forked from platypush/platypush
78 lines
2.1 KiB
Python
78 lines
2.1 KiB
Python
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import logging
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import json
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import os
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import time
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from .. import Backend
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from platypush.message import Message
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from platypush.message.request import Request
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from platypush.message.response import Response
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class LocalBackend(Backend):
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""" Sends and receive messages on two distinct local FIFOs, one for
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the requests and one for the responses """
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def __init__(self, request_fifo, response_fifo, **kwargs):
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super().__init__(**kwargs)
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self.request_fifo = request_fifo
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self.response_fifo = response_fifo
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try: os.mkfifo(self.request_fifo)
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except FileExistsError as e: pass
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try: os.mkfifo(self.response_fifo)
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except FileExistsError as e: pass
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def send_message(self, msg):
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fifo = self.response_fifo \
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if isinstance(msg, Response) or self._request_context \
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else self.request_fifo
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msg = '{}\n'.format(str(msg)).encode('utf-8')
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with open(fifo, 'wb') as f:
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f.write(msg)
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def _get_next_message(self):
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fifo = self.response_fifo if self._request_context else self.request_fifo
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with open(fifo, 'rb', 0) as f:
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msg = f.readline()
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return Message.build(msg) if len(msg) else None
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def on_stop(self):
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try: os.remove(self.request_fifo)
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except: pass
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try: os.remove(self.response_fifo)
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except: pass
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def run(self):
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super().run()
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logging.info('Initialized local backend on {} and {}'.
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format(self.request_fifo, self.response_fifo))
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while not self.should_stop():
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try:
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msg = self._get_next_message()
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if not msg: continue
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except Exception as e:
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logging.exception(e)
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time.sleep(0.2)
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continue
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# logging.debug('Received message on the local backend: {}'.format(msg))
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logging.info('Received message on the local backend: {}'.format(msg))
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if self.should_stop(): break
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self.on_message(msg)
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# vim:sw=4:ts=4:et:
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