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))
[-------------------------------------------------------------]
from __future__ import absolute_import
import sys
import gluon.contrib.simplejson as simplejson
class JSONRPCServiceBase(object):
def __init__(self):
self.methods = {}
def response(self, id, result):
return simplejson.dumps({'version': '1.1', 'id': id,
'result': result, 'error': None})
def error(self, id, code, message):
return simplejson.dumps({
'id': id,
'version': '1.1',
'error': {'name': 'JSONRPCError',
'code': code,
'message': message}
})
def add_method(self, name, method):
self.methods[name] = method
def process(self, data):
data = simplejson.loads(data)
id, method, params = data["id"], data["method"], data["params"]
if method in self.methods:
try:
result = self.methods[method](*params)
return self.response(id, result)
except Exception:
etype, eval, _etb = sys.exc_info()
return self.error(id, 100, 'Exception %s: %s' % (etype, eval))
except BaseException:
etype, eval, _etb = sys.exc_info()
return self.error(id, 100, '%s: %s' % (etype.__name__, eval))
else:
return self.error(id, 100, 'method "%s" does not exist' % method)
def listmethods(self):
return self.methods.keys()