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publish.go
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publish.go
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// Copyright (c) 2014 The VolantMQ Authors. All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package packet
import "time"
// Publish A PUBLISH Control Packet is sent from a Client to a Server or from Server to a Client
// to transport an Application Message.
type Publish struct {
header
payload []byte
topic string
publishID uintptr
expireAt *time.Time
}
var _ Provider = (*Publish)(nil)
func newPublish() *Publish {
return &Publish{
expireAt: nil,
publishID: 0,
}
}
// SetExpiry time object
func (msg *Publish) SetExpiry(tm time.Time) {
msg.expireAt = &tm
}
// GetExpiry time object
func (msg *Publish) GetExpiry() *time.Time {
return msg.expireAt
}
// Expired check if packet has elapsed it's time or not
// if not expirable returns false
func (msg *Publish) Expired(set bool) bool {
expired := false
if msg.expireAt != nil {
now := time.Now()
if df := uint32(msg.expireAt.Sub(now) / time.Second); msg.expireAt.After(now) && df > 0 {
if set && msg.version >= ProtocolV50 {
// TODO(troian): check error
msg.properties.Set(msg.mType, PropertyPublicationExpiry, df) // nolint: errcheck
}
} else {
expired = true
}
}
return expired
}
// Clone packet
// qos, topic, payload, retain and properties
func (msg *Publish) Clone(v ProtocolVersion) (*Publish, error) {
// message version should be same as session as encode/decode depends on it
_pkt, _ := New(msg.version, PUBLISH)
pkt, _ := _pkt.(*Publish)
// [MQTT-3.3.1-9]
// [MQTT-3.3.1-3]
pkt.Set(msg.topic, msg.Payload(), msg.QoS(), msg.Retain(), false) // nolint: errcheck
// clone expiration setting with no matter of version as message should not be delivered to V3 brokers
// when it expired
pkt.expireAt = msg.expireAt
if msg.version == ProtocolV50 && v == ProtocolV50 {
// [MQTT-3.3.2-4] forward Payload Format
if prop, ok := msg.properties.properties[PropertyPayloadFormat]; ok {
if err := pkt.properties.Set(msg.mType, PropertyPayloadFormat, prop); err != nil {
return nil, err
}
}
// [MQTT-1892 3.3.2-15] forward Response Topic
if prop, ok := msg.properties.properties[PropertyResponseTopic]; ok {
if err := pkt.properties.Set(msg.mType, PropertyResponseTopic, prop); err != nil {
return nil, err
}
}
// [MQTT-1908 3.3.2-16] forward Correlation Data
if prop, ok := msg.properties.properties[PropertyCorrelationData]; ok {
if err := pkt.properties.Set(msg.mType, PropertyCorrelationData, prop); err != nil {
return nil, err
}
}
// [MQTT-3.3.2-17] forward User Property
if prop, ok := msg.properties.properties[PropertyUserProperty]; ok {
if err := pkt.properties.Set(msg.mType, PropertyUserProperty, prop); err != nil {
return nil, err
}
}
// [MQTT-3.3.2-20] forward Content Type
if prop, ok := msg.properties.properties[PropertyContentType]; ok {
if err := pkt.properties.Set(msg.mType, PropertyContentType, prop); err != nil {
return nil, err
}
}
}
return pkt, nil
}
// PublishID get publish ID to check No Local
func (msg *Publish) PublishID() uintptr {
return msg.publishID
}
// SetPublishID internally used publish id to allow No Local option
func (msg *Publish) SetPublishID(id uintptr) {
msg.publishID = id
}
// Set topic/payload/qos/retained/bool
func (msg *Publish) Set(t string, p []byte, q QosType, r bool, d bool) error {
if !ValidTopic(t) {
return ErrInvalidTopic
}
if !q.IsValid() {
return ErrInvalidQoS
}
msg.mFlags &= ^maskPublishFlagQoS
msg.mFlags |= byte(q) << 1
msg.topic = t
msg.payload = p
if d {
msg.mFlags |= maskPublishFlagDup
} else {
msg.mFlags &= ^maskPublishFlagDup
}
if r {
msg.mFlags |= maskPublishFlagRetain
} else {
msg.mFlags &= ^maskPublishFlagRetain
}
return nil
}
// Dup returns the value specifying the duplicate delivery of a PUBLISH Control Packet.
// If the DUP flag is set to 0, it indicates that this is the first occasion that the
// Client or Server has attempted to send this MQTT PUBLISH Packet. If the DUP flag is
// set to 1, it indicates that this might be re-delivery of an earlier attempt to send
// the Packet.
func (msg *Publish) Dup() bool {
return (msg.mFlags & maskPublishFlagDup) != 0
}
// SetDup sets the value specifying the duplicate delivery of a PUBLISH Control Packet.
func (msg *Publish) SetDup(v bool) {
if v {
msg.mFlags |= maskPublishFlagDup // 0x8 // 00001000
} else {
msg.mFlags &= ^maskPublishFlagDup // 247 // 11110111
}
}
// Retain returns the value of the RETAIN flag. This flag is only used on the PUBLISH
// Packet. If the RETAIN flag is set to 1, in a PUBLISH Packet sent by a Client to a
// Server, the Server MUST store the Application Message and its QoS, so that it can be
// delivered to future subscribers whose subscriptions match its topic name.
func (msg *Publish) Retain() bool {
return (msg.mFlags & maskPublishFlagRetain) != 0
}
// SetRetain sets the value of the RETAIN flag.
func (msg *Publish) SetRetain(v bool) {
if v {
msg.mFlags |= maskPublishFlagRetain
} else {
msg.mFlags &= ^maskPublishFlagRetain
}
}
// QoS returns the field that indicates the level of assurance for delivery of an
// Application Message. The values are QoS0, QoS1 and QoS2.
func (msg *Publish) QoS() QosType {
return QosType((msg.mFlags & maskPublishFlagQoS) >> offsetPublishFlagQoS)
}
// SetQoS sets the field that indicates the level of assurance for delivery of an
// Application Message. The values are QoS0, QoS1 and QoS2.
// An error is returned if the value is not one of these.
func (msg *Publish) SetQoS(v QosType) error {
if !v.IsValid() {
return ErrInvalidQoS
}
msg.mFlags &= ^maskPublishFlagQoS
msg.mFlags |= byte(v) << 1
return nil
}
// Topic returns the the topic name that identifies the information channel to which
// payload data is published.
func (msg *Publish) Topic() string {
return msg.topic
}
// SetTopic sets the the topic name that identifies the information channel to which
// payload data is published. An error is returned if ValidTopic() is falbase.
func (msg *Publish) SetTopic(v string) error {
if (msg.version < ProtocolV50 && len(v) == 0) || !ValidTopic(v) {
return ErrInvalidTopic
}
msg.topic = v
return nil
}
// Payload returns the application message that's part of the PUBLISH message.
func (msg *Publish) Payload() []byte {
return msg.payload
}
// SetPayload sets the application message that's part of the PUBLISH message.
func (msg *Publish) SetPayload(v []byte) {
msg.payload = v
}
// SetPacketID sets the ID of the packet.
func (msg *Publish) SetPacketID(v IDType) {
msg.setPacketID(v)
}
func (msg *Publish) decodeMessage(from []byte) (int, error) {
var err error
var n int
var buf []byte
offset := 0
if !msg.QoS().IsValid() {
var rejectCode ReasonCode
if msg.version == ProtocolV50 {
rejectCode = CodeProtocolError
} else {
rejectCode = CodeRefusedServerUnavailable
}
return offset, rejectCode
}
// [MQTT-3.3.1-2]
if msg.QoS() == QoS0 && msg.Dup() {
var rejectCode ReasonCode
if msg.version == ProtocolV50 {
rejectCode = CodeProtocolError
} else {
rejectCode = CodeRefusedServerUnavailable
}
return offset, rejectCode
}
// [MQTT-3.3.2.1]
buf, n, err = ReadLPBytes(from[offset:])
offset += n
if err != nil {
return offset, err
}
if len(buf) == 0 && msg.version < ProtocolV50 {
return offset, CodeRefusedServerUnavailable
} else if !ValidTopic(string(buf)) {
rejectCode := CodeRefusedServerUnavailable
if msg.version == ProtocolV50 {
rejectCode = CodeInvalidTopicName
}
return offset, rejectCode
}
msg.topic = string(buf)
// The packet identifier field is only present in the PUBLISH packets where the
// QoS level is 1 or 2
if msg.QoS() != QoS0 {
offset += msg.decodePacketID(from[offset:])
}
if msg.version == ProtocolV50 {
msg.properties, n, err = decodeProperties(msg.Type(), from[offset:])
offset += n
if err != nil {
return offset, err
}
// if packet does not have topic set there must be topic alias set in properties
if len(msg.topic) == 0 {
reject := CodeProtocolError
if prop := msg.PropertyGet(PropertyTopicAlias); prop != nil {
if val, ok := prop.AsShort(); ok == nil && val > 0 {
reject = CodeSuccess
}
}
if reject != CodeSuccess {
return offset, reject
}
}
}
pLen := int(msg.remLen) - offset
// check payload len is not malformed
if pLen < 0 {
var rejectCode ReasonCode
if msg.version == ProtocolV50 {
rejectCode = CodeMalformedPacket
} else {
rejectCode = CodeRefusedServerUnavailable
}
return offset, rejectCode
}
// check payload is not malformed
if len(from[offset:]) < pLen {
var rejectCode ReasonCode
if msg.version == ProtocolV50 {
rejectCode = CodeMalformedPacket
} else {
rejectCode = CodeRefusedServerUnavailable
}
return offset, rejectCode
}
if pLen > 0 {
msg.payload = make([]byte, pLen)
copy(msg.payload, from[offset:offset+pLen])
offset += pLen
}
return offset, nil
}
func (msg *Publish) encodeMessage(to []byte) (int, error) {
if !ValidTopic(msg.topic) {
return 0, ErrInvalidTopic
}
if !msg.QoS().IsValid() {
return 0, ErrInvalidQoS
}
if msg.QoS() == QoS0 && msg.Dup() {
return 0, ErrDupViolation
}
// [MQTT-2.3.1]
if msg.QoS() != QoS0 && len(msg.packetID) == 0 {
return 0, ErrPackedIDZero
}
var err error
var n int
offset := 0
// [MQTT-3.3.2.1]
if n, err = WriteLPBytes(to[offset:], []byte(msg.topic)); err != nil {
return offset, err
}
offset += n
// [MQTT-3.3.2.2]
if msg.QoS() != QoS0 {
offset += msg.encodePacketID(to[offset:])
}
// V5.0 [MQTT-3.1.2.11]
if msg.version == ProtocolV50 {
if n, err = msg.properties.encode(to[offset:]); err != nil {
return offset + n, err
}
offset += n
}
offset += copy(to[offset:], msg.payload)
return offset, nil
}
func (msg *Publish) size() int {
total := 2 + len(msg.topic) + len(msg.payload)
if msg.QoS() != 0 {
// QoS1/2 packets must include packet id
total += 2
}
// v5.0 [MQTT-3.1.2.11]
if msg.version == ProtocolV50 {
total += int(msg.properties.FullLen())
}
return total
}