py-libp2p/libp2p/io/msgio.py
2019-08-24 22:47:56 +02:00

25 lines
896 B
Python

from libp2p.network.connection.raw_connection_interface import IRawConnection
from .exceptions import MissingLengthException, MissingMessageException
SIZE_LEN_BYTES = 4
# TODO unify w/ https://github.com/libp2p/py-libp2p/blob/1aed52856f56a4b791696bbcbac31b5f9c2e88c9/libp2p/utils.py#L85-L99 # noqa: E501
def encode(msg_bytes: bytes) -> bytes:
len_prefix = len(msg_bytes).to_bytes(SIZE_LEN_BYTES, "big")
return len_prefix + msg_bytes
async def read_next_message(reader: IRawConnection) -> bytes:
len_bytes = await reader.read(SIZE_LEN_BYTES)
if len(len_bytes) != SIZE_LEN_BYTES:
raise MissingLengthException()
len_int = int.from_bytes(len_bytes, "big")
next_msg = await reader.read(len_int)
if len(next_msg) != len_int:
# TODO makes sense to keep reading until this condition is true?
raise MissingMessageException()
return next_msg