Class: Pgoutput::BinaryParser

Inherits:

Object

• Object
• Pgoutput::BinaryParser

Defined in:

lib/pgoutput/binary_parser.rb

Overview

Offset-based binary parser for one PostgreSQL pgoutput logical replication message payload.

A parser instance is intentionally short-lived and mutable while reading a single payload. Its returned message object is deeply frozen/shareable and may cross Ractor boundaries safely.

rubocop:disable Metrics/ClassLength

Instance Method Summary

• #initialize(payload) ⇒ void constructor

  Initializes parser state for the supplied payload.

• #parse ⇒ Pgoutput::Messages::Begin, ...

  Parse one supported pgoutput message.

Constructor Details

#initialize(payload) ⇒ void

Returns initializes parser state for the supplied payload.

Parameters:

• payload (String) —

  one pgoutput message payload from a CopyData frame.

# File 'lib/pgoutput/binary_parser.rb', line 16

def initialize(payload)
  @payload = payload.b
  @offset = 0
end

Instance Method Details

#parse ⇒ Pgoutput::Messages::Begin, ...

Parse one supported pgoutput message.

Supported MVP tags are ‘B`, `M`, `O`, `R`, `Y`, `I`, `U`, `D`, `T`, and `C`.

rubocop:disable Metrics/CyclomaticComplexity

Returns:

• (Pgoutput::Messages::Begin, Pgoutput::Messages::Message, Pgoutput::Messages::Origin, Pgoutput::Messages::Relation, Pgoutput::Messages::Type, Pgoutput::Messages::Truncate, Pgoutput::Messages::Insert, Pgoutput::Messages::Update, Pgoutput::Messages::Delete, Pgoutput::Messages::Commit) —

  parsed immutable message object for the payload tag.

Raises:

• (UnsupportedMessageError) —

  if the message tag is unsupported.

• (TruncatedMessageError) —

  if the payload is incomplete.

# File 'lib/pgoutput/binary_parser.rb', line 34

def parse
  case read_byte_chr
  when "B" then parse_begin
  when "M" then parse_message
  when "O" then parse_origin
  when "R" then parse_relation
  when "Y" then parse_type
  when "I" then parse_insert
  when "U" then parse_update
  when "D" then parse_delete
  when "T" then parse_truncate
  when "C" then parse_commit
  else
    raise UnsupportedMessageError, "unsupported pgoutput message tag"
  end
end