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Diffstat (limited to 'serial/__init__.py')
-rw-r--r-- | serial/__init__.py | 91 |
1 files changed, 91 insertions, 0 deletions
diff --git a/serial/__init__.py b/serial/__init__.py new file mode 100644 index 0000000..caa4de1 --- /dev/null +++ b/serial/__init__.py @@ -0,0 +1,91 @@ +#!/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 |