Class: PulsarSdk::Protocol::Structure

Inherits:
Object
  • Object
show all
Includes:
Tweaks::CleanInspect
Defined in:
lib/pulsar_sdk/protocol/structure.rb

Constant Summary collapse

MAGIC_NUMBER =
MAGIC_NUMBER
CHECKSUM
METADATA_SIZE
METADATA
PAYLOAD 
[0x0e, 0x01].pack('C*').freeze
MAGIC_NUMBER_LEN = 
MAGIC_NUMBER.size
CHECKSUM_LEN = 
4
METADATA_SIZE_LEN = 
4

Instance Method Summary collapse

Methods included from Tweaks::CleanInspect

#inspect

Constructor Details

#initialize(buff) ⇒ Structure

Returns a new instance of Structure.



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# File 'lib/pulsar_sdk/protocol/structure.rb', line 12

def initialize(buff)
  @buff = buff
  rewind
end

Instance Method Details

#decode ⇒ Object 



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# File 'lib/pulsar_sdk/protocol/structure.rb', line 17

def decode
  metadata = nil

  message = PulsarSdk::Protocol::Message.new

  mn_bytes = read_magic_number
  if mn_bytes == MAGIC_NUMBER
    _checksum = read_checksum
    # TODO 可能需要校验一下，防止错误消息
    metadata = read_metadata
  else
    rewind(MAGIC_NUMBER_LEN)
    metadata = read_metadata
  end

  msg = read_remaining

  # NOTE 同为Ruby SDK时可以根据Content-Type预先还原
  # 复杂类型依旧为string，需要特别注意
  metadata.properties.each do |x|
    next unless x.key.to_s =~ /Content-Type/i
    next unless x.value.to_s =~ /json/i
    PulsarSdk.logger.info("#{self.class}::#{__method__}"){"Found json encode remark, parse JSON mesaage!"}
    msg = JSON.parse(msg)
  end

  message.assign_attributes(
    publish_time: metadata.publish_time,
    event_time: metadata.event_time,
    partition_key: metadata.partition_key,
    properties: metadata.properties,
    payload: msg
  )

  message
end

#read_checksum ⇒ Object

crc32



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# File 'lib/pulsar_sdk/protocol/structure.rb', line 66

def read_checksum
  read(CHECKSUM_LEN)
end

#read_magic_number ⇒ Object 



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# File 'lib/pulsar_sdk/protocol/structure.rb', line 61

def read_magic_number
  read(MAGIC_NUMBER_LEN)
end

#read_metadata ⇒ Object 



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# File 'lib/pulsar_sdk/protocol/structure.rb', line 70

def read_metadata
  metadata_size = read(METADATA_SIZE_LEN, 'N')
  metadata_bytes = read(metadata_size)
  Pulsar::Proto::MessageMetadata.decode(metadata_bytes)
end

#read_remaining ⇒ Object 



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# File 'lib/pulsar_sdk/protocol/structure.rb', line 76

def read_remaining
  payload_size = @buff.size - @readed
  return if payload_size <= 0
  read(payload_size)
end

#rewind(x = nil) ⇒ Object

回退若干字节，方便处理非连续段



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# File 'lib/pulsar_sdk/protocol/structure.rb', line 55

def rewind(x = nil)
  return @readed = 0 if x.nil?

  @readed -= x
end