for testing and deploying your application
for finding and fixing issues
for empowering human code reviews
"""
JSON encoder / decoder for OPC UA objects
Not yet used anywhere, but could be useful in the future for sending data to
external system such as a web based app
from json import JSONEncoder, JSONDecoder
from opcua import ua
from datetime import datetime
# FIXME this JSON utility is not finished, should implement encoding / decoding of useful UA types
class UaJSONEncoder(JSONEncoder):
JSON encoder utility which is extended to handle opc ua objects
def default(self, o):
if isinstance(o, datetime):
return {
'__type__': 'datetime',
'year': o.year,
'month': o.month,
'day': o.day,
'hour': o.hour,
'minute': o.minute,
'second': o.second,
'microsecond': o.microsecond
}
elif isinstance(o, ua.NodeId):
'__type__': 'NodeId',
'Identifier': o.Identifier,
'NamespaceIndex': o.NamespaceIndex,
else:
return JSONEncoder.default(self, o)
class UaJSONDecoder(JSONDecoder):
JSON decoder utility which is extended to handle opc ua objects
def __init__(self):
JSONDecoder.__init__(self, object_hook=self.dict_to_object)
def dict_to_object(self, d):
if '__type__' not in d:
return d
type = d.pop('__type__')
if type == 'datetime':
return datetime(**d)
elif type == 'NodeId':
return ua.NodeId(**d)
# decoder subclass can't handle this object type; put it back in the dict so super throws TypeError
d['__type__'] = type
FreeOpcUa /
python-opcua
