Source code for

This Listener simply prints to stdout / the terminal or a file.

import logging

from typing import Optional, TextIO, Union, Any, cast

from ..message import Message
from .generic import MessageWriter
from ..typechecking import StringPathLike

log = logging.getLogger("")

[docs]class Printer(MessageWriter): """ The Printer class is a subclass of :class:`~can.Listener` which simply prints any messages it receives to the terminal (stdout). A message is turned into a string using :meth:`~can.Message.__str__`. :attr write_to_file: `True` if this instance prints to a file instead of standard out """ file: Optional[TextIO] def __init__( self, file: Optional[Union[StringPathLike, TextIO]] = None, append: bool = False, *args: Any, **kwargs: Any ) -> None: """ :param file: An optional path-like object or a file-like object to "print" to instead of writing to standard out (stdout). If this is a file-like object, is has to be opened in text write mode, not binary write mode. :param append: If set to `True` messages, are appended to the file, else the file is truncated """ self.write_to_file = file is not None mode = "a" if append else "w" super().__init__(file, mode=mode)
[docs] def on_message_received(self, msg: Message) -> None: if self.write_to_file: cast(TextIO, self.file).write(str(msg) + "\n") else: print(msg)
[docs] def file_size(self) -> int: """Return an estimate of the current file size in bytes.""" if self.file is not None: return self.file.tell() return 0