beremiz

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

2018-08-10, Andrey Skvortsov
a3ac46366b86
file isExecutable
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 runtime.
#
# Copyright (C) 2007: Edouard TISSERANT and Laurent BESSARD
#
# See COPYING.Runtime file for copyrights details.
#
# This library is free software; you can redistribute it and/or
# modify it under the terms of the GNU Lesser General Public
# License as published by the Free Software Foundation; either
# version 2.1 of the License, or (at your option) any later version.
# This library 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
# Lesser General Public License for more details.
# You should have received a copy of the GNU Lesser General Public
# License along with this library; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
from __future__ import absolute_import
from __future__ import print_function
import socket
import threading
import zeroconf
service_type = '_PYRO._tcp.local.'
class ServicePublisher(object):
def __init__(self):
# type: fully qualified service type name
self.serviceproperties = {'description': 'Beremiz remote PLC'}
self.name = None
self.ip_32b = None
self.port = None
self.server = None
self.service_name = None
self.retrytimer = None
def RegisterService(self, name, ip, port):
try:
self._RegisterService(name, ip, port)
except Exception:
self.retrytimer = threading.Timer(2, self.RegisterService, [name, ip, port])
self.retrytimer.start()
def _RegisterService(self, name, ip, port):
# name: fully qualified service name
self.service_name = 'Beremiz_%s.%s' % (name, service_type)
self.name = name
self.port = port
self.server = zeroconf.Zeroconf()
print("MDNS brodcasting on :" + ip)
if ip == "0.0.0.0":
ip = self.gethostaddr()
print("MDNS brodcasted service address :" + ip)
self.ip_32b = socket.inet_aton(ip)
self.server.register_service(
zeroconf.ServiceInfo(service_type,
self.service_name,
self.ip_32b,
self.port,
properties=self.serviceproperties))
self.retrytimer = None
def UnRegisterService(self):
if self.retrytimer is not None:
self.retrytimer.cancel()
if self.server is not None:
self.server.unregister_service(
zeroconf.ServiceInfo(service_type,
self.service_name,
self.ip_32b,
self.port,
properties=self.serviceproperties))
self.server.close()
self.server = None
def gethostaddr(self, dst='224.0.1.41'):
s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
try:
s.connect((dst, 7))
(host, _port) = s.getsockname()
s.close()
if host != '0.0.0.0':
return host
except Exception:
pass
return socket.gethostbyname(socket.gethostname())