Class: Kafka::Message

Inherits:
Object
  • Object
show all
Defined in:
lib/kafka/message.rb

Overview

A message. The format of an N byte message is the following: 1 byte “magic” identifier to allow format changes 4 byte CRC32 of the payload N - 5 byte payload

Constant Summary collapse

MAGIC_IDENTIFIER_DEFAULT = 
0

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(payload = nil, magic = MAGIC_IDENTIFIER_DEFAULT, checksum = nil) ⇒ Message

Returns a new instance of Message.



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# File 'lib/kafka/message.rb', line 27

def initialize(payload = nil, magic = MAGIC_IDENTIFIER_DEFAULT, checksum = nil)
  self.magic    = magic
  self.payload  = payload
  self.checksum = checksum || self.calculate_checksum
end

Instance Attribute Details

#checksum ⇒ Object

Returns the value of attribute checksum.



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# File 'lib/kafka/message.rb', line 25

def checksum
  @checksum
end

#magic ⇒ Object

Returns the value of attribute magic.



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# File 'lib/kafka/message.rb', line 25

def magic
  @magic
end

#payload ⇒ Object

Returns the value of attribute payload.



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# File 'lib/kafka/message.rb', line 25

def payload
  @payload
end

Class Method Details

.parse_from(binary) ⇒ Object 



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# File 'lib/kafka/message.rb', line 41

def self.parse_from(binary)
  size     = binary[0, 4].unpack("N").shift.to_i
  magic    = binary[4, 1].unpack("C").shift
  checksum = binary[5, 4].unpack("N").shift
  payload  = binary[9, size] # 5 = 1 + 4 is Magic + Checksum
  return Kafka::Message.new(payload, magic, checksum)
end

Instance Method Details

#calculate_checksum ⇒ Object 



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# File 'lib/kafka/message.rb', line 33

def calculate_checksum
  Zlib.crc32(self.payload)
end

#valid? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/kafka/message.rb', line 37

def valid?
  self.checksum == Zlib.crc32(self.payload)
end