Purpose

The symbol extension (type 0) provides efficient serialization of Ruby symbols.

References

Concepts

Registering symbol type 

factory.register_type(0, Symbol)

Where,

  • 0 is the type ID for symbols

  • The extension uses to_sym and to_s for packing/unpacking

Symbol serialization 

factory.register_type(0, Symbol)
binary = factory.pack(:hello_symbol)
result = factory.unpack(binary) # => :hello_symbol

Where,

  • Symbols are serialized as their string representation

  • Deserialization converts the string back to a symbol

  • This is more efficient than serializing as strings

Examples

Example 1. Symbol serialization in data structures
factory = Messagepack::Factory.new
factory.register_type(0, Symbol)

data = {
  status: :active,
  priority: :high,
  tags: [:important, :urgent]
}

binary = factory.pack(data)
result = factory.unpack(binary)
# => {:status=>:active, :priority=>:high, :tags=>[:important, :urgent]}
The symbol extension is not registered by default. You must register it explicitly if you want to preserve symbols when serializing.