70 lines
1.9 KiB
Python
70 lines
1.9 KiB
Python
from logging import getLogger
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from socket import socket
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from typing import Optional
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from platypush.commands import Command
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# pylint: disable=too-few-public-methods
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class CommandReader:
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"""
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Reads command objects from file-like I/O objects.
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"""
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_max_bufsize = 8192
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"""Maximum size of a command that can be queued in the stream."""
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_bufsize = 1024
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"""Size of the buffer used to read commands from the socket."""
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def __init__(self):
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self.logger = getLogger(__name__)
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self._buf = bytes()
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def _parse_command(self, data: bytes) -> Optional[Command]:
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"""
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Parses a command from the received data.
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:param data: Data received from the socket
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:return: The parsed command
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"""
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try:
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return Command.parse(data)
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except ValueError as e:
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self.logger.warning('Error while parsing command: %s', e)
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return None
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def read(self, sock: socket) -> Optional[Command]:
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"""
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Parses the next command from the file-like I/O object.
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:param fp: The file-like I/O object to read from.
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:return: The parsed command.
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"""
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try:
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data = sock.recv(self._bufsize)
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except OSError as e:
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self.logger.warning(
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'Error while reading from socket %s: %s', sock.getsockname(), e
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)
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return None
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for ch in data:
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if bytes([ch]) == Command.END_OF_COMMAND:
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cmd = self._parse_command(self._buf)
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self._buf = bytes()
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if cmd:
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return cmd
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elif len(self._buf) >= self._max_bufsize:
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self.logger.warning(
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'The received command is too long: length=%d', len(self._buf)
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)
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self._buf = bytes()
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break
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else:
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self._buf += bytes([ch])
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return None
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