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# coding: utf-8
"""
This module contains handling for CSV (comma separated values) files.
TODO: CAN FD messages are not yet supported.
TODO: This module could use https://docs.python.org/2/library/csv.html#module-csv
to allow different delimiters for writing, special escape chars to circumvent
the base64 encoding and use csv.Sniffer to automatically deduce the delimiters
of a CSV file.
"""
from __future__ import absolute_import
from base64 import b64encode, b64decode
from can.message import Message
from can.listener import Listener
from .generic import BaseIOHandler
class CSVWriter(BaseIOHandler, Listener):
"""Writes a comma separated text file with a line for
each message. Includes a header line.
The columns are as follows:
================ ======================= ===============
name of column format description example
================ ======================= ===============
timestamp decimal float 1483389946.197
arbitration_id hex 0x00dadada
extended 1 == True, 0 == False 1
remote 1 == True, 0 == False 0
error 1 == True, 0 == False 0
dlc int 6
data base64 encoded WzQyLCA5XQ==
================ ======================= ===============
Each line is terminated with a platform specific line separator.
"""
def __init__(self, file, append=False):
"""
:param file: a path-like object or a file-like object to write to.
If this is a file-like object, is has to open in text
write mode, not binary write mode.
:param bool append: if set to `True` messages are appended to
the file and no header line is written, else
the file is truncated and starts with a newly
written header line
"""
mode = 'a' if append else 'w'
super(CSVWriter, self).__init__(file, mode=mode)
# Write a header row
if not append:
self.file.write("timestamp,arbitration_id,extended,remote,error,dlc,data\n")
def on_message_received(self, msg):
row = ','.join([
repr(msg.timestamp), # cannot use str() here because that is rounding
hex(msg.arbitration_id),
'1' if msg.is_extended_id else '0',
'1' if msg.is_remote_frame else '0',
'1' if msg.is_error_frame else '0',
str(msg.dlc),
b64encode(msg.data).decode('utf8')
])
self.file.write(row)
self.file.write('\n')
class CSVReader(BaseIOHandler):
"""Iterator over CAN messages from a .csv file that was
generated by :class:`~can.CSVWriter` or that uses the same
format as described there. Assumes that there is a header
and thus skips the first line.
Any line separator is accepted.
"""
def __init__(self, file):
"""
:param file: a path-like object or as file-like object to read from
If this is a file-like object, is has to opened in text
read mode, not binary read mode.
"""
super(CSVReader, self).__init__(file, mode='r')
def __iter__(self):
# skip the header line
next(self.file)
for line in self.file:
timestamp, arbitration_id, extended, remote, error, dlc, data = line.split(',')
yield Message(
timestamp=float(timestamp),
is_remote_frame=(remote == '1'),
is_extended_id=(extended == '1'),
is_error_frame=(error == '1'),
arbitration_id=int(arbitration_id, base=16),
dlc=int(dlc),
data=b64decode(data),
)
self.stop()
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