platypush/platypush/message/__init__.py
2018-06-06 20:09:23 +02:00

68 lines
1.8 KiB
Python

import logging
import inspect
import json
logger = logging.getLogger(__name__)
class Message(object):
""" Message generic class """
def __str__(self):
"""
Overrides the str() operator and converts
the message into a UTF-8 JSON string
"""
return json.dumps({
attr: getattr(self, attr)
for attr in self.__dir__()
if not attr.startswith('_')
and not inspect.ismethod(getattr(self, attr))
}).replace('\n', ' ')
def __bytes__(self):
"""
Overrides the bytes() operator, converts the message into
its JSON-serialized UTF-8-encoded representation
"""
return str(self).encode('utf-8')
@classmethod
def parse(cls, msg):
"""
Parse a generic message into a key-value dictionary
Params:
msg -- Original message - can be a dictionary, a Message,
or a string/bytearray, as long as it's valid UTF-8 JSON
"""
if isinstance(msg, cls):
msg = str(msg)
if isinstance(msg, bytes) or isinstance(msg, bytearray):
msg = msg.decode('utf-8')
if isinstance(msg, str):
try:
msg = json.loads(msg.strip())
except:
logger.warning('Invalid JSON message: {}'.format(msg))
assert isinstance(msg, dict)
return msg
@classmethod
def build(cls, msg):
"""
Builds a Message object from a dictionary.
Params:
msg -- The message as a key-value dictionary, Message object or JSON string
"""
from platypush.utils import get_message_class_by_type
msg = cls.parse(msg)
msgtype = get_message_class_by_type(msg['type'])
if msgtype != cls: return msgtype.build(msg)
# vim:sw=4:ts=4:et: