Class: MQTT::Packet::Publish

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

Overview

Class representing an MQTT Publish message

Constant Summary collapse

ATTR_DEFAULTS =

Default attribute values

{
  :topic => nil,
  :payload => ''
}

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 = {}) ⇒ Publish

Create a new Publish packet



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# File 'lib/mqtt/packet.rb', line 318

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

Instance Attribute Details

#duplicate ⇒ Object

Duplicate delivery flag



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# File 'lib/mqtt/packet.rb', line 297

def duplicate
  @duplicate
end

#payload ⇒ Object

The data to be published



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# File 'lib/mqtt/packet.rb', line 309

def payload
  @payload
end

#qos ⇒ Object

Quality of Service level (0, 1, 2)



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# File 'lib/mqtt/packet.rb', line 303

def qos
  @qos
end

#retain ⇒ Object

Retain flag



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# File 'lib/mqtt/packet.rb', line 300

def retain
  @retain
end

#topic ⇒ Object

The topic name to publish to



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# File 'lib/mqtt/packet.rb', line 306

def topic
  @topic
end

Instance Method Details

#encode_body ⇒ Object

Get serialisation of packet’s body



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# File 'lib/mqtt/packet.rb', line 364

def encode_body
  body = ''
  if @topic.nil? or @topic.to_s.empty?
    raise "Invalid topic name when serialising packet"
  end
  body += encode_string(@topic)
  body += encode_short(@id) unless qos == 0
  body += payload.to_s.dup.force_encoding('ASCII-8BIT')
  return body
end

#inspect ⇒ Object

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



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# File 'lib/mqtt/packet.rb', line 395

def inspect
  "\#<#{self.class}: " +
  "d#{duplicate ? '1' : '0'}, " +
  "q#{qos}, " +
  "r#{retain ? '1' : '0'}, " +
  "m#{id}, " +
  "'#{topic}', " +
  "#{inspect_payload}>"
end

#parse_body(buffer) ⇒ Object

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



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# File 'lib/mqtt/packet.rb', line 376

def parse_body(buffer)
  super(buffer)
  @topic = shift_string(buffer)
  @id = shift_short(buffer) unless qos == 0
  @payload = buffer
end

#validate_flags ⇒ Object

Check that fixed header flags are valid for this packet type



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# File 'lib/mqtt/packet.rb', line 385

def validate_flags
  if qos == 3
    raise ProtocolException.new("Invalid packet: QoS value of 3 is not allowed")
  end
  if qos == 0 and duplicate
    raise ProtocolException.new("Invalid packet: DUP cannot be set for QoS 0")
  end
end