
if err != nil {
return err
}
if c.WillFlag {
c.WillTopic, err = decodeString(b)
if err != nil {
return err
}
c.WillMessage, err = decodeBytes(b)
if err != nil {
return err
}
}
if c.UsernameFlag {
c.Username, err = decodeString(b)
if err != nil {
return err
}
}
if c.PasswordFlag {
c.Password, err = decodeBytes(b)
if err != nil {
return err
}
}
return nil
}
// Validate performs validation of the fields of a Connect packet
func (c *ConnectPacket) Validate() byte {
if c.PasswordFlag && !c.UsernameFlag {
return ErrRefusedBadUsernameOrPassword
}
if c.ReservedBit != 0 {
// Bad reserved bit
return ErrProtocolViolation
}
if (c.ProtocolName == "MQIsdp" && c.ProtocolVersion != 3) || (c.ProtocolName == "MQTT" && c.ProtocolVersion != 4) {
// Mismatched or unsupported protocol version
return ErrRefusedBadProtocolVersion
}
if c.ProtocolName != "MQIsdp" && c.ProtocolName != "MQTT" {
// Bad protocol name
return ErrProtocolViolation
}
if len(c.ClientIdentifier) > 65535 || len(c.Username) > 65535 || len(c.Password) > 65535 {
// Bad size field
return ErrProtocolViolation
}
if len(c.ClientIdentifier) == 0 && !c.CleanSession {
// Bad client identifier
return ErrRefusedIDRejected
}
return Accepted
}
// Details returns a Details struct containing the Qos and
// MessageID of this ControlPacket
func (c *ConnectPacket) Details() Details {
return Details{Qos: 0, MessageID: 0}
}

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package packets
import (
"io"
)
// DisconnectPacket is an internal representation of the fields of the
// Disconnect MQTT packet
type DisconnectPacket struct {
FixedHeader
}
func (d *DisconnectPacket) String() string {
return d.FixedHeader.String()
}
func (d *DisconnectPacket) Write(w io.Writer) error {
packet := d.FixedHeader.pack()
_, err := packet.WriteTo(w)
return err
}
// Unpack decodes the details of a ControlPacket after the fixed
// header has been read
func (d *DisconnectPacket) Unpack(b io.Reader) error {
return nil
}
// Details returns a Details struct containing the Qos and
// MessageID of this ControlPacket
func (d *DisconnectPacket) Details() Details {
return Details{Qos: 0, MessageID: 0}
}

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package packets
import (
"bytes"
"encoding/binary"
"errors"
"fmt"
"io"
)
// ControlPacket defines the interface for structs intended to hold
// decoded MQTT packets, either from being read or before being
// written
type ControlPacket interface {
Write(io.Writer) error
Unpack(io.Reader) error
String() string
Details() Details
}
// PacketNames maps the constants for each of the MQTT packet types
// to a string representation of their name.
var PacketNames = map[uint8]string{
1: "CONNECT",
2: "CONNACK",
3: "PUBLISH",
4: "PUBACK",
5: "PUBREC",
6: "PUBREL",
7: "PUBCOMP",
8: "SUBSCRIBE",
9: "SUBACK",
10: "UNSUBSCRIBE",
11: "UNSUBACK",
12: "PINGREQ",
13: "PINGRESP",
14: "DISCONNECT",
}
// Below are the constants assigned to each of the MQTT packet types
const (
Connect = 1
Connack = 2
Publish = 3
Puback = 4
Pubrec = 5
Pubrel = 6
Pubcomp = 7
Subscribe = 8
Suback = 9
Unsubscribe = 10
Unsuback = 11
Pingreq = 12
Pingresp = 13
Disconnect = 14
)
// Below are the const definitions for error codes returned by
// Connect()
const (
Accepted = 0x00
ErrRefusedBadProtocolVersion = 0x01
ErrRefusedIDRejected = 0x02
ErrRefusedServerUnavailable = 0x03
ErrRefusedBadUsernameOrPassword = 0x04
ErrRefusedNotAuthorised = 0x05
ErrNetworkError = 0xFE
ErrProtocolViolation = 0xFF
)
// ConnackReturnCodes is a map of the error codes constants for Connect()
// to a string representation of the error
var ConnackReturnCodes = map[uint8]string{
0: "Connection Accepted",
1: "Connection Refused: Bad Protocol Version",
2: "Connection Refused: Client Identifier Rejected",
3: "Connection Refused: Server Unavailable",
4: "Connection Refused: Username or Password in unknown format",
5: "Connection Refused: Not Authorised",
254: "Connection Error",
255: "Connection Refused: Protocol Violation",
}
var (
ErrorRefusedBadProtocolVersion = errors.New("unacceptable protocol version")
ErrorRefusedIDRejected = errors.New("identifier rejected")
ErrorRefusedServerUnavailable = errors.New("server Unavailable")
ErrorRefusedBadUsernameOrPassword = errors.New("bad user name or password")
ErrorRefusedNotAuthorised = errors.New("not Authorized")
ErrorNetworkError = errors.New("network Error")
ErrorProtocolViolation = errors.New("protocol Violation")
)
// ConnErrors is a map of the errors codes constants for Connect()
// to a Go error
var ConnErrors = map[byte]error{
Accepted: nil,
ErrRefusedBadProtocolVersion: ErrorRefusedBadProtocolVersion,
ErrRefusedIDRejected: ErrorRefusedIDRejected,
ErrRefusedServerUnavailable: ErrorRefusedServerUnavailable,
ErrRefusedBadUsernameOrPassword: ErrorRefusedBadUsernameOrPassword,
ErrRefusedNotAuthorised: ErrorRefusedNotAuthorised,
ErrNetworkError: ErrorNetworkError,
ErrProtocolViolation: ErrorProtocolViolation,
}
// ReadPacket takes an instance of an io.Reader (such as net.Conn) and attempts
// to read an MQTT packet from the stream. It returns a ControlPacket
// representing the decoded MQTT packet and an error. One of these returns will
// always be nil, a nil ControlPacket indicating an error occurred.
func ReadPacket(r io.Reader) (ControlPacket, error) {
var fh FixedHeader
b := make([]byte, 1)
_, err := io.ReadFull(r, b)
if err != nil {
return nil, err
}
err = fh.unpack(b[0], r)
if err != nil {
return nil, err
}
cp, err := NewControlPacketWithHeader(fh)
if err != nil {
return nil, err
}
packetBytes := make([]byte, fh.RemainingLength)
n, err := io.ReadFull(r, packetBytes)
if err != nil {
return nil, err
}
if n != fh.RemainingLength {
return nil, errors.New("failed to read expected data")
}
err = cp.Unpack(bytes.NewBuffer(packetBytes))
return cp, err
}
// NewControlPacket is used to create a new ControlPacket of the type specified
// by packetType, this is usually done by reference to the packet type constants
// defined in packets.go. The newly created ControlPacket is empty and a pointer
// is returned.
func NewControlPacket(packetType byte) ControlPacket {
switch packetType {
case Connect:
return &ConnectPacket{FixedHeader: FixedHeader{MessageType: Connect}}
case Connack:
return &ConnackPacket{FixedHeader: FixedHeader{MessageType: Connack}}
case Disconnect:
return &DisconnectPacket{FixedHeader: FixedHeader{MessageType: Disconnect}}
case Publish:
return &PublishPacket{FixedHeader: FixedHeader{MessageType: Publish}}
case Puback:
return &PubackPacket{FixedHeader: FixedHeader{MessageType: Puback}}
case Pubrec:
return &PubrecPacket{FixedHeader: FixedHeader{MessageType: Pubrec}}
case Pubrel:
return &PubrelPacket{FixedHeader: FixedHeader{MessageType: Pubrel, Qos: 1}}
case Pubcomp:
return &PubcompPacket{FixedHeader: FixedHeader{MessageType: Pubcomp}}
case Subscribe:
return &SubscribePacket{FixedHeader: FixedHeader{MessageType: Subscribe, Qos: 1}}
case Suback:
return &SubackPacket{FixedHeader: FixedHeader{MessageType: Suback}}
case Unsubscribe:
return &UnsubscribePacket{FixedHeader: FixedHeader{MessageType: Unsubscribe, Qos: 1}}
case Unsuback:
return &UnsubackPacket{FixedHeader: FixedHeader{MessageType: Unsuback}}
case Pingreq:
return &PingreqPacket{FixedHeader: FixedHeader{MessageType: Pingreq}}
case Pingresp:
return &PingrespPacket{FixedHeader: FixedHeader{MessageType: Pingresp}}
}
return nil
}
// NewControlPacketWithHeader is used to create a new ControlPacket of the type
// specified within the FixedHeader that is passed to the function.
// The newly created ControlPacket is empty and a pointer is returned.
func NewControlPacketWithHeader(fh FixedHeader) (ControlPacket, error) {
switch fh.MessageType {
case Connect:
return &ConnectPacket{FixedHeader: fh}, nil
case Connack:
return &ConnackPacket{FixedHeader: fh}, nil
case Disconnect:
return &DisconnectPacket{FixedHeader: fh}, nil
case Publish:
return &PublishPacket{FixedHeader: fh}, nil
case Puback:
return &PubackPacket{FixedHeader: fh}, nil
case Pubrec:
return &PubrecPacket{FixedHeader: fh}, nil
case Pubrel:
return &PubrelPacket{FixedHeader: fh}, nil
case Pubcomp:
return &PubcompPacket{FixedHeader: fh}, nil
case Subscribe:
return &SubscribePacket{FixedHeader: fh}, nil
case Suback:
return &SubackPacket{FixedHeader: fh}, nil
case Unsubscribe:
return &UnsubscribePacket{FixedHeader: fh}, nil
case Unsuback:
return &UnsubackPacket{FixedHeader: fh}, nil
case Pingreq:
return &PingreqPacket{FixedHeader: fh}, nil
case Pingresp:
return &PingrespPacket{FixedHeader: fh}, nil
}
return nil, fmt.Errorf("unsupported packet type 0x%x", fh.MessageType)
}
// Details struct returned by the Details() function called on
// ControlPackets to present details of the Qos and MessageID
// of the ControlPacket
type Details struct {
Qos byte
MessageID uint16
}
// FixedHeader is a struct to hold the decoded information from
// the fixed header of an MQTT ControlPacket
type FixedHeader struct {
MessageType byte
Dup bool
Qos byte
Retain bool
RemainingLength int
}
func (fh FixedHeader) String() string {
return fmt.Sprintf("%s: dup: %t qos: %d retain: %t rLength: %d", PacketNames[fh.MessageType], fh.Dup, fh.Qos, fh.Retain, fh.RemainingLength)
}
func boolToByte(b bool) byte {
switch b {
case true:
return 1
default:
return 0
}
}
func (fh *FixedHeader) pack() bytes.Buffer {
var header bytes.Buffer
header.WriteByte(fh.MessageType<<4 | boolToByte(fh.Dup)<<3 | fh.Qos<<1 | boolToByte(fh.Retain))
header.Write(encodeLength(fh.RemainingLength))
return header
}
func (fh *FixedHeader) unpack(typeAndFlags byte, r io.Reader) error {
fh.MessageType = typeAndFlags >> 4
fh.Dup = (typeAndFlags>>3)&0x01 > 0
fh.Qos = (typeAndFlags >> 1) & 0x03
fh.Retain = typeAndFlags&0x01 > 0
var err error
fh.RemainingLength, err = decodeLength(r)
return err
}
func decodeByte(b io.Reader) (byte, error) {
num := make([]byte, 1)
_, err := b.Read(num)
if err != nil {
return 0, err
}
return num[0], nil
}
func decodeUint16(b io.Reader) (uint16, error) {
num := make([]byte, 2)
_, err := b.Read(num)
if err != nil {
return 0, err
}
return binary.BigEndian.Uint16(num), nil
}
func encodeUint16(num uint16) []byte {
bytesResult := make([]byte, 2)
binary.BigEndian.PutUint16(bytesResult, num)
return bytesResult
}
func encodeString(field string) []byte {
return encodeBytes([]byte(field))
}
func decodeString(b io.Reader) (string, error) {
buf, err := decodeBytes(b)
return string(buf), err
}
func decodeBytes(b io.Reader) ([]byte, error) {
fieldLength, err := decodeUint16(b)
if err != nil {
return nil, err
}
field := make([]byte, fieldLength)
_, err = b.Read(field)
if err != nil {
return nil, err
}
return field, nil
}
func encodeBytes(field []byte) []byte {
fieldLength := make([]byte, 2)
binary.BigEndian.PutUint16(fieldLength, uint16(len(field)))
return append(fieldLength, field...)
}
func encodeLength(length int) []byte {
var encLength []byte
for {
digit := byte(length % 128)
length /= 128
if length > 0 {
digit |= 0x80
}
encLength = append(encLength, digit)
if length == 0 {
break
}
}
return encLength
}
func decodeLength(r io.Reader) (int, error) {
var rLength uint32
var multiplier uint32
b := make([]byte, 1)
for multiplier < 27 { // fix: Infinite '(digit & 128) == 1' will cause the dead loop
_, err := io.ReadFull(r, b)
if err != nil {
return 0, err
}
digit := b[0]
rLength |= uint32(digit&127) << multiplier
if (digit & 128) == 0 {
break
}
multiplier += 7
}
return int(rLength), nil
}

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package packets
import (
"io"
)
// PingreqPacket is an internal representation of the fields of the
// Pingreq MQTT packet
type PingreqPacket struct {
FixedHeader
}
func (pr *PingreqPacket) String() string {
return pr.FixedHeader.String()
}
func (pr *PingreqPacket) Write(w io.Writer) error {
packet := pr.FixedHeader.pack()
_, err := packet.WriteTo(w)
return err
}
// Unpack decodes the details of a ControlPacket after the fixed
// header has been read
func (pr *PingreqPacket) Unpack(b io.Reader) error {
return nil
}
// Details returns a Details struct containing the Qos and
// MessageID of this ControlPacket
func (pr *PingreqPacket) Details() Details {
return Details{Qos: 0, MessageID: 0}
}

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package packets
import (
"io"
)
// PingrespPacket is an internal representation of the fields of the
// Pingresp MQTT packet
type PingrespPacket struct {
FixedHeader
}
func (pr *PingrespPacket) String() string {
return pr.FixedHeader.String()
}
func (pr *PingrespPacket) Write(w io.Writer) error {
packet := pr.FixedHeader.pack()
_, err := packet.WriteTo(w)
return err
}
// Unpack decodes the details of a ControlPacket after the fixed
// header has been read
func (pr *PingrespPacket) Unpack(b io.Reader) error {
return nil
}
// Details returns a Details struct containing the Qos and
// MessageID of this ControlPacket
func (pr *PingrespPacket) Details() Details {
return Details{Qos: 0, MessageID: 0}
}

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package packets
import (
"fmt"
"io"
)
// PubackPacket is an internal representation of the fields of the
// Puback MQTT packet
type PubackPacket struct {
FixedHeader
MessageID uint16
}
func (pa *PubackPacket) String() string {
return fmt.Sprintf("%s MessageID: %d", pa.FixedHeader, pa.MessageID)
}
func (pa *PubackPacket) Write(w io.Writer) error {
var err error
pa.FixedHeader.RemainingLength = 2
packet := pa.FixedHeader.pack()
packet.Write(encodeUint16(pa.MessageID))
_, err = packet.WriteTo(w)
return err
}
// Unpack decodes the details of a ControlPacket after the fixed
// header has been read
func (pa *PubackPacket) Unpack(b io.Reader) error {
var err error
pa.MessageID, err = decodeUint16(b)
return err
}
// Details returns a Details struct containing the Qos and
// MessageID of this ControlPacket
func (pa *PubackPacket) Details() Details {
return Details{Qos: pa.Qos, MessageID: pa.MessageID}
}

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package packets
import (
"fmt"
"io"
)
// PubcompPacket is an internal representation of the fields of the
// Pubcomp MQTT packet
type PubcompPacket struct {
FixedHeader
MessageID uint16
}
func (pc *PubcompPacket) String() string {
return fmt.Sprintf("%s MessageID: %d", pc.FixedHeader, pc.MessageID)
}
func (pc *PubcompPacket) Write(w io.Writer) error {
var err error
pc.FixedHeader.RemainingLength = 2
packet := pc.FixedHeader.pack()
packet.Write(encodeUint16(pc.MessageID))
_, err = packet.WriteTo(w)
return err
}
// Unpack decodes the details of a ControlPacket after the fixed
// header has been read
func (pc *PubcompPacket) Unpack(b io.Reader) error {
var err error
pc.MessageID, err = decodeUint16(b)
return err
}
// Details returns a Details struct containing the Qos and
// MessageID of this ControlPacket
func (pc *PubcompPacket) Details() Details {
return Details{Qos: pc.Qos, MessageID: pc.MessageID}
}

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package packets
import (
"bytes"
"fmt"
"io"
)
// PublishPacket is an internal representation of the fields of the
// Publish MQTT packet
type PublishPacket struct {
FixedHeader
TopicName string
MessageID uint16
Payload []byte
}
func (p *PublishPacket) String() string {
return fmt.Sprintf("%s topicName: %s MessageID: %d payload: %s", p.FixedHeader, p.TopicName, p.MessageID, string(p.Payload))
}
func (p *PublishPacket) Write(w io.Writer) error {
var body bytes.Buffer
var err error
body.Write(encodeString(p.TopicName))
if p.Qos > 0 {
body.Write(encodeUint16(p.MessageID))
}
p.FixedHeader.RemainingLength = body.Len() + len(p.Payload)
packet := p.FixedHeader.pack()
packet.Write(body.Bytes())
packet.Write(p.Payload)
_, err = w.Write(packet.Bytes())
return err
}
// Unpack decodes the details of a ControlPacket after the fixed
// header has been read
func (p *PublishPacket) Unpack(b io.Reader) error {
var payloadLength = p.FixedHeader.RemainingLength
var err error
p.TopicName, err = decodeString(b)
if err != nil {
return err
}
if p.Qos > 0 {
p.MessageID, err = decodeUint16(b)
if err != nil {
return err
}
payloadLength -= len(p.TopicName) + 4
} else {
payloadLength -= len(p.TopicName) + 2
}
if payloadLength < 0 {
return fmt.Errorf("error unpacking publish, payload length < 0")
}
p.Payload = make([]byte, payloadLength)
_, err = b.Read(p.Payload)
return err
}
// Copy creates a new PublishPacket with the same topic and payload
// but an empty fixed header, useful for when you want to deliver
// a message with different properties such as Qos but the same
// content
func (p *PublishPacket) Copy() *PublishPacket {
newP := NewControlPacket(Publish).(*PublishPacket)
newP.TopicName = p.TopicName
newP.Payload = p.Payload
return newP
}
// Details returns a Details struct containing the Qos and
// MessageID of this ControlPacket
func (p *PublishPacket) Details() Details {
return Details{Qos: p.Qos, MessageID: p.MessageID}
}

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package packets
import (
"fmt"
"io"
)
// PubrecPacket is an internal representation of the fields of the
// Pubrec MQTT packet
type PubrecPacket struct {
FixedHeader
MessageID uint16
}
func (pr *PubrecPacket) String() string {
return fmt.Sprintf("%s MessageID: %d", pr.FixedHeader, pr.MessageID)
}
func (pr *PubrecPacket) Write(w io.Writer) error {
var err error
pr.FixedHeader.RemainingLength = 2
packet := pr.FixedHeader.pack()
packet.Write(encodeUint16(pr.MessageID))
_, err = packet.WriteTo(w)
return err
}
// Unpack decodes the details of a ControlPacket after the fixed
// header has been read
func (pr *PubrecPacket) Unpack(b io.Reader) error {
var err error
pr.MessageID, err = decodeUint16(b)
return err
}
// Details returns a Details struct containing the Qos and
// MessageID of this ControlPacket
func (pr *PubrecPacket) Details() Details {
return Details{Qos: pr.Qos, MessageID: pr.MessageID}
}

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package packets
import (
"fmt"
"io"
)
// PubrelPacket is an internal representation of the fields of the
// Pubrel MQTT packet
type PubrelPacket struct {
FixedHeader
MessageID uint16
}
func (pr *PubrelPacket) String() string {
return fmt.Sprintf("%s MessageID: %d", pr.FixedHeader, pr.MessageID)
}
func (pr *PubrelPacket) Write(w io.Writer) error {
var err error
pr.FixedHeader.RemainingLength = 2
packet := pr.FixedHeader.pack()
packet.Write(encodeUint16(pr.MessageID))
_, err = packet.WriteTo(w)
return err
}
// Unpack decodes the details of a ControlPacket after the fixed
// header has been read
func (pr *PubrelPacket) Unpack(b io.Reader) error {
var err error
pr.MessageID, err = decodeUint16(b)
return err
}
// Details returns a Details struct containing the Qos and
// MessageID of this ControlPacket
func (pr *PubrelPacket) Details() Details {
return Details{Qos: pr.Qos, MessageID: pr.MessageID}
}

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package packets
import (
"bytes"
"fmt"
"io"
)
// SubackPacket is an internal representation of the fields of the
// Suback MQTT packet
type SubackPacket struct {
FixedHeader
MessageID uint16
ReturnCodes []byte
}
func (sa *SubackPacket) String() string {
return fmt.Sprintf("%s MessageID: %d", sa.FixedHeader, sa.MessageID)
}
func (sa *SubackPacket) Write(w io.Writer) error {
var body bytes.Buffer
var err error
body.Write(encodeUint16(sa.MessageID))
body.Write(sa.ReturnCodes)
sa.FixedHeader.RemainingLength = body.Len()
packet := sa.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 (sa *SubackPacket) Unpack(b io.Reader) error {
var qosBuffer bytes.Buffer
var err error
sa.MessageID, err = decodeUint16(b)
if err != nil {
return err
}
_, err = qosBuffer.ReadFrom(b)
if err != nil {
return err
}
sa.ReturnCodes = qosBuffer.Bytes()
return nil
}
// Details returns a Details struct containing the Qos and
// MessageID of this ControlPacket
func (sa *SubackPacket) Details() Details {
return Details{Qos: 0, MessageID: sa.MessageID}
}

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@@ -0,0 +1,69 @@
package packets
import (
"bytes"
"fmt"
"io"
)
// SubscribePacket is an internal representation of the fields of the
// Subscribe MQTT packet
type SubscribePacket struct {
FixedHeader
MessageID uint16
Topics []string
Qoss []byte
}
func (s *SubscribePacket) String() string {
return fmt.Sprintf("%s MessageID: %d topics: %s", s.FixedHeader, s.MessageID, s.Topics)
}
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) error {
var err error
s.MessageID, err = decodeUint16(b)
if err != nil {
return err
}
payloadLength := s.FixedHeader.RemainingLength - 2
for payloadLength > 0 {
topic, err := decodeString(b)
if err != nil {
return err
}
s.Topics = append(s.Topics, topic)
qos, err := decodeByte(b)
if err != nil {
return err
}
s.Qoss = append(s.Qoss, qos)
payloadLength -= 2 + len(topic) + 1 // 2 bytes of string length, plus string, plus 1 byte for Qos
}
return nil
}
// 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}
}

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@@ -0,0 +1,42 @@
package packets
import (
"fmt"
"io"
)
// UnsubackPacket is an internal representation of the fields of the
// Unsuback MQTT packet
type UnsubackPacket struct {
FixedHeader
MessageID uint16
}
func (ua *UnsubackPacket) String() string {
return fmt.Sprintf("%s MessageID: %d", ua.FixedHeader, ua.MessageID)
}
func (ua *UnsubackPacket) Write(w io.Writer) error {
var err error
ua.FixedHeader.RemainingLength = 2
packet := ua.FixedHeader.pack()
packet.Write(encodeUint16(ua.MessageID))
_, err = packet.WriteTo(w)
return err
}
// Unpack decodes the details of a ControlPacket after the fixed
// header has been read
func (ua *UnsubackPacket) Unpack(b io.Reader) error {
var err error
ua.MessageID, err = decodeUint16(b)
return err
}
// Details returns a Details struct containing the Qos and
// MessageID of this ControlPacket
func (ua *UnsubackPacket) Details() Details {
return Details{Qos: 0, MessageID: ua.MessageID}
}

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@@ -0,0 +1,56 @@
package packets
import (
"bytes"
"fmt"
"io"
)
// UnsubscribePacket is an internal representation of the fields of the
// Unsubscribe MQTT packet
type UnsubscribePacket struct {
FixedHeader
MessageID uint16
Topics []string
}
func (u *UnsubscribePacket) String() string {
return fmt.Sprintf("%s MessageID: %d", u.FixedHeader, u.MessageID)
}
func (u *UnsubscribePacket) Write(w io.Writer) error {
var body bytes.Buffer
var err error
body.Write(encodeUint16(u.MessageID))
for _, topic := range u.Topics {
body.Write(encodeString(topic))
}
u.FixedHeader.RemainingLength = body.Len()
packet := u.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 (u *UnsubscribePacket) Unpack(b io.Reader) error {
var err error
u.MessageID, err = decodeUint16(b)
if err != nil {
return err
}
for topic, err := decodeString(b); err == nil && topic != ""; topic, err = decodeString(b) {
u.Topics = append(u.Topics, topic)
}
return err
}
// Details returns a Details struct containing the Qos and
// MessageID of this ControlPacket
func (u *UnsubscribePacket) Details() Details {
return Details{Qos: 1, MessageID: u.MessageID}
}