79 lines
2.1 KiB
Python
79 lines
2.1 KiB
Python
from abc import ABC, abstractmethod
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import json
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from logging import getLogger, Logger
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class Command(ABC):
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"""
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Base class for application commands.
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"""
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END_OF_COMMAND = b'\x00'
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"""End-of-command marker."""
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def __init__(self, **args) -> None:
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self.args = args
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@property
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def logger(self) -> Logger:
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"""
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The command class logger.
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"""
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return getLogger(self.__class__.__name__)
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@abstractmethod
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def __call__(self, app, *_, **__):
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"""
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Execute the command.
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"""
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raise NotImplementedError()
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def __str__(self) -> str:
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"""
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:return: A JSON representation of the command.
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"""
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return json.dumps(
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{
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'type': 'command',
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'command': self.__class__.__name__,
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'args': self.args,
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}
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)
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def to_bytes(self):
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"""
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:return: A JSON representation of the command.
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"""
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return str(self).encode('utf-8') + self.END_OF_COMMAND
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@classmethod
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def parse(cls, data: bytes) -> "Command":
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"""
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:param data: A JSON representation of the command.
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:raise ValueError: If the data is invalid.
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:return: The command instance or None if the data is invalid.
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"""
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import platypush.commands
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try:
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json_data = json.loads(data.decode('utf-8'))
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except json.JSONDecodeError as e:
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raise ValueError from e
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kind = json_data.pop('type', None)
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if kind != 'command':
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raise ValueError(f'Invalid command type: {kind}')
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command_name = json_data.get('command')
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if not command_name:
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raise ValueError(f'Invalid command name: {command_name}')
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cmd_class = getattr(platypush.commands, command_name, None)
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if not (cmd_class and issubclass(cmd_class, Command)):
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raise ValueError(f'Invalid command class: {command_name}')
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try:
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return cmd_class(**json_data.get('args', {}))
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except Exception as e:
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raise ValueError(e) from e
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