Current File : //usr/lib/python3/dist-packages/serial/__init__.py
#!/usr/bin/env python
#
# This is a wrapper module for different platform implementations
#
# This file is part of pySerial. https://github.com/pyserial/pyserial
# (C) 2001-2020 Chris Liechti <cliechti@gmx.net>
#
# SPDX-License-Identifier: BSD-3-Clause
from __future__ import absolute_import
import sys
import importlib
from serial.serialutil import *
#~ SerialBase, SerialException, to_bytes, iterbytes
__version__ = '3.5'
VERSION = __version__
# pylint: disable=wrong-import-position
if sys.platform == 'cli':
from serial.serialcli import Serial
else:
import os
# chose an implementation, depending on os
if os.name == 'nt': # sys.platform == 'win32':
from serial.serialwin32 import Serial
elif os.name == 'posix':
from serial.serialposix import Serial, PosixPollSerial, VTIMESerial # noqa
elif os.name == 'java':
from serial.serialjava import Serial
else:
raise ImportError("Sorry: no implementation for your platform ('{}') available".format(os.name))
protocol_handler_packages = [
'serial.urlhandler',
]
def serial_for_url(url, *args, **kwargs):
"""\
Get an instance of the Serial class, depending on port/url. The port is not
opened when the keyword parameter 'do_not_open' is true, by default it
is. All other parameters are directly passed to the __init__ method when
the port is instantiated.
The list of package names that is searched for protocol handlers is kept in
``protocol_handler_packages``.
e.g. we want to support a URL ``foobar://``. A module
``my_handlers.protocol_foobar`` is provided by the user. Then
``protocol_handler_packages.append("my_handlers")`` would extend the search
path so that ``serial_for_url("foobar://"))`` would work.
"""
# check and remove extra parameter to not confuse the Serial class
do_open = not kwargs.pop('do_not_open', False)
# the default is to use the native implementation
klass = Serial
try:
url_lowercase = url.lower()
except AttributeError:
# it's not a string, use default
pass
else:
# if it is an URL, try to import the handler module from the list of possible packages
if '://' in url_lowercase:
protocol = url_lowercase.split('://', 1)[0]
module_name = '.protocol_{}'.format(protocol)
for package_name in protocol_handler_packages:
try:
importlib.import_module(package_name)
handler_module = importlib.import_module(module_name, package_name)
except ImportError:
continue
else:
if hasattr(handler_module, 'serial_class_for_url'):
url, klass = handler_module.serial_class_for_url(url)
else:
klass = handler_module.Serial
break
else:
raise ValueError('invalid URL, protocol {!r} not known'.format(protocol))
# instantiate and open when desired
instance = klass(None, *args, **kwargs)
instance.port = url
if do_open:
instance.open()
return instance
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