1#!/usr/bin/env python
2
3# portable serial port access with python
4# this is a wrapper module for different platform implementations
5#
6# (C) 2001-2010 Chris Liechti <cliechti@gmx.net>
7# this is distributed under a free software license, see license.txt
8
9VERSION = '2.7'
10
11import sys
12
13if sys.platform == 'cli':
14    from serial.serialcli import *
15else:
16    import os
17    # chose an implementation, depending on os
18    if os.name == 'nt': #sys.platform == 'win32':
19        from serial.serialwin32 import *
20    elif os.name == 'posix':
21        from serial.serialposix import *
22    elif os.name == 'java':
23        from serial.serialjava import *
24    else:
25        raise ImportError("Sorry: no implementation for your platform ('%s') available" % (os.name,))
26
27
28protocol_handler_packages = [
29        'serial.urlhandler',
30        ]
31
32def serial_for_url(url, *args, **kwargs):
33    """\
34    Get an instance of the Serial class, depending on port/url. The port is not
35    opened when the keyword parameter 'do_not_open' is true, by default it
36    is. All other parameters are directly passed to the __init__ method when
37    the port is instantiated.
38
39    The list of package names that is searched for protocol handlers is kept in
40    ``protocol_handler_packages``.
41
42    e.g. we want to support a URL ``foobar://``. A module
43    ``my_handlers.protocol_foobar`` is provided by the user. Then
44    ``protocol_handler_packages.append("my_handlers")`` would extend the search
45    path so that ``serial_for_url("foobar://"))`` would work.
46    """
47    # check remove extra parameter to not confuse the Serial class
48    do_open = 'do_not_open' not in kwargs or not kwargs['do_not_open']
49    if 'do_not_open' in kwargs: del kwargs['do_not_open']
50    # the default is to use the native version
51    klass = Serial   # 'native' implementation
52    # check port type and get class
53    try:
54        url_nocase = url.lower()
55    except AttributeError:
56        # it's not a string, use default
57        pass
58    else:
59        if '://' in url_nocase:
60            protocol = url_nocase.split('://', 1)[0]
61            for package_name in protocol_handler_packages:
62                module_name = '%s.protocol_%s' % (package_name, protocol,)
63                try:
64                    handler_module = __import__(module_name)
65                except ImportError:
66                    pass
67                else:
68                    klass = sys.modules[module_name].Serial
69                    break
70            else:
71                raise ValueError('invalid URL, protocol %r not known' % (protocol,))
72        else:
73            klass = Serial   # 'native' implementation
74    # instantiate and open when desired
75    instance = klass(None, *args, **kwargs)
76    instance.port = url
77    if do_open:
78        instance.open()
79    return instance
80