The lodum.msgpack module provides MessagePack serialization and deserialization for lodum-enabled classes with support for streaming.
Installation
Requires msgpack. Install with:
pip install lodum[msgpack]
Functions
dump
def dump(
obj: Any,
target: Optional[Union[IO[bytes], Path]] = None,
**kwargs
) -> Optional[bytes]
target
Optional[Union[IO[bytes], Path]]
Optional file-like object or Path to write to.
Additional arguments for msgpack.packb. Note: use_bin_type=True is set by default.
target is None, otherwise None.
Raises: ImportError if msgpack is not installed.
Example:
import lodum
from lodum import msgpack
@lodum
class Person:
name: str
age: int
person = Person(name="Alice", age=30)
# Serialize to bytes
msgpack_bytes = msgpack.dump(person)
# Serialize to file
msgpack.dump(person, Path("person.msgpack"))
dumps
def dumps(obj: Any, **kwargs) -> bytes
dump(obj).
Additional arguments for msgpack.packb.
load
def load(
cls: Type[T],
source: Union[bytes, IO[bytes], Path],
max_size: int = DEFAULT_MAX_SIZE
) -> T
The class to instantiate.
source
Union[bytes, IO[bytes], Path]
required
MessagePack bytes, file-like object, or Path.
max_size
int
default:"DEFAULT_MAX_SIZE"
Maximum allowed size for bytes input.
cls.
Raises:
ImportError if msgpack is not installed.DeserializationError if the input is invalid or exceeds max_size.
Example:
import lodum
from lodum import msgpack
@lodum
class Person:
name: str
age: int
# Load from bytes
msgpack_bytes = b'\x82\xa4name\xa5Alice\xa3age\x1e'
person = msgpack.load(Person, msgpack_bytes)
# Load from file
person = msgpack.load(Person, Path("person.msgpack"))
loads
def loads(cls: Type[T], packed_bytes: bytes, **kwargs) -> T
load(cls, source).
The class to instantiate.
MessagePack bytes to parse.
Additional arguments (e.g., max_size).
cls.
stream
def stream(cls: Type[T], source: Union[IO[bytes], Path]) -> Iterator[T]
The class to instantiate for each item.
source
Union[IO[bytes], Path]
required
A binary stream, file-like object, or Path.
cls.
Raises: ImportError if msgpack is not installed.
Example:
import lodum
from lodum import msgpack
@lodum
class Person:
name: str
age: int
# Stream from file containing concatenated MessagePack objects
for person in msgpack.stream(Person, Path("people.msgpack")):
print(person.name, person.age)
Notes
- MessagePack is a binary format that is more compact than JSON
- The
use_bin_type=True option is set by default to distinguish between strings and binary data
- Native bytes support without base64 encoding