custom_yaml_serialization

🧩 Custom Object Serialization with Psych Tags

Psych lets you define custom YAML tags and hook into encode_with and init_with to control exactly how your objects are dumped and loaded. This is invaluable when you need to preserve object identity, custom metadata, or integrate with other systems expecting specific YAML structures.

require 'yaml'

class Person
  attr_accessor :name, :age

  # Called when dumping to YAML
  def encode_with(coder)
    coder.tag = '!person'
    coder['name'] = name
    coder['age']  = age
  end

  # Called when loading from YAML
  def init_with(coder)
    @name = coder['name']
    @age  = coder['age']
  end
end

person = Person.new
person.name = 'Alice'
person.age  = 30

# Dump with custom tag
yaml = person.to_yaml
puts yaml
# => --- !person
#    name: Alice
#    age: 30

# Load back into Person
loaded = YAML.load(yaml)
puts loaded.class  # => Person
puts loaded.name   # => "Alice"