# coding: utf-8
"""
This Listener simply prints to stdout / the terminal or a file.
"""
import logging
from can.listener import Listener
from .generic import BaseIOHandler
log = logging.getLogger("can.io.printer")
[docs]class Printer(BaseIOHandler, Listener):
"""
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 bool write_to_file: `True` iff this instance prints to a file instead of
standard out
"""
def __init__(self, file=None, append=False):
"""
:param file: an optional path-like object or as file-like object to "print"
to instead of writing to standard out (stdout)
If this is a file-like object, is has to opened in text
write mode, not binary write mode.
:param bool 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):
if self.write_to_file:
self.file.write(str(msg) + "\n")
else:
print(msg)