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#!/usr/bin/env python
# portable serial port access with python
# this is a wrapper module for different platform implementations
#
# (C) 2001-2010 Chris Liechti <cliechti@gmx.net>
# this is distributed under a free software license, see license.txt
VERSION = '2.7'
import sys
if sys.platform == 'cli':
from serial.serialcli import *
else:
import os
# chose an implementation, depending on os
if os.name == 'nt': #sys.platform == 'win32':
from serial.serialwin32 import *
elif os.name == 'posix':
from serial.serialposix import *
elif os.name == 'java':
from serial.serialjava import *
else:
raise ImportError("Sorry: no implementation for your platform ('%s') available" % (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 remove extra parameter to not confuse the Serial class
do_open = 'do_not_open' not in kwargs or not kwargs['do_not_open']
if 'do_not_open' in kwargs: del kwargs['do_not_open']
# the default is to use the native version
klass = Serial # 'native' implementation
# check port type and get class
try:
url_nocase = url.lower()
except AttributeError:
# it's not a string, use default
pass
else:
if '://' in url_nocase:
protocol = url_nocase.split('://', 1)[0]
for package_name in protocol_handler_packages:
module_name = '%s.protocol_%s' % (package_name, protocol,)
try:
handler_module = __import__(module_name)
except ImportError:
pass
else:
klass = sys.modules[module_name].Serial
break
else:
raise ValueError('invalid URL, protocol %r not known' % (protocol,))
else:
klass = Serial # 'native' implementation
# instantiate and open when desired
instance = klass(None, *args, **kwargs)
instance.port = url
if do_open:
instance.open()
return instance
|
