Class: SDN::Message

Inherits:
Object
  • Object
show all
Includes:
Helpers
Defined in:
lib/sdn/message.rb,
lib/sdn/messages/get.rb,
lib/sdn/messages/set.rb,
lib/sdn/messages/post.rb,
lib/sdn/messages/control.rb,
lib/sdn/messages/helpers.rb

Defined Under Namespace

Modules: Helpers Classes: Ack, GetGroupAddr, GetMotorDirection, GetMotorIP, GetMotorLimits, GetMotorPosition, GetMotorRollingSpeed, GetMotorStatus, GetNodeAddr, GetNodeLabel, GetNodeSerialNumber, GetNodeStackVersion, Move, MoveOf, MoveTo, Nack, PostGroupAddr, PostMotorDirection, PostMotorIP, PostMotorLimits, PostMotorPosition, PostMotorRollingSpeed, PostMotorStatus, PostNodeAddr, PostNodeLabel, PostNodeSerialNumber, PostNodeStackVersion, SetFactoryDefault, SetGroupAddr, SetMotorDirection, SetMotorIP, SetMotorLimits, SetMotorRollingSpeed, SetNodeLabel, SimpleRequest, Stop, UnknownMessage, Wink

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Methods included from Helpers

#checksum, #from_number, #from_string, #is_group_address?, #parse_address, #print_address, #to_number, #to_string, #transform_param

Constructor Details

#initialize(reserved: nil, ack_requested: false, src: nil, dest: nil) ⇒ Message

Returns a new instance of Message.



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# File 'lib/sdn/message.rb', line 89

def initialize(reserved: nil, ack_requested: false, src: nil, dest: nil)
  @reserved = reserved || 0x02 # message sent to Sonesse 30
  @ack_requested = ack_requested
  if src.nil? && is_group_address?(dest)
    src = dest
    dest = nil
  end
  @src = src || [0, 0, 1]
  @dest = dest || [0, 0, 0]
end

Instance Attribute Details

#ack_requested ⇒ Object (readonly)

Returns the value of attribute ack_requested.



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# File 'lib/sdn/message.rb', line 87

def ack_requested
  @ack_requested
end

#dest ⇒ Object (readonly)

Returns the value of attribute dest.



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# File 'lib/sdn/message.rb', line 87

def dest
  @dest
end

#reserved ⇒ Object (readonly)

Returns the value of attribute reserved.



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# File 'lib/sdn/message.rb', line 87

def reserved
  @reserved
end

#src ⇒ Object (readonly)

Returns the value of attribute src.



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# File 'lib/sdn/message.rb', line 87

def src
  @src
end

Class Method Details

.parse(io) ⇒ Object 



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# File 'lib/sdn/message.rb', line 23

def parse(io)
  io = StringIO.new(io) if io.is_a?(String)
  data = readpartial(io, 2, allow_empty: false)
  if data.length != 2
    # don't have enough data yet; buffer it
    io.ungetbyte(data.first) if data.length == 1
    raise MalformedMessage, "Could not get message type and length"
  end
  msg = to_number(data.first)
  length = to_number(data.last)
  ack_requested = length & 0x80 == 0x80
  length &= 0x7f
  if length < 11 || length > 32
    # only skip over one byte to try and re-sync
    io.ungetbyte(data.last)
    raise MalformedMessage, "Message has bogus length: #{length}"
  end
  data.concat(readpartial(io, length - 4))
  unless data.length == length - 2
    data.reverse.each { |byte| io.ungetbyte(byte) }
    raise MalformedMessage, "Missing data: got #{data.length} expected #{length}"
  end

  message_class = constants.find { |c| (const_get(c, false).const_get(:MSG, false) rescue nil) == msg }
  message_class = const_get(message_class, false) if message_class
  message_class ||= UnknownMessage

  bogus_checksums = [SetNodeLabel::MSG, PostNodeLabel::MSG].include?(msg)

  calculated_sum = checksum(data)
  read_sum = readpartial(io, 2)
  if read_sum.length == 0 || (!bogus_checksums && read_sum.length == 1)
    read_sum.each { |byte| io.ungetbyte(byte) }
    data.reverse.each { |byte| io.ungetbyte(byte) }
    raise MalformedMessage, "Missing data: got #{data.length} expected #{length}"
  end

  # check both the proper checksum, and a truncated checksum
  unless calculated_sum == read_sum || (bogus_checksums && calculated_sum.last == read_sum.first)
      raw_message = (data + read_sum).map { |b| '%02x' % b }.join(' ')
      # skip over single byte to try and re-sync
      data.shift
      read_sum.reverse.each { |byte| io.ungetbyte(byte) }
      data.reverse.each { |byte| io.ungetbyte(byte) }
      raise MalformedMessage, "Checksum mismatch for #{message_class.name}: #{raw_message}"
  end
  # the checksum was truncated; put back the unused byte
  io.ungetbyte(read_sum.last) if calculated_sum != read_sum && read_sum.length == 2

  puts "read #{(data + read_sum).map { |b| '%02x' % b }.join(' ')}"

  reserved = to_number(data[2])
  src = transform_param(data[3..5])
  dest = transform_param(data[6..8])
  result = message_class.new(reserved: reserved, ack_requested: ack_requested, src: src, dest: dest)
  result.parse(data[9..-1])
  result.msg = msg if message_class == UnknownMessage
  result
end

.readpartial(io, length, allow_empty: true) ⇒ Object 



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# File 'lib/sdn/message.rb', line 8

def readpartial(io, length, allow_empty: true)
  data = []
  while data.length < length
    begin
      data.concat(io.read_nonblock(length - data.length).bytes)
    rescue EOFError
      break
    rescue IO::WaitReadable
      break if allow_empty
      IO.select([io])
    end
  end
  data
end

Instance Method Details

#class_inspect ⇒ Object 



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# File 'lib/sdn/message.rb', line 118

def class_inspect
  ivars = instance_variables - [:@reserved, :@ack_requested, :@src, :@dest]
  return if ivars.empty?
  ivars.map { |iv| ", #{iv}=#{instance_variable_get(iv).inspect}" }.join
end

#inspect ⇒ Object 



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# File 'lib/sdn/message.rb', line 114

def inspect
  "#<%s @reserved=%02xh, @ack_requested=%s, @src=%s, @dest=%s%s>" % [self.class.name, reserved, ack_requested, print_address(src), print_address(dest), class_inspect]
end

#parse(params) ⇒ Object

Raises:



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# File 'lib/sdn/message.rb', line 100

def parse(params)
  raise MalformedMessage, "unrecognized params for #{self.class.name}: #{params.map { |b| '%02x' % b }}" if self.class.const_defined?(:PARAMS_LENGTH) && params.length != self.class.const_get(:PARAMS_LENGTH)
end

#serialize ⇒ Object 



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# File 'lib/sdn/message.rb', line 104

def serialize
  result = transform_param(reserved) + transform_param(src) + transform_param(dest) + params
  length = result.length + 4
  length |= 0x80 if ack_requested
  result = transform_param(self.class.const_get(:MSG)) + transform_param(length) + result
  result.concat(checksum(result))
  puts "wrote #{result.map { |b| '%02x' % b }.join(' ')}"
  result.pack("C*")
end