packet

package
v0.4.0 Latest Latest
Warning

This package is not in the latest version of its module.

 Go to latest Published: Dec 28, 2017 License: Apache-2.0 Imports: 7 Imported by: 0

Documentation

Overview

Package packet implements functionality for encoding and decoding MQTT packets.

Example 
/* Packet Encoding */

// Create new packet.
pkt1 := NewConnectPacket()
pkt1.Username = "gomqtt"
pkt1.Password = "amazing!"

// Allocate buffer.
buf := make([]byte, pkt1.Len())

// Encode the packet.
if _, err := pkt1.Encode(buf); err != nil {
	panic(err) // error while encoding
}

/* Packet Decoding */

// Detect packet.
l, mt := DetectPacket(buf)

// Check length
if l == 0 {
	return // buffer not complete yet
}

// Create packet.
pkt2, err := mt.New()
if err != nil {
	panic(err) // packet type is invalid
}

// Decode packet.
_, err = pkt2.Decode(buf)
if err != nil {
	panic(err) // there was an error while decoding
}

switch pkt2.Type() {
case CONNECT:
	c := pkt2.(*ConnectPacket)
	fmt.Println(c.Username)
	fmt.Println(c.Password)
}

Output:

gomqtt
amazing!

Index

Examples

Constants

View Source 
const (
	Version311 byte = 4
	Version31  byte = 3
)

The supported MQTT versions.

View Source 
const (
	// QOSAtMostOnce defines that the message is delivered at most once, or it
	// may not be delivered at all.
	QOSAtMostOnce byte = iota

	// QOSAtLeastOnce defines that the message is always delivered at least once.
	QOSAtLeastOnce

	// QOSExactlyOnce defines that the message is always delivered exactly once.
	QOSExactlyOnce

	// QOSFailure indicates that there has been an error while subscribing
	// to a specific topic.
	QOSFailure = 0x80
)

Variables

View Source 
var ErrDetectionOverflow = errors.New("detection overflow")

ErrDetectionOverflow is returned by the Decoder if the next packet couldn't be detect from the initial header bytes.

View Source 
var ErrReadLimitExceeded = errors.New("read limit exceeded")

ErrReadLimitExceeded can be returned during a Receive if the connection exceeded its read limit.

Note: this error is wrapped in an Error with a NetworkError code.

Functions

func Fuzz 

func Fuzz(data []byte) int

Fuzz is a basic fuzzing test that works with https://github.com/dvyukov/go-fuzz: 

$ go-fuzz-build github.com/gomqtt/packet
$ go-fuzz -bin=./packet-fuzz.zip -workdir=./fuzz

Types

type ConnackCode 

type ConnackCode uint8

The ConnackCode represents the return code in a ConnackPacket. 

const (
	ConnectionAccepted ConnackCode = iota
	ErrInvalidProtocolVersion
	ErrIdentifierRejected
	ErrServerUnavailable
	ErrBadUsernameOrPassword
	ErrNotAuthorized
)

All available ConnackCodes.

func (ConnackCode) Error 

func (cc ConnackCode) Error() string

Error returns the corresponding error string for the ConnackCode.

func (ConnackCode) Valid 

func (cc ConnackCode) Valid() bool

Valid checks if the ConnackCode is valid.

type ConnackPacket 

type ConnackPacket struct {
	// The SessionPresent flag enables a client to establish whether the
	// client and server have a consistent view about whether there is already
	// stored session state.
	SessionPresent bool

	// If a well formed ConnectPacket is received by the server, but the server
	// is unable to process it for some reason, then the server should attempt
	// to send a ConnackPacket containing a non-zero ReturnCode.
	ReturnCode ConnackCode
}

A ConnackPacket is sent by the server in response to a ConnectPacket received from a client.

func NewConnackPacket 

func NewConnackPacket() *ConnackPacket

NewConnackPacket creates a new ConnackPacket.

func (*ConnackPacket) Decode 

func (cp *ConnackPacket) Decode(src []byte) (int, error)

Decode reads from the byte slice argument. It returns the total number of bytes decoded, and whether there have been any errors during the process.

func (*ConnackPacket) Encode 

func (cp *ConnackPacket) Encode(dst []byte) (int, error)

Encode writes the packet bytes into the byte slice from the argument. It returns the number of bytes encoded and whether there's any errors along the way. If there is an error, the byte slice should be considered invalid.

func (*ConnackPacket) Len 

func (cp *ConnackPacket) Len() int

Len returns the byte length of the encoded packet.

func (*ConnackPacket) String 

func (cp *ConnackPacket) String() string

String returns a string representation of the packet.

func (*ConnackPacket) Type 

func (cp *ConnackPacket) Type() Type

Type returns the packets type.

type ConnectPacket 

type ConnectPacket struct {
	// The clients client id.
	ClientID string

	// The keep alive value.
	KeepAlive uint16

	// The authentication username.
	Username string

	// The authentication password.
	Password string

	// The clean session flag.
	CleanSession bool

	// The will message.
	Will *Message

	// The MQTT version 3 or 4 (defaults to 4 when 0).
	Version byte
}

A ConnectPacket is sent by a client to the server after a network connection has been established.

func NewConnectPacket 

func NewConnectPacket() *ConnectPacket

NewConnectPacket creates a new ConnectPacket.

func (*ConnectPacket) Decode 

func (cp *ConnectPacket) Decode(src []byte) (int, error)

Decode reads from the byte slice argument. It returns the total number of bytes decoded, and whether there have been any errors during the process.

func (*ConnectPacket) Encode 

func (cp *ConnectPacket) Encode(dst []byte) (int, error)

Encode writes the packet bytes into the byte slice from the argument. It returns the number of bytes encoded and whether there's any errors along the way. If there is an error, the byte slice should be considered invalid.

func (*ConnectPacket) Len 

func (cp *ConnectPacket) Len() int

Len returns the byte length of the encoded packet.

func (*ConnectPacket) String 

func (cp *ConnectPacket) String() string

String returns a string representation of the packet.

func (*ConnectPacket) Type 

func (cp *ConnectPacket) Type() Type

Type returns the packets type.

type Decoder 

type Decoder struct {
	Limit int64
	// contains filtered or unexported fields
}

A Decoder wraps a Reader and continuously decodes packets.

func NewDecoder 

func NewDecoder(reader io.Reader) *Decoder

NewDecoder returns a new Decoder.

func (*Decoder) Read 

func (d *Decoder) Read() (GenericPacket, error)

Read reads the next packet from the buffered reader.

type DisconnectPacket 

type DisconnectPacket struct{}

A DisconnectPacket is sent from the client to the server. It indicates that the client is disconnecting cleanly.

func NewDisconnectPacket 

func NewDisconnectPacket() *DisconnectPacket

NewDisconnectPacket creates a new DisconnectPacket.

func (*DisconnectPacket) Decode 

func (dp *DisconnectPacket) Decode(src []byte) (int, error)

Decode reads from the byte slice argument. It returns the total number of bytes decoded, and whether there have been any errors during the process.

func (*DisconnectPacket) Encode 

func (dp *DisconnectPacket) Encode(dst []byte) (int, error)

Encode writes the packet bytes into the byte slice from the argument. It returns the number of bytes encoded and whether there's any errors along the way. If there is an error, the byte slice should be considered invalid.

func (*DisconnectPacket) Len 

func (dp *DisconnectPacket) Len() int

Len returns the byte length of the encoded packet.

func (*DisconnectPacket) String 

func (dp *DisconnectPacket) String() string

String returns a string representation of the packet.

func (*DisconnectPacket) Type 

func (dp *DisconnectPacket) Type() Type

Type returns the packets type.

type Encoder 

type Encoder struct {
	// contains filtered or unexported fields
}

An Encoder wraps a Writer and continuously encodes packets.

func NewEncoder 

func NewEncoder(writer io.Writer) *Encoder

NewEncoder creates a new Encoder.

func (*Encoder) Flush 

func (e *Encoder) Flush() error

Flush flushes the writer buffer.

func (*Encoder) Write 

func (e *Encoder) Write(pkt GenericPacket) error

Write encodes and writes the passed packet to the write buffer.

type GenericPacket added in v0.2.0 

type GenericPacket interface {
	// Type returns the packets type.
	Type() Type

	// Len returns the byte length of the encoded packet.
	Len() int

	// Decode reads from the byte slice argument. It returns the total number of
	// bytes decoded, and whether there have been any errors during the process.
	Decode(src []byte) (int, error)

	// Encode writes the packet bytes into the byte slice from the argument. It
	// returns the number of bytes encoded and whether there's any errors along
	// the way. If there is an error, the byte slice should be considered invalid.
	Encode(dst []byte) (int, error)

	// String returns a string representation of the packet.
	String() string
}

A GenericPacket is an MQTT control packet that can be encoded to a buffer or decoded from a buffer.

type ID added in v0.2.0 

type ID uint16

ID is the type used to store packet ids.

func GetID added in v0.2.0 

func GetID(packet GenericPacket) (ID, bool)

GetID checks the packets type and returns its ID and true, or if it does not have a ID, zero and false.

type Message 

type Message struct {
	// The Topic of the message.
	Topic string

	// The Payload of the message.
	Payload []byte

	// The QOS indicates the level of assurance for delivery.
	QOS byte

	// If the Retain flag is set to true, the server must store the message,
	// so that it can be delivered to future subscribers whose subscriptions
	// match its topic name.
	Retain bool
}

A Message bundles data that is published between brokers and clients.

func (Message) Copy 

func (m Message) Copy() *Message

Copy returns a copy of the message.

func (*Message) String 

func (m *Message) String() string

String returns a string representation of the message.

type PingreqPacket 

type PingreqPacket struct{}

A PingreqPacket is sent from a client to the server.

func NewPingreqPacket 

func NewPingreqPacket() *PingreqPacket

NewPingreqPacket creates a new PingreqPacket.

func (*PingreqPacket) Decode 

func (pp *PingreqPacket) Decode(src []byte) (int, error)

Decode reads from the byte slice argument. It returns the total number of bytes decoded, and whether there have been any errors during the process.

func (*PingreqPacket) Encode 

func (pp *PingreqPacket) Encode(dst []byte) (int, error)

Encode writes the packet bytes into the byte slice from the argument. It returns the number of bytes encoded and whether there's any errors along the way. If there is an error, the byte slice should be considered invalid.

func (*PingreqPacket) Len 

func (pp *PingreqPacket) Len() int

Len returns the byte length of the encoded packet.

func (*PingreqPacket) String 

func (pp *PingreqPacket) String() string

String returns a string representation of the packet.

func (*PingreqPacket) Type 

func (pp *PingreqPacket) Type() Type

Type returns the packets type.

type PingrespPacket 

type PingrespPacket struct{}

A PingrespPacket is sent by the server to the client in response to a PingreqPacket. It indicates that the server is alive.

func NewPingrespPacket 

func NewPingrespPacket() *PingrespPacket

NewPingrespPacket creates a new PingrespPacket.

func (*PingrespPacket) Decode 

func (pp *PingrespPacket) Decode(src []byte) (int, error)

Decode reads from the byte slice argument. It returns the total number of bytes decoded, and whether there have been any errors during the process.

func (*PingrespPacket) Encode 

func (pp *PingrespPacket) Encode(dst []byte) (int, error)

Encode writes the packet bytes into the byte slice from the argument. It returns the number of bytes encoded and whether there's any errors along the way. If there is an error, the byte slice should be considered invalid.

func (*PingrespPacket) Len 

func (pp *PingrespPacket) Len() int

Len returns the byte length of the encoded packet.

func (*PingrespPacket) String 

func (pp *PingrespPacket) String() string

String returns a string representation of the packet.

func (*PingrespPacket) Type 

func (pp *PingrespPacket) Type() Type

Type returns the packets type.

type PubackPacket 

type PubackPacket struct {
	// The packet identifier.
	ID ID
}

A PubackPacket is the response to a PublishPacket with QOS level 1.

func NewPubackPacket 

func NewPubackPacket() *PubackPacket

NewPubackPacket creates a new PubackPacket.

func (*PubackPacket) Decode 

func (pp *PubackPacket) Decode(src []byte) (int, error)

Decode reads from the byte slice argument. It returns the total number of bytes decoded, and whether there have been any errors during the process.

func (*PubackPacket) Encode 

func (pp *PubackPacket) Encode(dst []byte) (int, error)

Encode writes the packet bytes into the byte slice from the argument. It returns the number of bytes encoded and whether there's any errors along the way. If there is an error, the byte slice should be considered invalid.

func (*PubackPacket) Len 

func (pp *PubackPacket) Len() int

Len returns the byte length of the encoded packet.

func (*PubackPacket) String 

func (pp *PubackPacket) String() string

String returns a string representation of the packet.

func (*PubackPacket) Type 

func (pp *PubackPacket) Type() Type

Type returns the packets type.

type PubcompPacket 

type PubcompPacket struct {
	// The packet identifier.
	ID ID
}

A PubcompPacket is the response to a PubrelPacket. It is the fourth and final packet of the QOS 2 protocol exchange.

func NewPubcompPacket 

func NewPubcompPacket() *PubcompPacket

NewPubcompPacket creates a new PubcompPacket.

func (*PubcompPacket) Decode 

func (pp *PubcompPacket) Decode(src []byte) (int, error)

Decode reads from the byte slice argument. It returns the total number of bytes decoded, and whether there have been any errors during the process.

func (*PubcompPacket) Encode 

func (pp *PubcompPacket) Encode(dst []byte) (int, error)

Encode writes the packet bytes into the byte slice from the argument. It returns the number of bytes encoded and whether there's any errors along the way. If there is an error, the byte slice should be considered invalid.

func (*PubcompPacket) Len 

func (pp *PubcompPacket) Len() int

Len returns the byte length of the encoded packet.

func (*PubcompPacket) String 

func (pp *PubcompPacket) String() string

String returns a string representation of the packet.

func (*PubcompPacket) Type 

func (pp *PubcompPacket) Type() Type

Type returns the packets type.

type PublishPacket 

type PublishPacket struct {
	// The message to publish.
	Message Message

	// If the Dup flag is set to false, it indicates that this is the first
	// occasion that the client or server has attempted to send this
	// PublishPacket. If the dup flag is set to true, it indicates that this
	// might be re-delivery of an earlier attempt to send the packet.
	Dup bool

	// The packet identifier.
	ID ID
}

A PublishPacket is sent from a client to a server or from server to a client to transport an application message.

func NewPublishPacket 

func NewPublishPacket() *PublishPacket

NewPublishPacket creates a new PublishPacket.

func (*PublishPacket) Decode 

func (pp *PublishPacket) Decode(src []byte) (int, error)

Decode reads from the byte slice argument. It returns the total number of bytes decoded, and whether there have been any errors during the process.

func (*PublishPacket) Encode 

func (pp *PublishPacket) Encode(dst []byte) (int, error)

Encode writes the packet bytes into the byte slice from the argument. It returns the number of bytes encoded and whether there's any errors along the way. If there is an error, the byte slice should be considered invalid.

func (*PublishPacket) Len 

func (pp *PublishPacket) Len() int

Len returns the byte length of the encoded packet.

func (*PublishPacket) String 

func (pp *PublishPacket) String() string

String returns a string representation of the packet.

func (*PublishPacket) Type 

func (pp *PublishPacket) Type() Type

Type returns the packets type.

type PubrecPacket 

type PubrecPacket struct {
	// Shared packet identifier.
	ID ID
}

A PubrecPacket is the response to a PublishPacket with QOS 2. It is the second packet of the QOS 2 protocol exchange.

func NewPubrecPacket 

func NewPubrecPacket() *PubrecPacket

NewPubrecPacket creates a new PubrecPacket.

func (*PubrecPacket) Decode 

func (pp *PubrecPacket) Decode(src []byte) (int, error)

Decode reads from the byte slice argument. It returns the total number of bytes decoded, and whether there have been any errors during the process.

func (*PubrecPacket) Encode 

func (pp *PubrecPacket) Encode(dst []byte) (int, error)

Encode writes the packet bytes into the byte slice from the argument. It returns the number of bytes encoded and whether there's any errors along the way. If there is an error, the byte slice should be considered invalid.

func (*PubrecPacket) Len 

func (pp *PubrecPacket) Len() int

Len returns the byte length of the encoded packet.

func (*PubrecPacket) String 

func (pp *PubrecPacket) String() string

String returns a string representation of the packet.

func (*PubrecPacket) Type 

func (pp *PubrecPacket) Type() Type

Type returns the packets type.

type PubrelPacket 

type PubrelPacket struct {
	// Shared packet identifier.
	ID ID
}

A PubrelPacket is the response to a PubrecPacket. It is the third packet of the QOS 2 protocol exchange.

func NewPubrelPacket 

func NewPubrelPacket() *PubrelPacket

NewPubrelPacket creates a new PubrelPacket.

func (*PubrelPacket) Decode 

func (pp *PubrelPacket) Decode(src []byte) (int, error)

Decode reads from the byte slice argument. It returns the total number of bytes decoded, and whether there have been any errors during the process.

func (*PubrelPacket) Encode 

func (pp *PubrelPacket) Encode(dst []byte) (int, error)

Encode writes the packet bytes into the byte slice from the argument. It returns the number of bytes encoded and whether there's any errors along the way. If there is an error, the byte slice should be considered invalid.

func (*PubrelPacket) Len 

func (pp *PubrelPacket) Len() int

Len returns the byte length of the encoded packet.

func (*PubrelPacket) String 

func (pp *PubrelPacket) String() string

String returns a string representation of the packet.

func (*PubrelPacket) Type 

func (pp *PubrelPacket) Type() Type

Type returns the packets type.

type Stream 

type Stream struct {
	Decoder
	Encoder
}

A Stream combines an Encoder and Decoder

func NewStream 

func NewStream(reader io.Reader, writer io.Writer) *Stream

NewStream creates a new Stream.

type SubackPacket 

type SubackPacket struct {
	// The granted QOS levels for the requested subscriptions.
	ReturnCodes []uint8

	// The packet identifier.
	ID ID
}

A SubackPacket is sent by the server to the client to confirm receipt and processing of a SubscribePacket. The SubackPacket contains a list of return codes, that specify the maximum QOS levels that have been granted.

func NewSubackPacket 

func NewSubackPacket() *SubackPacket

NewSubackPacket creates a new SubackPacket.

func (*SubackPacket) Decode 

func (sp *SubackPacket) Decode(src []byte) (int, error)

Decode reads from the byte slice argument. It returns the total number of bytes decoded, and whether there have been any errors during the process.

func (*SubackPacket) Encode 

func (sp *SubackPacket) Encode(dst []byte) (int, error)

Encode writes the packet bytes into the byte slice from the argument. It returns the number of bytes encoded and whether there's any errors along the way. If there is an error, the byte slice should be considered invalid.

func (*SubackPacket) Len 

func (sp *SubackPacket) Len() int

Len returns the byte length of the encoded packet.

func (*SubackPacket) String 

func (sp *SubackPacket) String() string

String returns a string representation of the packet.

func (*SubackPacket) Type 

func (sp *SubackPacket) Type() Type

Type returns the packets type.

type SubscribePacket 

type SubscribePacket struct {
	// The subscriptions.
	Subscriptions []Subscription

	// The packet identifier.
	ID ID
}

A SubscribePacket is sent from the client to the server to create one or more Subscriptions. The server will forward application messages that match these subscriptions using PublishPackets.

func NewSubscribePacket 

func NewSubscribePacket() *SubscribePacket

NewSubscribePacket creates a new SUBSCRIBE packet.

func (*SubscribePacket) Decode 

func (sp *SubscribePacket) Decode(src []byte) (int, error)

Decode reads from the byte slice argument. It returns the total number of bytes decoded, and whether there have been any errors during the process.

func (*SubscribePacket) Encode 

func (sp *SubscribePacket) Encode(dst []byte) (int, error)

Encode writes the packet bytes into the byte slice from the argument. It returns the number of bytes encoded and whether there's any errors along the way. If there is an error, the byte slice should be considered invalid.

func (*SubscribePacket) Len 

func (sp *SubscribePacket) Len() int

Len returns the byte length of the encoded packet.

func (*SubscribePacket) String 

func (sp *SubscribePacket) String() string

String returns a string representation of the packet.

func (*SubscribePacket) Type 

func (sp *SubscribePacket) Type() Type

Type returns the packets type.

type Subscription 

type Subscription struct {
	// The topic to subscribe.
	Topic string

	// The requested maximum QOS level.
	QOS uint8
}

A Subscription is a single subscription in a SubscribePacket.

func (*Subscription) String 

func (s *Subscription) String() string

type Type 

type Type byte

Type represents the MQTT packet types. 

const (
	CONNECT Type
	CONNACK
	PUBLISH
	PUBACK
	PUBREC
	PUBREL
	PUBCOMP
	SUBSCRIBE
	SUBACK
	UNSUBSCRIBE
	UNSUBACK
	PINGREQ
	PINGRESP
	DISCONNECT
)

All packet types.

func DetectPacket 

func DetectPacket(src []byte) (int, Type)

DetectPacket tries to detect the next packet in a buffer. It returns a length greater than zero if the packet has been detected as well as its Type.

func (Type) New 

func (t Type) New() (GenericPacket, error)

New creates a new packet based on the type. It is a shortcut to call one of the New*Packet functions. An error is returned if the type is invalid.

func (Type) String 

func (t Type) String() string

String returns the type as a string.

func (Type) Valid 

func (t Type) Valid() bool

Valid returns a boolean indicating whether the type is valid or not.

type UnsubackPacket 

type UnsubackPacket struct {
	// Shared packet identifier.
	ID ID
}

An UnsubackPacket is sent by the server to the client to confirm receipt of an UnsubscribePacket.

func NewUnsubackPacket 

func NewUnsubackPacket() *UnsubackPacket

NewUnsubackPacket creates a new UnsubackPacket.

func (*UnsubackPacket) Decode 

func (up *UnsubackPacket) Decode(src []byte) (int, error)

Decode reads from the byte slice argument. It returns the total number of bytes decoded, and whether there have been any errors during the process.

func (*UnsubackPacket) Encode 

func (up *UnsubackPacket) Encode(dst []byte) (int, error)

Encode writes the packet bytes into the byte slice from the argument. It returns the number of bytes encoded and whether there's any errors along the way. If there is an error, the byte slice should be considered invalid.

func (*UnsubackPacket) Len 

func (up *UnsubackPacket) Len() int

Len returns the byte length of the encoded packet.

func (*UnsubackPacket) String 

func (up *UnsubackPacket) String() string

String returns a string representation of the packet.

func (*UnsubackPacket) Type 

func (up *UnsubackPacket) Type() Type

Type returns the packets type.

type UnsubscribePacket 

type UnsubscribePacket struct {
	// The topics to unsubscribe from.
	Topics []string

	// The packet identifier.
	ID ID
}

An UnsubscribePacket is sent by the client to the server.

func NewUnsubscribePacket 

func NewUnsubscribePacket() *UnsubscribePacket

NewUnsubscribePacket creates a new UnsubscribePacket.

func (*UnsubscribePacket) Decode 

func (up *UnsubscribePacket) Decode(src []byte) (int, error)

Decode reads from the byte slice argument. It returns the total number of bytes decoded, and whether there have been any errors during the process.

func (*UnsubscribePacket) Encode 

func (up *UnsubscribePacket) Encode(dst []byte) (int, error)

Encode writes the packet bytes into the byte slice from the argument. It returns the number of bytes encoded and whether there's any errors along the way. If there is an error, the byte slice should be considered invalid.

func (*UnsubscribePacket) Len 

func (up *UnsubscribePacket) Len() int

Len returns the byte length of the encoded packet.

func (*UnsubscribePacket) String 

func (up *UnsubscribePacket) String() string

String returns a string representation of the packet.

func (*UnsubscribePacket) Type 

func (up *UnsubscribePacket) Type() Type

Type returns the packets type.

Source Files

View all Source files

Jump to

Keyboard shortcuts

? : This menu
/ : Search site
f or F : Jump to
y or Y : Canonical URL
go.dev uses cookies from Google to deliver and enhance the quality of its services and to analyze traffic. Learn more.