plcopen/InstancesPathCollector.py
author Andrey Skvortsov <andrej.skvortzov@gmail.com>
Fri, 24 Aug 2018 13:41:43 +0300
changeset 2297 96ca6b056c55
parent 1953 5736d25bb393
child 3750 f62625418bff
permissions -rw-r--r--
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():
<type 'exceptions.AttributeError'>:_'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
1942
a4382ae1ba82 Added /plcopen/InstancesPathCollector.py, to move more model xslt querying code away from PLCController.py.
Edouard Tisserant <edouard.tisserant@gmail.com>
parents:
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#!/usr/bin/env python
a4382ae1ba82 Added /plcopen/InstancesPathCollector.py, to move more model xslt querying code away from PLCController.py.
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parents:
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# -*- coding: utf-8 -*-
a4382ae1ba82 Added /plcopen/InstancesPathCollector.py, to move more model xslt querying code away from PLCController.py.
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# This file is part of Beremiz.
a4382ae1ba82 Added /plcopen/InstancesPathCollector.py, to move more model xslt querying code away from PLCController.py.
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parents:
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# See COPYING file for copyrights details.
a4382ae1ba82 Added /plcopen/InstancesPathCollector.py, to move more model xslt querying code away from PLCController.py.
Edouard Tisserant <edouard.tisserant@gmail.com>
parents:
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a4382ae1ba82 Added /plcopen/InstancesPathCollector.py, to move more model xslt querying code away from PLCController.py.
Edouard Tisserant <edouard.tisserant@gmail.com>
parents:
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from __future__ import absolute_import
a4382ae1ba82 Added /plcopen/InstancesPathCollector.py, to move more model xslt querying code away from PLCController.py.
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parents:
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from plcopen.XSLTModelQuery import XSLTModelQuery
a4382ae1ba82 Added /plcopen/InstancesPathCollector.py, to move more model xslt querying code away from PLCController.py.
Edouard Tisserant <edouard.tisserant@gmail.com>
parents:
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1953
5736d25bb393 PEP8 and PyLint conformance: whitespaces and stuff
Edouard Tisserant
parents: 1942
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1942
a4382ae1ba82 Added /plcopen/InstancesPathCollector.py, to move more model xslt querying code away from PLCController.py.
Edouard Tisserant <edouard.tisserant@gmail.com>
parents:
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class InstancesPathCollector(XSLTModelQuery):
a4382ae1ba82 Added /plcopen/InstancesPathCollector.py, to move more model xslt querying code away from PLCController.py.
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parents:
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    """ object for collecting instances path list"""
a4382ae1ba82 Added /plcopen/InstancesPathCollector.py, to move more model xslt querying code away from PLCController.py.
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parents:
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    def __init__(self, controller):
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        self.Instances = []
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        XSLTModelQuery.__init__(self,
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                                controller,
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                                "instances_path.xslt",
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                                [("AddInstance", self.AddInstance)])
a4382ae1ba82 Added /plcopen/InstancesPathCollector.py, to move more model xslt querying code away from PLCController.py.
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parents:
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a4382ae1ba82 Added /plcopen/InstancesPathCollector.py, to move more model xslt querying code away from PLCController.py.
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    def AddInstance(self, context, *args):
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        self.Instances.append(args[0][0])
a4382ae1ba82 Added /plcopen/InstancesPathCollector.py, to move more model xslt querying code away from PLCController.py.
Edouard Tisserant <edouard.tisserant@gmail.com>
parents:
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a4382ae1ba82 Added /plcopen/InstancesPathCollector.py, to move more model xslt querying code away from PLCController.py.
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parents:
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    def Collect(self, root, name, debug):
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        self._process_xslt(root, debug, instance_type=name)
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a4382ae1ba82 Added /plcopen/InstancesPathCollector.py, to move more model xslt querying code away from PLCController.py.
Edouard Tisserant <edouard.tisserant@gmail.com>
parents:
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        res = self.Instances
a4382ae1ba82 Added /plcopen/InstancesPathCollector.py, to move more model xslt querying code away from PLCController.py.
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parents:
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        self.Instances = []
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        return res