-
Notifications
You must be signed in to change notification settings - Fork 11
/
subscribe.go
181 lines (147 loc) · 4.16 KB
/
subscribe.go
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
// 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 mqttp
import (
"unicode/utf8"
)
// Subscribe The SUBSCRIBE Packet is sent from the Client to the Server to create one or more
// Subscriptions. Each Subscription registers a Client’s interest in one or more
// Topics. The Server sends PUBLISH Packets to the Client in order to forward
// Application Messages that were published to Topics that match these Subscriptions.
// The SUBSCRIBE Packet also specifies (for each Subscription) the maximum QoS with
// which the Server can send Application Messages to the Client.
type Subscribe struct {
header
topics []*Topic
}
var _ IFace = (*Subscribe)(nil)
func newSubscribe() *Subscribe {
return &Subscribe{}
}
// NewSubscribe creates a new SUBSCRIBE packet
func NewSubscribe(v ProtocolVersion) *Subscribe {
p := newSubscribe()
p.init(SUBSCRIBE, v, p.size, p.encodeMessage, p.decodeMessage)
return p
}
// ForEachTopic loop through list of topics
func (msg *Subscribe) ForEachTopic(fn func(*Topic) error) error {
for _, t := range msg.topics {
if err := fn(t); err != nil {
return err
}
}
return nil
}
// AddTopic adds a single topic to the message, along with the corresponding QoS.
// An error is returned if QoS is invalid.
func (msg *Subscribe) AddTopic(topic *Topic) error {
msg.topics = append(msg.topics, topic)
return nil
}
// SetPacketID sets the ID of the packet.
func (msg *Subscribe) SetPacketID(v IDType) {
msg.setPacketID(v)
}
// decode message
func (msg *Subscribe) decodeMessage(from []byte) (int, error) {
if len(from) < 2 {
return 0, CodeProtocolError
}
offset := msg.decodePacketID(from)
// v5 [MQTT-3.1.2.11] specifies properties in variable header
if msg.version == ProtocolV50 {
n, err := msg.properties.decode(msg.Type(), from[offset:])
offset += n
if err != nil {
return offset, err
}
}
remLen := int(msg.remLen) - offset
for remLen > 0 {
t, n, err := ReadLPBytes(from[offset:])
offset += n
if err != nil {
return offset, err
}
// [MQTT-3.8.3-1]
if !utf8.Valid(t) {
rejectReason := CodeProtocolError
if msg.version <= ProtocolV50 {
rejectReason = CodeRefusedServerUnavailable
}
return 0, rejectReason
}
if len(from[offset:]) < 1 {
return offset, CodeProtocolError
}
subsOptions := SubscriptionOptions(from[offset])
offset++
if msg.version == ProtocolV50 && (subsOptions.Raw()&maskSubscriptionReserved) != 0 {
return offset, CodeProtocolError
}
var topic *Topic
if topic, err = NewSubscribeTopic(t, subsOptions); err != nil {
return offset, CodeProtocolError
}
msg.topics = append(msg.topics, topic)
remLen = remLen - n - 1
}
// [MQTT-3.8.3-3]
if len(msg.topics) == 0 {
rejectReason := CodeProtocolError
if msg.version <= ProtocolV50 {
rejectReason = CodeRefusedServerUnavailable
}
return 0, rejectReason
}
return offset, nil
}
func (msg *Subscribe) encodeMessage(to []byte) (int, error) {
// [MQTT-2.3.1]
if len(msg.packetID) == 0 {
return 0, ErrPackedIDZero
}
offset := msg.encodePacketID(to)
// V5.0 [MQTT-3.1.2.11]
if msg.version == ProtocolV50 {
n, err := msg.properties.encode(to[offset:])
offset += n
if err != nil {
return offset, err
}
}
for _, t := range msg.topics {
n, err := WriteLPBytes(to[offset:], t.full)
offset += n
if err != nil {
return offset, err
}
to[offset] = t.ops.Raw()
offset++
}
return offset, nil
}
func (msg *Subscribe) size() int {
// packet ID
total := 2
// v5.0 [MQTT-3.1.2.11]
if msg.version == ProtocolV50 {
total += msg.properties.FullLen()
}
for _, t := range msg.topics {
total += 2 + len(t.full) + 1
}
return total
}