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#!/usr/bin/env python

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

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# This file is part of Beremiz runtime.

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#

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# Copyright (C) 2020: Mario de Sousa

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#

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# See COPYING.Runtime file for copyrights details.

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#

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

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

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# License as published by the Free Software Foundation; either

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# version 2.1 of the License, or (at your option) any later version.

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

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

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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

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# Lesser General Public License for more details.

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

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

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

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##############################################################################################

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# This file implements an extension to the web server embedded in the Beremiz_service.py     #

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# runtime manager (webserver is in runtime/NevowServer.py).                                  #

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#                                                                                            #

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# The extension implemented in this file allows for runtime configuration                    #

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# of Modbus plugin parameters                                                                #

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##############################################################################################

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import json

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import os

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import ctypes

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import string

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import hashlib

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from formless import annotate, webform

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import runtime.NevowServer as NS

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# Directory in which to store the persistent configurations

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# Should be a directory that does not get wiped on reboot!

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_ModbusConfFiledir = WorkingDir

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# List of all Web Extension Setting nodes we are handling.

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# One WebNode each for:

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#   - Modbus TCP client 

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#   - Modbus TCP server

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#   - Modbus RTU client

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#   - Modbus RTU slave

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# configured in the loaded PLC (i.e. the .so file loaded into memory)

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# Each entry will be a dictionary. See _AddWebNode() for the details

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# of the data structure in each entry.

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_WebNodeList = []

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class MB_StrippedString(annotate.String):

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    def __init__(self, *args, **kwargs):

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        annotate.String.__init__(self, strip = True, *args, **kwargs)

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class MB_StopBits(annotate.Choice):

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    _choices = [0, 1, 2]

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    def coerce(self, val, configurable):

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        return int(val)

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    def __init__(self, *args, **kwargs):

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        annotate.Choice.__init__(self, choices = self._choices, *args, **kwargs)

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class MB_Baud(annotate.Choice):

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    _choices = [110, 300, 600, 1200, 2400, 4800, 9600, 19200, 38400, 57600, 115200]

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    def coerce(self, val, configurable):

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        return int(val)

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    def __init__(self, *args, **kwargs):

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        annotate.Choice.__init__(self, choices = self._choices, *args, **kwargs)

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class MB_Parity(annotate.Choice):

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    # For more info on what this class really does, have a look at the code in

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    # file twisted/nevow/annotate.py

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    # grab this code from $git clone https://github.com/twisted/nevow/

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    # 

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    # Warning: do _not_ name this variable choice[] without underscore, as that name is

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    # already used for another similar variable by the underlying class annotate.Choice

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    _choices = [  0,      1,      2  ]

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    _label   = ["none", "odd", "even"]

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    def choice_to_label(self, key):

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        #PLCObject.LogMessage("Modbus web server extension::choice_to_label()  " + str(key))

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        return self._label[key]

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    def coerce(self, val, configurable):

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        """Coerce a value with the help of an object, which is the object

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        we are configuring.

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        """

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        # Basically, make sure the value the user introduced is valid, and transform

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        # into something that is valid if necessary or mark it as an error 

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        # (by raising an exception ??).

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        #

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        # We are simply using this functions to transform the input value (a string)

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        # into an integer. Note that although the available options are all

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        # integers (0, 1 or 2), even though what is shown on the user interface

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        # are actually strings, i.e. the labels), these parameters are for some 

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        # reason being parsed as strings, so we need to map them back to an

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        # integer.

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        #

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        #PLCObject.LogMessage("Modbus web server extension::coerce  " + val )

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        return int(val)

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    def __init__(self, *args, **kwargs):

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        annotate.Choice.__init__(self, 

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                                 choices   = self._choices,

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                                 stringify = self.choice_to_label,

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                                 *args, **kwargs)

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# Parameters we will need to get from the C code, but that will not be shown

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# on the web interface. Common to all modbus entry types (client/server, tcp/rtu/ascii)

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#

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# The annotate type entry is basically useless and is completely ignored.

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# We kee that entry so that this list can later be correctly merged with the

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# following lists...

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General_parameters = [

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    #    param. name       label                        ctype type         annotate type

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    # (C code var name)   (used on web interface)      (C data type)       (web data type)

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    #                                                                      (annotate.String,

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    #                                                                       annotate.Integer, ...)

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    ("config_name"      , _("")                      , ctypes.c_char_p,    annotate.String),

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    ("addr_type"        , _("")                      , ctypes.c_char_p,    annotate.String)

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    ]                                                                      

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# Parameters we will need to get from the C code, and that _will_ be shown

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# on the web interface.

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TCPclient_parameters = [                                                   

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    #    param. name       label                        ctype type         annotate type

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    # (C code var name)   (used on web interface)      (C data type)       (web data type)

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    #                                                                      (annotate.String,

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    #                                                                       annotate.Integer, ...)

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    ("host"             , _("Remote IP Address")     , ctypes.c_char_p,    MB_StrippedString),

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    ("port"             , _("Remote Port Number")    , ctypes.c_char_p,    MB_StrippedString),

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    ("comm_period"      , _("Invocation Rate (ms)")  , ctypes.c_ulonglong, annotate.Integer )

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    ]

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RTUclient_parameters = [                                                   

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    #    param. name       label                        ctype type         annotate type

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    # (C code var name)   (used on web interface)      (C data type)       (web data type)

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    #                                                                      (annotate.String,

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    #                                                                       annotate.Integer, ...)

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    ("device"           , _("Serial Port")           , ctypes.c_char_p,    MB_StrippedString),

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    ("baud"             , _("Baud Rate")             , ctypes.c_int,       MB_Baud         ),

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    ("parity"           , _("Parity")                , ctypes.c_int,       MB_Parity       ),

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    ("stop_bits"        , _("Stop Bits")             , ctypes.c_int,       MB_StopBits     ),

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    ("comm_period"      , _("Invocation Rate (ms)")  , ctypes.c_ulonglong, annotate.Integer)

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    ]

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TCPserver_parameters = [                                                   

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    #    param. name       label                        ctype type         annotate type

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    # (C code var name)   (used on web interface)      (C data type)       (web data type)

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    #                                                                      (annotate.String,

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    #                                                                       annotate.Integer, ...)

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    ("host"             , _("Local IP Address")      , ctypes.c_char_p,    MB_StrippedString),

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    ("port"             , _("Local Port Number")     , ctypes.c_char_p,    MB_StrippedString),

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    ("slave_id"         , _("Slave ID")              , ctypes.c_ubyte,     annotate.Integer )

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    ]

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RTUslave_parameters = [                                                   

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    #    param. name       label                        ctype type         annotate type

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    # (C code var name)   (used on web interface)      (C data type)       (web data type)

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    #                                                                      (annotate.String,

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    #                                                                       annotate.Integer, ...)

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    ("device"           , _("Serial Port")           , ctypes.c_char_p,    MB_StrippedString),

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    ("baud"             , _("Baud Rate")             , ctypes.c_int,       MB_Baud         ),

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    ("parity"           , _("Parity")                , ctypes.c_int,       MB_Parity       ),

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    ("stop_bits"        , _("Stop Bits")             , ctypes.c_int,       MB_StopBits     ),

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    ("slave_id"         , _("Slave ID")              , ctypes.c_ubyte,     annotate.Integer)

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    ]

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# Dictionary containing List of Web viewable parameters

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# Note: the dictionary key must be the same as the string returned by the 

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# __modbus_get_ClientNode_addr_type()

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# __modbus_get_ServerNode_addr_type()

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# functions implemented in C (see modbus/mb_runtime.c)

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_client_WebParamListDict = {}

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_client_WebParamListDict["tcp"  ] = TCPclient_parameters

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_client_WebParamListDict["rtu"  ] = RTUclient_parameters

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_client_WebParamListDict["ascii"] = []  # (Note: ascii not yet implemented in Beremiz modbus plugin)

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_server_WebParamListDict = {}

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_server_WebParamListDict["tcp"  ] = TCPserver_parameters

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_server_WebParamListDict["rtu"  ] = RTUslave_parameters

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_server_WebParamListDict["ascii"] = []  # (Note: ascii not yet implemented in Beremiz modbus plugin)

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WebParamListDictDict = {}

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WebParamListDictDict['client'] = _client_WebParamListDict

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WebParamListDictDict['server'] = _server_WebParamListDict

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def _SetModbusSavedConfiguration(WebNode_id, newConfig):

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    """ Stores a dictionary in a persistant file containing the Modbus parameter configuration """

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    WebNode_entry = _WebNodeList[WebNode_id]

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    if WebNode_entry["DefaultConfiguration"] == newConfig:

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        _DelModbusSavedConfiguration(WebNode_id)

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        WebNode_entry["ModbusSavedConfiguration"] = None

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    else:

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        # Add the addr_type and node_type to the data that will be saved to file

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        # This allows us to confirm the saved data contains the correct addr_type

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        # when loading from file

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        save_info = {}

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        save_info["addr_type"] = WebNode_entry["addr_type"]

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        save_info["node_type"] = WebNode_entry["node_type"]

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        save_info["config"   ] = newConfig

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        filename = WebNode_entry["filename"]

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        with open(os.path.realpath(filename), 'w') as f:

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            json.dump(save_info, f, sort_keys=True, indent=4)

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        WebNode_entry["ModbusSavedConfiguration"] = newConfig

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def _DelModbusSavedConfiguration(WebNode_id):

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    """ Deletes the file cotaining the persistent Modbus configuration """

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    filename = _WebNodeList[WebNode_id]["filename"]

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    if os.path.exists(filename):

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        os.remove(filename)

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def _GetModbusSavedConfiguration(WebNode_id):

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    """

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    Returns a dictionary containing the Modbus parameter configuration

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    that was last saved to file. If no file exists, or file contains 

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    wrong addr_type (i.e. 'tcp', 'rtu' or 'ascii' -> does not match the

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    addr_type of the WebNode_id), then return None

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    """

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    filename = _WebNodeList[WebNode_id]["filename"]

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    try:

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        #if os.path.isfile(filename):

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        save_info = json.load(open(os.path.realpath(filename)))

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    except Exception:    

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        return None

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    if save_info["addr_type"] != _WebNodeList[WebNode_id]["addr_type"]:

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        return None

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    if save_info["node_type"] != _WebNodeList[WebNode_id]["node_type"]:

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        return None

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    if "config" not in save_info:

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        return None

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    saved_config = save_info["config"]

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    #if _CheckConfiguration(saved_config):

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    #    return saved_config

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    #else:

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    #    return None

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    return saved_config

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def _GetModbusPLCConfiguration(WebNode_id):

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    """

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    Returns a dictionary containing the current Modbus parameter configuration

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    stored in the C variables in the loaded PLC (.so file)

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    """

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    current_config = {}

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    C_node_id      = _WebNodeList[WebNode_id]["C_node_id"]

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    WebParamList   = _WebNodeList[WebNode_id]["WebParamList"]

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    GetParamFuncs  = _WebNodeList[WebNode_id]["GetParamFuncs"]

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    for par_name, x1, x2, x3 in WebParamList:

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        value = GetParamFuncs[par_name](C_node_id)

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        if value is not None:

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            current_config[par_name] = value

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    return current_config

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def _SetModbusPLCConfiguration(WebNode_id, newconfig):

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    """

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    Stores the Modbus parameter configuration into the

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    the C variables in the loaded PLC (.so file)

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    """

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    C_node_id      = _WebNodeList[WebNode_id]["C_node_id"]

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    SetParamFuncs  = _WebNodeList[WebNode_id]["SetParamFuncs"]

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    for par_name in newconfig:

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        value = newconfig[par_name]

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        if value is not None:

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            SetParamFuncs[par_name](C_node_id, value)

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def _GetModbusWebviewConfigurationValue(ctx, WebNode_id, argument):

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    """

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    Callback function, called by the web interface (NevowServer.py)

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    to fill in the default value of each parameter of the web form

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    Note that the real callback function is a dynamically created function that

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    will simply call this function to do the work. It will also pass the WebNode_id 

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    as a parameter.

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    """    

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    try:

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        return _WebNodeList[WebNode_id]["WebviewConfiguration"][argument.name]

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    except Exception:

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        return ""

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def OnModbusButtonSave(**kwargs):

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    """

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    Function called when user clicks 'Save' button in web interface

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    The function will configure the Modbus plugin in the PLC with the values

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    specified in the web interface. However, values must be validated first!

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    Note that this function does not get called directly. The real callback

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    function is the dynamic __OnButtonSave() function, which will add the 

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    "WebNode_id" argument, and call this function to do the work.

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    """

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    #PLCObject.LogMessage("Modbus web server extension::OnModbusButtonSave()  Called")

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    newConfig    = {}

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    WebNode_id   =  kwargs.get("WebNode_id", None)

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    WebParamList = _WebNodeList[WebNode_id]["WebParamList"]

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    for par_name, x1, x2, x3 in WebParamList:

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        value = kwargs.get(par_name, None)

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        if value is not None:

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            newConfig[par_name] = value

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    # First check if configuration is OK.

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    # Note that this is not currently required, as we use drop down choice menus

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    # for baud, parity and sop bits, so the values should always be correct!

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    #if not _CheckWebConfiguration(newConfig):

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    #    return

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    # store to file the new configuration so that 

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    # we can recoup the configuration the next time the PLC

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    # has a cold start (i.e. when Beremiz_service.py is retarted)

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    _SetModbusSavedConfiguration(WebNode_id, newConfig)

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    # Configure PLC with the current Modbus parameters

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    _SetModbusPLCConfiguration(WebNode_id, newConfig)

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    # Update the viewable configuration

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    # The PLC may have coerced the values on calling _SetModbusPLCConfiguration()

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    # so we do not set it directly to newConfig

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    _WebNodeList[WebNode_id]["WebviewConfiguration"] = _GetModbusPLCConfiguration(WebNode_id)

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def OnModbusButtonReset(**kwargs):

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    """

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    Function called when user clicks 'Delete' button in web interface

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    The function will delete the file containing the persistent

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    Modbus configution

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    """

   387

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    WebNode_id = kwargs.get("WebNode_id", None)

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    # Delete the file

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    _DelModbusSavedConfiguration(WebNode_id)

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    # Set the current configuration to the default (hardcoded in C)

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    new_config = _WebNodeList[WebNode_id]["DefaultConfiguration"]

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    _SetModbusPLCConfiguration(WebNode_id, new_config)

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    #Update the webviewconfiguration

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    _WebNodeList[WebNode_id]["WebviewConfiguration"] = new_config

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    # Reset ModbusSavedConfiguration

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    _WebNodeList[WebNode_id]["ModbusSavedConfiguration"] = None

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def _AddWebNode(C_node_id, node_type, GetParamFuncs, SetParamFuncs):

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    """

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    Load from the compiled code (.so file, aloready loaded into memmory)

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    the configuration parameters of a specific Modbus plugin node.

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    This function works with both client and server nodes, depending on the

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    Get/SetParamFunc dictionaries passed to it (either the client or the server

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    node versions of the Get/Set functions)

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    """

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    WebNode_entry = {}

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    # Get the config_name from the C code...

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    config_name = GetParamFuncs["config_name"](C_node_id)

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    # Get the addr_type from the C code...

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    # addr_type will be one of "tcp", "rtu" or "ascii"

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    addr_type   = GetParamFuncs["addr_type"  ](C_node_id)   

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    # For some operations we cannot use the config name (e.g. filename to store config)

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    # because the user may be using characters that are invalid for that purpose ('/' for

   424

    # example), so we create a hash of the config_name, and use that instead.

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    config_hash = hashlib.md5(config_name).hexdigest()

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    #PLCObject.LogMessage("Modbus web server extension::_AddWebNode("+str(C_node_id)+") config_name="+config_name)

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    # Add the new entry to the global list

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    # Note: it is OK, and actually necessary, to do this _before_ seting all the parameters in WebNode_entry

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    #       WebNode_entry will be stored as a reference, so we can later insert parameters at will.

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    global _WebNodeList

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    _WebNodeList.append(WebNode_entry)

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    WebNode_id = len(_WebNodeList) - 1

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    # store all WebNode relevant data for future reference

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    #

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    # Note that "WebParamList" will reference one of:

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    #  - TCPclient_parameters, TCPserver_parameters, RTUclient_parameters, RTUslave_parameters

   440

    WebNode_entry["C_node_id"    ] = C_node_id

   441

    WebNode_entry["config_name"  ] = config_name 

   442

    WebNode_entry["config_hash"  ] = config_hash

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    WebNode_entry["filename"     ] = os.path.join(_ModbusConfFiledir, "Modbus_config_" + config_hash + ".json")

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    WebNode_entry["GetParamFuncs"] = GetParamFuncs

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    WebNode_entry["SetParamFuncs"] = SetParamFuncs

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    WebNode_entry["WebParamList" ] = WebParamListDictDict[node_type][addr_type] 

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    WebNode_entry["addr_type"    ] = addr_type  # 'tcp', 'rtu', or 'ascii' (as returned by C function)

   448

    WebNode_entry["node_type"    ] = node_type  # 'client', 'server'

   449

   450

   451

    # Dictionary that contains the Modbus configuration currently being shown

   452

    # on the web interface

   453

    # This configuration will almost always be identical to the current

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    # configuration in the PLC (i.e., the current state stored in the 

   455

    # C variables in the .so file).

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    # The configuration viewed on the web will only be different to the current 

   457

    # configuration when the user edits the configuration, and when

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    # the user asks to save an edited configuration that contains an error.

   459

    WebNode_entry["WebviewConfiguration"] = None

   460

   461

    # Upon PLC load, this Dictionary is initialised with the Modbus configuration

   462

    # hardcoded in the C file

   463

    # (i.e. the configuration inserted in Beremiz IDE when project was compiled)

   464

    WebNode_entry["DefaultConfiguration"] = _GetModbusPLCConfiguration(WebNode_id)

   465

    WebNode_entry["WebviewConfiguration"] = WebNode_entry["DefaultConfiguration"]

   466

   467

    # Dictionary that stores the Modbus configuration currently stored in a file

   468

    # Currently only used to decide whether or not to show the "Delete" button on the

   469

    # web interface (only shown if "ModbusSavedConfiguration" is not None)

   470

    SavedConfig = _GetModbusSavedConfiguration(WebNode_id)

   471

    WebNode_entry["ModbusSavedConfiguration"] = SavedConfig

   472

   473

    if SavedConfig is not None:

   474

        _SetModbusPLCConfiguration(WebNode_id, SavedConfig)

   475

        WebNode_entry["WebviewConfiguration"] = SavedConfig

   476

   477

    # Define the format for the web form used to show/change the current parameters

   478

    # We first declare a dynamic function to work as callback to obtain the default values for each parameter

   479

    # Note: We transform every parameter into a string

   480

    #       This is not strictly required for parameters of type annotate.Integer that will correctly

   481

    #           accept the default value as an Integer python object

   482

    #       This is obviously also not required for parameters of type annotate.String, that are

   483

    #           always handled as strings.

   484

    #       However, the annotate.Choice parameters (and all parameters that derive from it,

   485

    #           sucn as Parity, Baud, etc.) require the default value as a string

   486

    #           even though we store it as an integer, which is the data type expected

   487

    #           by the set_***() C functions in mb_runtime.c

   488

    def __GetWebviewConfigurationValue(ctx, argument):

   489

        return str(_GetModbusWebviewConfigurationValue(ctx, WebNode_id, argument))

   490

   491

    webFormInterface = [(name, web_dtype (label=web_label, default=__GetWebviewConfigurationValue)) 

   492

                    for name, web_label, c_dtype, web_dtype in WebNode_entry["WebParamList"]]

   493

   494

    # Configure the web interface to include the Modbus config parameters

   495

    def __OnButtonSave(**kwargs):

   496

        OnModbusButtonSave(WebNode_id=WebNode_id, **kwargs)

   497

   498

    WebSettings = NS.newExtensionSetting("Modbus #"+ str(WebNode_id), config_hash)

   499

   500

    WebSettings.addSettings(

   501