How does ruby serialization (Marshaling) work?

The Ruby marshalling methods store the type of the object they're encoding. The way those two hooks work is like this:

• marshal_dump has to return some data describing the state of your object. Ruby couldn't care less about the format of this data — it just has to be something that your marshal_load method can use to reconstruct the object's state.

• marshal_load is called on the marshalled object just after it's been recreated. It's basically the initialize method for a marshalled object. It's passed whatever object marshal_dump returned and has to use that data to reconstruct its state.

Here's an example:

class Messenger  attr_accessor :name, :message  def marshal_dump    {'name' => name, 'message' => message}  end  def marshal_load(data)    self.name = data['name']    self.message = data['message']  endend

You can serialize raw numerical data using NArray as follows:

require 'narray'class NArray  def _dump level    Marshal.dump [to_s, typecode] + shape  end  def self._load arg    NArray.to_na *Marshal.load(arg)  endenddescribe NArray do  let(:arr) { NArray[[2, 3, 5], [7, 11, 13]] }  it 'should load and save an array' do    dumped = Marshal.dump arr    expect(Marshal.load(dumped)).to eq arr  endend