Class: EventMachine::MQTTSN::Packet

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

Overview

Class representing a MQTTSN Packet Performs binary encoding and decoding of headers

Defined Under Namespace

Classes: Connack, Connect, Disconnect, Pingreq, Pingresp, Publish, Regack, Register, Suback, Subscribe

Constant Summary collapse

DEFAULTS = 
{}

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(args = {}) ⇒ Packet

Create a new empty packet



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# File 'lib/em/mqtt-sn/packet.rb', line 41

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

Instance Attribute Details

#clean_session ⇒ Object

When true, subscriptions are deleted after disconnect



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# File 'lib/em/mqtt-sn/packet.rb', line 10

def clean_session
  @clean_session
end

#duplicate ⇒ Object

Duplicate delivery flag



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# File 'lib/em/mqtt-sn/packet.rb', line 6

def duplicate
  @duplicate
end

#qos ⇒ Object

Quality of Service level



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# File 'lib/em/mqtt-sn/packet.rb', line 7

def qos
  @qos
end

#request_will ⇒ Object

Request that gateway prompts for Will



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# File 'lib/em/mqtt-sn/packet.rb', line 9

def request_will
  @request_will
end

#retain ⇒ Object

Retain flag



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# File 'lib/em/mqtt-sn/packet.rb', line 8

def retain
  @retain
end

#topic_id_type ⇒ Object

One of :normal, :predefined or :short



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# File 'lib/em/mqtt-sn/packet.rb', line 11

def topic_id_type
  @topic_id_type
end

Class Method Details

.parse(buffer) ⇒ Object

Parse buffer into new packet object



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# File 'lib/em/mqtt-sn/packet.rb', line 16

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

  # Double-check the length
  if buffer.length != length
    raise ProtocolException.new("Length of packet is not the same as the length header")
  end

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

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

  return packet
end

Instance Method Details

#parse_body(buffer) ⇒ Object 



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# File 'lib/em/mqtt-sn/packet.rb', line 75

def parse_body(buffer)
end

#to_s ⇒ Object

Serialise the packet



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# File 'lib/em/mqtt-sn/packet.rb', line 60

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

  # Build up the body length field bytes
  body_length = body.length
  if body_length > 65531
    raise "Packet too big"
  elsif 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



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# File 'lib/em/mqtt-sn/packet.rb', line 52

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

#update_attributes(attr = {}) ⇒ Object 



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# File 'lib/em/mqtt-sn/packet.rb', line 45

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