beremiz

Dirty fix for error '_object_has_no_attribute_'getSlave' in EtherCAT extension

2018-08-10, Andrey Skvortsov
a3ac46366b86
Dirty 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


this is looks like dirty hack to fix strange problem with initial[0]
changing its type after returning from _init_ method to lxml.etree._Element
As a result all methods generated by class factory are lost.

For example, in function initMethod initial[0].__class__ points to
xmlclass.xmlclass.Config. After map(self.append, initial)
self.Config.__class__ is 'xmlclass.xmlclass.Config' as well.
But after returning from initMethod (_init) in CreateElement
self.Config.__class__ has changed to lxml.etree._Element.


I've noticed similar behavior if copy/deepcopy is used for any child
of etree.ElementBase. See simple example below.
[-------------------------------------------------------------]
#!/usr/bin/python

from __future__ import print_function
from lxml import etree
import copy

class DefaultElementClass(etree.ElementBase):
def getLocalTag(self):
return etree.QName(self.tag).localname


def printInformation(x):
print(x, x.__class__, "getLocalTag" in dir(x))


a = DefaultElementClass()
printInformation(a)

#
printInformation(copy.copy(a))
printInformation(copy.deepcopy(a))
[-------------------------------------------------------------]
#!/usr/bin/env python
# -*- coding: utf-8 -*-
# This file is part of Beremiz.
# See COPYING file for copyrights details.
from __future__ import absolute_import
import os
from lxml import etree
import util.paths as paths
from plcopen.structures import StdBlckLibs
ScriptDirectory = paths.AbsDir(__file__)
class XSLTModelQuery(object):
""" a class to handle XSLT queries on project and libs """
def __init__(self, controller, xsltpath, ext=None):
# arbitrary set debug to false, updated later
self.debug = False
# merge xslt extensions for library access to query specific ones
xsltext = [
("GetProject", lambda *_ignored:
[controller.GetProject(self.debug)]),
("GetStdLibs", lambda *_ignored:
[lib for lib in StdBlckLibs.values()]),
("GetExtensions", lambda *_ignored:
[ctn["types"] for ctn in controller.ConfNodeTypes])
]
if ext is not None:
xsltext.extend(ext)
# parse and compile. "beremiz" arbitrary namespace for extensions
self.xslt = etree.XSLT(
etree.parse(
os.path.join(ScriptDirectory, xsltpath),
etree.XMLParser()),
extensions={("beremiz", name): call for name, call in xsltext})
def _process_xslt(self, root, debug, **kwargs):
self.debug = debug
res = self.xslt(root, **{k: etree.XSLT.strparam(v) for k, v in kwargs.iteritems()})
# print(self.xslt.error_log)
return res
# -------------------------------------------------------------------------------
# Helpers functions for translating list of arguments
# from xslt to valid arguments
# -------------------------------------------------------------------------------
def _StringValue(x):
return x
def _BoolValue(x):
return x in ["true", "0"]
def _translate_args(translations, args):
return [translate(arg[0]) if len(arg) > 0 else None
for translate, arg in
zip(translations, args)]