Class: MQTT::SN::Packet

Inherits:
Object
  • Object
show all
Defined in:
lib/mqtt/sn/packet.rb

Overview

Class representing a MQTT::SN Packet Performs binary encoding and decoding of headers

Defined Under Namespace

Classes: Advertise, Connack, Connect, Disconnect, Gwinfo, Pingreq, Pingresp, Puback, Pubcomp, Publish, Pubrec, Pubrel, Regack, Register, Searchgw, Suback, Subscribe, Unsuback, Unsubscribe, Willmsg, Willmsgreq, Willmsgresp, Willmsgupd, Willtopic, Willtopicreq, Willtopicresp, Willtopicupd

Constant Summary collapse

DEFAULTS = 
{}.freeze

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(args = {}) ⇒ Packet

Create a new empty packet



38
39
40
 
# File 'lib/mqtt/sn/packet.rb', line 38

def initialize(args = {})
  update_attributes(self.class::DEFAULTS.merge(args))
end

Instance Attribute Details

#clean_session ⇒ Object

When true, subscriptions are deleted after disconnect



13
14
15
 
# File 'lib/mqtt/sn/packet.rb', line 13

def clean_session
  @clean_session
end

#duplicate ⇒ Object

Duplicate delivery flag



9
10
11
 
# File 'lib/mqtt/sn/packet.rb', line 9

def duplicate
  @duplicate
end

#qos ⇒ Object

Quality of Service level



10
11
12
 
# File 'lib/mqtt/sn/packet.rb', line 10

def qos
  @qos
end

#request_will ⇒ Object

Request that gateway prompts for Will



12
13
14
 
# File 'lib/mqtt/sn/packet.rb', line 12

def request_will
  @request_will
end

#retain ⇒ Object

Retain flag



11
12
13
 
# File 'lib/mqtt/sn/packet.rb', line 11

def retain
  @retain
end

#topic_id_type ⇒ Object

One of :normal, :predefined or :short



14
15
16
 
# File 'lib/mqtt/sn/packet.rb', line 14

def topic_id_type
  @topic_id_type
end

Class Method Details

.parse(buffer) ⇒ Object

Parse buffer into new packet object

Raises:



19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
 
# File 'lib/mqtt/sn/packet.rb', line 19

def self.parse(buffer)
  # Parse the fixed header (length and type)
  length, type_id, body = buffer.unpack('CCa*')
  length, type_id, body = buffer.unpack('xnCa*') if length == 1

  # Double-check the length
  raise ProtocolException, 'Length of packet is not the same as the length header' if buffer.length != length

  packet_class = PACKET_TYPES[type_id]
  raise ProtocolException, "Invalid packet type identifier: #{type_id}" if packet_class.nil?

  # Create a new packet object
  packet = packet_class.new
  packet.parse_body(body)

  packet
end

Instance Method Details

#parse_body(buffer) ⇒ Object 



72
 
# File 'lib/mqtt/sn/packet.rb', line 72

def parse_body(buffer); end

#to_s ⇒ Object

Serialise the packet



57
58
59
60
61
62
63
64
65
66
67
68
69
70
 
# File 'lib/mqtt/sn/packet.rb', line 57

def to_s
  # Get the packet's variable header and payload
  body = encode_body

  # Build up the body length field bytes
  body_length = body.length
  raise 'MQTT-SN Packet is too big, maximum packet body size is 65531' if body_length > 65_531

  if body_length > 253
    [0x01, body_length + 4, type_id].pack('CnC') + body
  else
    [body_length + 2, type_id].pack('CC') + body
  end
end

#type_id ⇒ Object

Get the identifer for this packet type



49
50
51
52
53
54
 
# File 'lib/mqtt/sn/packet.rb', line 49

def type_id
  PACKET_TYPES.each_pair do |key, value|
    return key if instance_of?(value)
  end
  raise "Invalid packet type: #{self.class}"
end

#update_attributes(attr = {}) ⇒ Object 



42
43
44
45
46
 
# File 'lib/mqtt/sn/packet.rb', line 42

def update_attributes(attr = {})
  attr.each_pair do |k, v|
    send("#{k}=", v)
  end
end