Supporting alternative msgpack implementations

ormsgpack is a faster alternative to python-msgpack and since speed is critical/required in Web/ASGI application I think it would be nice to have support for using ormsgpack!

My current idea is to provide ormsgpack as an extra/optional dependency to msgpack-asgi (installed like pip install msgpack-asgi[ormsgpack]?) and provide two more classes to the public API ORMessagePackMiddleware and ORMessagePackResponse if ormsgpack can be imported.

I will happily create a PR and start working on this feature if this is something can be added to the project! 😄

[FaresAhmedb]

Very interesting! I like the latter implementation. Supporting ormsgpack directly into the library wouldn’t be needed then. There’s also a lot of MessagePack flavors out there like u-msgpack-python (A Pure Python implementation) so that would be definitely a win win for everyone.

But I assume this would be a breaking change, Right?

[florimondmanca]

@FaresAhmedb Thanks, that’s useful info.

Actually, I assume most users would be in a “I’m fine-tuning performance” mindset, which means writing some custom code would be acceptable — if not appropriate. So I wonder about another option: a public “backend” interface.

Like this:

class Packer(Protocol):
    def packb(self, obj: Any) -> bytes: ...
    def unpackb(self, data: bytes) -> Any: ...

We’d add a MsgPacker for our current behavior, and advanced users could do all sorts of customized things, e.g. what you suggested, ormsgpack for serialization vs msgpack for deserialization:

import ormsgpack
import msgpack

class OptimizedPacker:
    def packb(self, obj: Any) -> bytes:
        option = ormsgpack.OPT_NAIVE_UTC | ormsgpack.OPT_SERIALIZE_NUMPY
        return ormsgpack.packb(obj, option=option)

    def unpackb(self, data: bytes) -> Any:
        return msgpack.unpackb(data)

Usage:

from msgpack_asgi import MessagePackMiddleware

app = MessagePackMiddleware(..., packer=OptimizedPacker())

Or maybe, without classes, using packb=... and unpackb=... options (I think I prefer this style):

import ormsgpack
from typing import Any
from msgpack_asgi import MessagePackMiddleware

def packb(obj: Any) -> bytes:
    option = ormsgpack.OPT_NAIVE_UTC | ormsgpack.OPT_SERIALIZE_NUMPY
    return ormsgpack.packb(obj, option=option)

app = MessagePackMiddleware(..., packb=packb)  # Default `unpackb=partial(msgpack.unpackb, raw=False)`

Thoughts?