usocket UDP and sockaddr questions

[pfalcon]

bytes is immutable object, so it's only suitable for read-only arguments, which won't be changed. bytearray is mutable, and is suitable for buffers which will be written to.

[SpotlightKid]

So, I eventually figured out inet_ntop:

Code: Select all

import socket
import struct

INET_ADDRSTRLEN = 16

inet_ntop = getattr(socket, 'inet_ntop', None)
if not inet_ntop:
    import ffilib
    _inet_ntop = ffilib.libc().func("s", "inet_ntop", "iPpi")

    def inet_ntop(a):
        buf = bytearray(INET_ADDRSTRLEN)
        res = _inet_ntop(socket.AF_INET, a, buf, INET_ADDRSTRLEN)
        return res

def get_hostport(sockaddr):
    return inet_ntop(sockaddr[4:8]), struct.unpack('>H', sockaddr[2:4])[0]

[SpotlightKid]

bytes is immutable object, so it's only suitable for read-only arguments, which won't be changed. bytearray is mutable, and is suitable for buffers which will be written to.

This seems to tell otherwise:

https://github.com/micropython/micropyt ... /re.py#L68

[pfalcon]

This seems to tell otherwise:

Well, that's a hack, don't do it like that .

[pfalcon]

So, I eventually figured out inet_ntop:

And as it shows, inet_ntop() alone doesn't help. Stuff like sockaddr[4:8] is inherently not portable.

[pfalcon]

I for a long time wanted to post my simple example for working with UPNP (UDP, multicast), now I finally pushed them: https://github.com/pfalcon/micropython- ... aster/upnp . They also demonstrate usage of usocket.sockaddr() function which was added as outcome of discussion in this thread.

[pythoncoder]

A Python bytes object is immutable, a bytearray is mutable. Clear enough to this Python coder