beremiz

Proper fix for error 'object has no attribute 'getSlave' in EtherCAT extension

2018-08-24, Andrey Skvortsov
96ca6b056c55
Proper fix for error 'object has no attribute 'getSlave' in EtherCAT extension

traceback:
File "/home/developer/WorkData/PLC/beremiz/beremiz/IDEFrame.py", line 1433, in OnPouSelectedChanged
window.RefreshView()
File "/home/developer/WorkData/PLC/beremiz/beremiz/etherlab/ConfigEditor.py", line 837, in RefreshView
self.RefreshProcessVariables()
File "/home/developer/WorkData/PLC/beremiz/beremiz/etherlab/ConfigEditor.py", line 886, in RefreshProcessVariables
slaves = self.Controler.GetSlaves(**self.CurrentNodesFilter)
File "/home/developer/WorkData/PLC/beremiz/beremiz/etherlab/EthercatMaster.py", line 341, in GetSlaves
for slave in self.Config.getConfig().getSlave():
:_'lxml.etree._Element'_object_has_no_attribute_'getSlave'

Steps to reproduce problem:

- Add new EtherCAT master
- Add new EthercatNode to the master
- double click on


Revert commit "Dirty fix for error '_object_has_no_attribute_'getSlave' in EtherCAT extension"
[a3ac46366b86a0b237dac93be6b2281ac70b98a8].

The problem was that XML elements (proxy object) in some cases were created using custom XML
classes constructors and lxml.etree.Element() call and live python
patching. This causes that lxml backend doesn't know that custom python class
should be used for these XML elements.
Proxy object can be move/deleted and recreated by lxml
backend at any point in time or this can be done in python by copy/deepcopy operations.
If this happens, then newly created
proxy elements are using default class lxml.etree._Element. And all
custom functionality is lost.

All created XML elements should be always created through corresponding
parser and class lookup callback done by lxml backend.
It's described in more details in lxml documentation:
https://lxml.de/element_classes.html
#!/usr/bin/env python
# -*- coding: utf-8 -*-
# This file is part of Beremiz, a Integrated Development Environment for
# programming IEC 61131-3 automates supporting plcopen standard and CanFestival.
#
# Copyright (C) 2007: Edouard TISSERANT and Laurent BESSARD
# Copyright (C) 2017: Andrey Skvortsov <andrej.skvortzov@gmail.com>
#
# See COPYING file for copyrights details.
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License
# as published by the Free Software Foundation; either version 2
# of the License, or (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
from __future__ import absolute_import
import wx
from graphics.SFC_Objects import SFC_Transition
from dialogs.BlockPreviewDialog import BlockPreviewDialog
# -------------------------------------------------------------------------------
# Set Transition Parameters Dialog
# -------------------------------------------------------------------------------
class SFCTransitionDialog(BlockPreviewDialog):
"""
Class that implements a dialog for defining parameters of a transition graphic
element
"""
def __init__(self, parent, controller, tagname, connection=True):
"""
Constructor
@param parent: Parent wx.Window of dialog for modal
@param controller: Reference to project controller
@param tagname: Tagname of project POU edited
@param connection: True if transition value can be defined by a
connection (default: True)
"""
BlockPreviewDialog.__init__(self, parent, controller, tagname,
title=_('Edit transition'))
# Init common sizers
self._init_sizers(2, 0, 8, None, 2, 1)
# Create label for transition type
type_label = wx.StaticText(self, label=_('Type:'))
self.LeftGridSizer.AddWindow(type_label, flag=wx.GROW)
# Create combo box for selecting reference value
reference = wx.ComboBox(self, style=wx.CB_READONLY)
reference.Append("")
for transition in controller.GetEditedElementTransitions(tagname):
reference.Append(transition)
self.Bind(wx.EVT_COMBOBOX, self.OnReferenceChanged, reference)
# Create Text control for defining inline value
inline = wx.TextCtrl(self)
self.Bind(wx.EVT_TEXT, self.OnInlineChanged, inline)
# Create radio buttons for selecting power rail type
self.TypeRadioButtons = {}
first = True
for type, label, control in [('reference', _('Reference'), reference),
('inline', _('Inline'), inline),
('connection', _('Connection'), None)]:
radio_button = wx.RadioButton(self, label=label,
style=(wx.RB_GROUP if first else 0))
radio_button.SetValue(first)
self.Bind(wx.EVT_RADIOBUTTON, self.OnTypeChanged, radio_button)
self.LeftGridSizer.AddWindow(radio_button, flag=wx.GROW)
if control is not None:
control.Enable(first)
self.LeftGridSizer.AddWindow(control, flag=wx.GROW)
self.TypeRadioButtons[type] = (radio_button, control)
first = False
# Create label for transition priority
priority_label = wx.StaticText(self, label=_('Priority:'))
self.LeftGridSizer.AddWindow(priority_label, flag=wx.GROW)
# Create spin control for defining priority value
self.Priority = wx.SpinCtrl(self, min=0, style=wx.SP_ARROW_KEYS)
self.Bind(wx.EVT_TEXT, self.OnPriorityChanged, self.Priority)
self.LeftGridSizer.AddWindow(self.Priority, flag=wx.GROW)
# Add preview panel and associated label to sizers
self.RightGridSizer.AddWindow(self.PreviewLabel, flag=wx.GROW)
self.RightGridSizer.AddWindow(self.Preview, flag=wx.GROW)
# Add buttons sizer to sizers
self.MainSizer.AddSizer(
self.ButtonSizer, border=20,
flag=wx.ALIGN_RIGHT | wx.BOTTOM | wx.LEFT | wx.RIGHT)
self.Fit()
# Reference radio button is default control having keyboard focus
self.TypeRadioButtons["reference"][0].SetFocus()
def GetTransitionType(self):
"""
Return type selected for SFC transition and associated value
@return: Type selected and associated value (None if no value)
"""
# Go through radio buttons and return type and value associated to the
# one that is selected
for type, (radio, control) in self.TypeRadioButtons.iteritems():
if radio.GetValue():
if isinstance(control, wx.ComboBox):
return type, control.GetStringSelection()
elif isinstance(control, wx.TextCtrl):
return type, control.GetValue()
else:
return type, None
return None, None
def SetValues(self, values):
"""
Set default SFC transition parameters
@param values: Transition parameters values
"""
# Extract transition value according to type
type_value = values.get("value", None)
# For each parameters defined, set corresponding control value
for name, value in values.items():
# Parameter is SFC transition priority
if name == "priority":
self.Priority.SetValue(values["priority"])
# Parameter is SFC transition type
elif name == "type":
for type, (radio, control) in self.TypeRadioButtons.iteritems():
radio.SetValue(type == value)
if control is not None:
# Enable associated control to type and set value
control.Enable(type == value)
if type == value:
if isinstance(control, wx.ComboBox):
control.SetStringSelection(type_value)
elif isinstance(control, wx.TextCtrl):
control.ChangeValue(type_value)
# Refresh preview panel
self.RefreshPreview()
def GetValues(self):
"""
Return SFC transition parameters defined in dialog
@return: {parameter_name: parameter_value,...}
"""
values = {"priority": self.Priority.GetValue()}
values["type"], values["value"] = self.GetTransitionType()
values["width"], values["height"] = self.Element.GetSize()
return values
def OnOK(self, event):
"""
Called when dialog OK button is pressed
Test if parameters defined are valid
@param event: wx.Event from OK button
"""
message = None
# Get transition type and value associated
type, value = self.GetTransitionType()
# Test that value associated to type is defined
if type != "connection" and value == "":
message = _("Form isn't complete. %s must be filled!") % type
# Show error message if an error is detected
if message is not None:
self.ShowErrorMessage(message)
else:
# Call BlockPreviewDialog function
BlockPreviewDialog.OnOK(self, event)
def OnTypeChanged(self, event):
"""
Called when transition type changed
@param event: wx.RadioButtonEvent
"""
# Refresh sensibility of control associated to transition types
for _type, (radio, control) in self.TypeRadioButtons.iteritems():
if control is not None:
control.Enable(radio.GetValue())
# Refresh preview panel
self.RefreshPreview()
event.Skip()
def OnReferenceChanged(self, event):
"""
Called when SFC transition reference value changed
@param event: wx.ComboBoxEvent
"""
self.RefreshPreview()
event.Skip()
def OnInlineChanged(self, event):
"""
Called when SFC transition inline value changed
@param event: wx.TextEvent
"""
self.RefreshPreview()
event.Skip()
def OnPriorityChanged(self, event):
"""
Called when block inputs number changed
@param event: wx.SpinEvent
"""
self.RefreshPreview()
event.Skip()
def RefreshPreview(self):
"""
Refresh preview panel of graphic element
Override BlockPreviewDialog function
"""
# Set graphic element displayed, creating a SFC transition
self.Element = SFC_Transition(self.Preview)
self.Element.SetType(*self.GetTransitionType())
self.Element.SetPriority(self.Priority.GetValue())
# Call BlockPreviewDialog function
BlockPreviewDialog.RefreshPreview(self)