1

#!/usr/bin/env python

     2

# -*- coding: utf-8 -*-

     3

     4

# This file is part of Beremiz, a Integrated Development Environment for

     5

# programming IEC 61131-3 automates supporting plcopen standard and CanFestival.

     6

#

     7

# Copyright (C) 2007: Edouard TISSERANT and Laurent BESSARD

     8

#

     9

# See COPYING file for copyrights details.

    10

#

    11

# This program is free software; you can redistribute it and/or

    12

# modify it under the terms of the GNU General Public License

    13

# as published by the Free Software Foundation; either version 2

    14

# of the License, or (at your option) any later version.

    15

#

    16

# This program is distributed in the hope that it will be useful,

    17

# but WITHOUT ANY WARRANTY; without even the implied warranty of

    18

# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

    19

# GNU General Public License for more details.

    20

#

    21

# You should have received a copy of the GNU General Public License

    22

# along with this program; if not, write to the Free Software

    23

# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.

    24

    25

    26

from __future__ import absolute_import

    27

from __future__ import print_function

    28

import traceback

    29

from time import sleep

    30

import copy

    31

import socket

    32

import os.path

    33

    34

import Pyro

    35

import Pyro.core

    36

import Pyro.util

    37

from Pyro.errors import PyroError

    38

    39

service_type = '_PYRO._tcp.local.'

    40

# this module attribute contains a list of DNS-SD (Zeroconf) service types

    41

# supported by this connector confnode.

    42

#

    43

# for connectors that do not support DNS-SD, this attribute can be omitted

    44

# or set to an empty list.

    45

    46

    47

def PYRO_connector_factory(uri, confnodesroot):

    48

    """

    49

    This returns the connector to Pyro style PLCobject

    50

    """

    51

    confnodesroot.logger.write(_("PYRO connecting to URI : %s\n") % uri)

    52

    53

    servicetype, location = uri.split("://")

    54

    if servicetype == "PYROS":

    61

            confnodesroot.logger.write_error(

    63

            return None

    65

    else:

    66

        schemename = "PYROLOC"

    68

    if location.find(service_type) != -1:

    69

        try:

    70

            from zeroconf import Zeroconf

    71

            r = Zeroconf()

    72

            i = r.get_service_info(service_type, location)

    73

            if i is None:

    74

                raise Exception("'%s' not found" % location)

    75

            ip = str(socket.inet_ntoa(i.address))

    76

            port = str(i.port)

    77

            newlocation = ip + ':' + port

    78

            confnodesroot.logger.write(_("'{a1}' is located at {a2}\n").format(a1=location, a2=newlocation))

    79

            location = newlocation

    80

            r.close()

    81

        except Exception:

    82

            confnodesroot.logger.write_error(_("MDNS resolution failure for '%s'\n") % location)

    83

            confnodesroot.logger.write_error(traceback.format_exc())

    84

            return None

    85

    86

    # Try to get the proxy object

    87

    try:

    88

        RemotePLCObjectProxy = Pyro.core.getAttrProxyForURI(schemename + "://" + location + "/PLCObject")

    89

    except Exception:

    90

        confnodesroot.logger.write_error(_("Connection to '%s' failed.\n") % location)

    91

        confnodesroot.logger.write_error(traceback.format_exc())

    92

        return None

    93

    94

    def PyroCatcher(func, default=None):

    95

        """

    96

        A function that catch a Pyro exceptions, write error to logger

    97

        and return default value when it happen

    98

        """

    99

        def catcher_func(*args, **kwargs):

   100

            try:

   101

                return func(*args, **kwargs)

   102

            except Pyro.errors.ConnectionClosedError, e:

   103

                confnodesroot.logger.write_error(_("Connection lost!\n"))

   104

                confnodesroot._SetConnector(None)

   105

            except Pyro.errors.ProtocolError, e:

   106

                confnodesroot.logger.write_error(_("Pyro exception: %s\n") % e)

   107

            except Exception, e:

   108

                # confnodesroot.logger.write_error(traceback.format_exc())

   109

                errmess = ''.join(Pyro.util.getPyroTraceback(e))

   110

                confnodesroot.logger.write_error(errmess + "\n")

   111

                print(errmess)

   112

                confnodesroot._SetConnector(None)

   113

            return default

   114

        return catcher_func

   115

   116

    # Check connection is effective.

   117

    # lambda is for getattr of GetPLCstatus to happen inside catcher

   118

    if PyroCatcher(RemotePLCObjectProxy.GetPLCstatus)() is None:

   119

        confnodesroot.logger.write_error(_("Cannot get PLC status - connection failed.\n"))

   120

        return None

   121

   122

    _special_return_funcs = {

   123

        "StartPLC": False,

   124

        "GetTraceVariables": ("Broken", None),

   125

        "GetPLCstatus": ("Broken", None),

   126

        "RemoteExec": (-1, "RemoteExec script failed!")

   127

    }

   128

   129

    class PyroProxyProxy(object):

   130

        """

   131

        A proxy proxy class to handle Beremiz Pyro interface specific behavior.

   132

        And to put Pyro exception catcher in between caller and Pyro proxy

   133

        """

   134

        def __getattr__(self, attrName):

   135

            member = self.__dict__.get(attrName, None)

   136

            if member is None:

   137

                def my_local_func(*args, **kwargs):

   138

                    return RemotePLCObjectProxy.__getattr__(attrName)(*args, **kwargs)

   139

                member = PyroCatcher(my_local_func, _special_return_funcs.get(attrName, None))

   140

                self.__dict__[attrName] = member

   141

            return member

   142

   143

    return PyroProxyProxy()