Class: MQTT::Packet::Subscribe

Inherits:
MQTT::Packet show all
Defined in:
lib/mqtt/packet.rb

Overview

Class representing an MQTT Client Subscribe packet

Constant Summary collapse

ATTR_DEFAULTS =

Default attribute values

{
  :topics => [],
  :flags => [false, true, false, false],
}

Instance Attribute Summary collapse

Attributes inherited from MQTT::Packet

#body_length, #flags, #id, #version

Instance Method Summary collapse

Methods inherited from MQTT::Packet

create_from_header, #message_id, #message_id=, parse, parse_header, read, #to_s, #type_id, #type_name, #update_attributes

Constructor Details

#initialize(args = {}) ⇒ Subscribe

Create a new Subscribe packet


777
778
779
# File 'lib/mqtt/packet.rb', line 777

def initialize(args={})
  super(ATTR_DEFAULTS.merge(args))
end

Instance Attribute Details

#topicsObject

One or more topic filters to subscribe to


768
769
770
# File 'lib/mqtt/packet.rb', line 768

def topics
  @topics
end

Instance Method Details

#encode_bodyObject

Get serialisation of packet's body


824
825
826
827
828
829
830
831
832
833
834
# File 'lib/mqtt/packet.rb', line 824

def encode_body
  if @topics.empty?
    raise "no topics given when serialising packet"
  end
  body = encode_short(@id)
  topics.each do |item|
    body += encode_string(item[0])
    body += encode_bytes(item[1])
  end
  return body
end

#inspectObject

Returns a human readable string, summarising the properties of the packet


857
858
859
860
861
862
# File 'lib/mqtt/packet.rb', line 857

def inspect
  _str = "\#<#{self.class}: 0x%2.2X, %s>" % [
    id,
    topics.map {|t| "'#{t[0]}':#{t[1]}"}.join(', ')
  ]
end

#parse_body(buffer) ⇒ Object

Parse the body (variable header and payload) of a packet


837
838
839
840
841
842
843
844
845
846
# File 'lib/mqtt/packet.rb', line 837

def parse_body(buffer)
  super(buffer)
  @id = shift_short(buffer)
  @topics = []
  while(buffer.bytesize>0)
    topic_name = shift_string(buffer)
    topic_qos = shift_byte(buffer)
    @topics << [topic_name,topic_qos]
  end
end

#validate_flagsObject

Check that fixed header flags are valid for this packet type


850
851
852
853
854
# File 'lib/mqtt/packet.rb', line 850

def validate_flags
  if @flags != [false, true, false, false]
    raise ProtocolException.new("Invalid flags in SUBSCRIBE packet header")
  end
end