rubymarshal

RubyMarshal

Read and write Ruby-marshalled data. Only basics Ruby data types can be directly read and written, but you can use any custom Python and Ruby types:

• float,
• bool,
• int,
• str (mapped to rubymarshal.classes.RubyString if dumped with instance variables),
• nil (mapped to None in Python),
• array (mapped to list),
• hash (mapped to dict),
• symbols and other classes are mapped to specific Python classes.

Installation

    pip install rubymarshal

Usage

    from rubymarshal.reader import loads, load
    from rubymarshal.writer import writes, write
    with open('my_file', 'rb') as fd:
        content = load(fd)
    with open('my_file', 'wb') as fd:
        write(fd, content)
    loads(b"\x04\bi\xfe\x00\xff")
    writes(-256)

You can map custom Ruby types to Python ones:

    from rubymarshal.reader import loads
    from rubymarshal.classes import RubyObject, registry

    class DomainError(RubyObject):
        ruby_class_name = "Math::DomainError"
    
    registry.register(DomainError)

    loads(b'\x04\x08c\x16Math::DomainError')

You can use custom registries instead of the global one:

    from rubymarshal.reader import loads
    from rubymarshal.classes import RubyObject, ClassRegistry

    class DomainError(RubyObject):
        ruby_class_name = "Math::DomainError"
    
    registry = ClassRegistry()
    registry.register(DomainError)

    loads(b'\x04\x08c\x16Math::DomainError', registry=registry)

You can use Ruby's symbols:

    from rubymarshal.reader import loads
    from rubymarshal.writer import writes
    from rubymarshal.classes import Symbol
    
    x = Symbol("test")
    dump = writes(Symbol("test"))
    y = loads(dump)
    assert y is x

The default Writer class is customizable to write custom Python classes:

    from rubymarshal.writer import writes, Writer
    from rubymarshal.classes import Symbol
    
    class Constant:
        def __init__(self, name):
            self.name = name
    
    class ConstantWriter(Writer):
        def write_python_object(self, obj):
            if isinstance(obj, Constant):
                return self.write(Symbol(obj.name))
            super().write_python_object(obj)
    
    dump = writes([Constant("test")], cls=ConstantWriter)
    print(dump)

Infos

• Code is on github: https://github.com/d9pouces/RubyMarshal
• Documentation is on readthedocs: http://rubymarshal.readthedocs.org/en/latest/
• Tests are on travis-ci: https://travis-ci.org/d9pouces/RubyMarshal