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
#
# 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 os
import sys
import shutil
from xml.dom import minidom
import wx
import util.paths as paths
from py_ext import PythonFileCTNMixin
class WxGladeHMI(PythonFileCTNMixin):
ConfNodeMethods = [
{
"bitmap": "editWXGLADE",
"name": _("WXGLADE GUI"),
"tooltip": _("Edit a WxWidgets GUI with WXGlade"),
"method": "_editWXGLADE"
},
]
def GetIconName(self):
return "wxGlade"
def ConfNodePath(self):
return paths.AbsDir(__file__)
def _getWXGLADEpath(self, project_path=None):
if project_path is None:
project_path = self.CTNPath()
# define name for wxGlade gui file
return os.path.join(project_path, "hmi.wxg")
def GetWxGladePath(self):
path = None
try:
from wxglade import __file__ as fileName
path = os.path.dirname(fileName)
return path
except ImportError:
pass
defLibDir = "/usr/share/wxglade"
if os.path.isdir(defLibDir):
path = defLibDir
return path
def launch_wxglade(self, options, wait=False):
path = self.GetWxGladePath()
glade = os.path.join(path, 'wxglade.py')
if wx.Platform == '__WXMSW__':
glade = "\"%s\"" % glade
mode = {False: os.P_NOWAIT, True: os.P_WAIT}[wait]
os.spawnv(mode, sys.executable,
["\"%s\"" % sys.executable] + [glade] + options)
def OnCTNSave(self, from_project_path=None):
if from_project_path is not None:
shutil.copyfile(self._getWXGLADEpath(from_project_path),
self._getWXGLADEpath())
return PythonFileCTNMixin.OnCTNSave(self, from_project_path)
def CTNGenerate_C(self, buildpath, locations):
# list containing description of all objects declared in wxglade
hmi_objects = []
# list containing only description of the main frame object
main_frames = []
wxgfile_path = self._getWXGLADEpath()
if os.path.exists(wxgfile_path):
wxgfile = open(wxgfile_path, 'r')
wxgtree = minidom.parse(wxgfile)
wxgfile.close()
for node in wxgtree.childNodes[1].childNodes:
if node.nodeType == wxgtree.ELEMENT_NODE:
name = node.getAttribute("name")
wxglade_object_desc = {
"name": name,
"class": node.getAttribute("class"),
"handlers": [
hnode.firstChild.data for hnode in
node.getElementsByTagName("handler")]}
hmi_objects.append(wxglade_object_desc)
if name == self.CTNName():
main_frames.append(wxglade_object_desc)
hmipyfile_path = os.path.join(self._getBuildPath(), "hmi.py")
if wx.Platform == '__WXMSW__':
wxgfile_path = "\"%s\"" % wxgfile_path
wxghmipyfile_path = "\"%s\"" % hmipyfile_path
else:
wxghmipyfile_path = hmipyfile_path
self.launch_wxglade(
['-o', wxghmipyfile_path, '-g', 'python', wxgfile_path], wait=True)
hmipyfile = open(hmipyfile_path, 'r')
define_hmi = hmipyfile.read().decode('utf-8')
hmipyfile.close()
else:
define_hmi = ""
declare_hmi = "\n".join(["%(name)s = None\n" % x for x in main_frames])
declare_hmi += "\n".join(["\n".join(["%(class)s.%(h)s = %(h)s" %
dict(x, h=h) for h in x['handlers']])
for x in hmi_objects])
global_hmi = ("global %s\n" % ",".join(
[x["name"] for x in main_frames]) if len(main_frames) > 0 else "")
init_hmi = "\n".join(["""\
def OnCloseFrame(evt):
wx.MessageBox(_("Please stop PLC to close"))
%(name)s = %(class)s(None)
%(name)s.Bind(wx.EVT_CLOSE, OnCloseFrame)
%(name)s.Show()
""" % x for x in main_frames])
cleanup_hmi = "\n".join(
["if %(name)s is not None: %(name)s.Destroy()" % x
for x in main_frames])
self.PreSectionsTexts = {
"globals": define_hmi,
"start": global_hmi,
"stop": global_hmi + cleanup_hmi
}
self.PostSectionsTexts = {
"globals": declare_hmi,
"start": init_hmi,
}
if len(main_frames) == 0 and \
len(getattr(self.CodeFile, "start").getanyText().strip()) == 0:
self.GetCTRoot().logger.write_warning(
_("Warning: WxGlade HMI has no object with name identical to extension name, and no python code is provided in start section to create object.\n"))
return PythonFileCTNMixin.CTNGenerate_C(self, buildpath, locations)
def _editWXGLADE(self):
wxg_filename = self._getWXGLADEpath()
open_wxglade = True
if not self.GetCTRoot().CheckProjectPathPerm():
dialog = wx.MessageDialog(self.GetCTRoot().AppFrame,
_("You don't have write permissions.\nOpen wxGlade anyway ?"),
_("Open wxGlade"),
wx.YES_NO | wx.ICON_QUESTION)
open_wxglade = dialog.ShowModal() == wx.ID_YES
dialog.Destroy()
if open_wxglade:
if not os.path.exists(wxg_filename):
hmi_name = self.BaseParams.getName()
open(wxg_filename, "w").write("""<?xml version="1.0"?>
<application path="" name="" class="" option="0" language="python" top_window="%(name)s" encoding="UTF-8" use_gettext="0" overwrite="0" use_new_namespace="1" for_version="2.8" is_template="0">
<object class="%(class)s" name="%(name)s" base="EditFrame">
<style>wxDEFAULT_FRAME_STYLE</style>
<title>frame_1</title>
<object class="wxBoxSizer" name="sizer_1" base="EditBoxSizer">
<orient>wxVERTICAL</orient>
<object class="sizerslot" />
</object>
</object>
</application>
""" % {"name": hmi_name, "class": "Class_%s" % hmi_name})
if wx.Platform == '__WXMSW__':
wxg_filename = "\"%s\"" % wxg_filename
self.launch_wxglade([wxg_filename])