"""
parse simple structures from an xml tree
We only support a subset of features but should be enough
for custom structures
"""
import os
import importlib
from lxml import objectify
from opcua.ua.ua_binary import Primitives
def get_default_value(uatype):
if uatype == "String":
return "None"
elif uatype == "Guid":
return "uuid.uuid4()"
elif uatype in ("ByteString", "CharArray", "Char"):
return None
elif uatype == "Boolean":
return "True"
elif uatype == "DateTime":
return "datetime.utcnow()"
elif uatype in ("Int8", "Int16", "Int32", "Int64", "UInt8", "UInt16", "UInt32", "UInt64", "Double", "Float", "Byte", "SByte"):
return 0
else:
return "ua." + uatype + "()"
class Struct(object):
def __init__(self, name):
self.name = name
self.fields = []
self.code = ""
def get_code(self):
if not self.fields:
return """
class {}(object):
pass
""".format(self.name)
self._make_constructor()
self._make_from_binary()
self._make_to_binary()
return self.code
def _make_constructor(self):
self.code = """
class {0}(object):
'''
{0} structure autogenerated from xml
'''
def __init__(self, data=None):
if data is not None:
self._binary_init(data)
return
""".format(self.name)
for field in self.fields:
self.code += " self.{} = {}\n".format(field.name, field.value)
def _make_from_binary(self):
self.code += '''
@staticmethod
def from_binary(data):
return {}(data=data)
def _binary_init(self, data):
'''.format(self.name)
for field in self.fields:
if hasattr(Primitives, field.uatype):
if field.array:
self.code += ' self.{} = ua.ua_binary.Primitives.{}.unpack_array(data)\n'.format(field.name, field.uatype)
else:
self.code += ' self.{} = ua.ua_binary.Primitives.{}.unpack(data)\n'.format(field.name, field.uatype)
else:
if field.array:
self.code += '''
length = ua.ua_binary.Primitives.Int32.unpack(data)
if length == -1:
self.{0} = None
else:
self.{0} = [ua.{1}.from_binary(data) for _ in range(length)]
'''.format(field.name, field.uatype)
else:
self.code += " self.{} = ua.{}.from_binary(data)\n".format(field.name, field.uatype)
def _make_to_binary(self):
self.code += '''
def to_binary(self):
packet = []
'''
for field in self.fields:
if hasattr(Primitives, field.uatype):
if field.array:
self.code += ' packet.append(ua.ua_binary.Primitives.{}.pack_array(self.{}))\n'.format(field.uatype, field.name)
else:
self.code += ' packet.append(ua.ua_binary.Primitives.{}.pack(self.{}))\n'.format(field.uatype, field.name)
else:
if field.array:
self.code += '''
if self.{0} is None:
packet.append(ua.ua_binary.Primitives.Int32.pack(-1))
else:
packet.append(ua.ua_binary.Primitives.Int32.pack(len(self.{0})))
for element in self.{0}:
packet.append(element.to_binary())
'''.format(field.name)
else:
self.code += " packet.append(self.{}.to_binary())\n".format(field.name)
self.code += ' return b"".join(packet)'
class Field(object):
def __init__(self, name):
self.name = name
self.uatype = None
self.value = None
self.array = False
class StructGenerator(object):
def __init__(self):
self.model = []
def make_model_from_string(self, xml):
obj = objectify.fromstring(xml)
self._make_model(obj)
def make_model_from_file(self, path):
obj = objectify.parse(path)
root = obj.getroot()
self._make_model(root)
def _make_model(self, root):
for child in root.iter("{*}StructuredType"):
struct = Struct(child.get("Name"))
array = False
for xmlfield in child.iter("{*}Field"):
name = xmlfield.get("Name")
if name.startswith("NoOf"):
array = True
continue
field = Field(name)
field.uatype = xmlfield.get("TypeName")
if ":" in field.uatype:
field.uatype = field.uatype.split(":")[1]
field.value = get_default_value(field.uatype)
if array:
field.array = True
field.value = []
array = False
struct.fields.append(field)
self.model.append(struct)
def save_to_file(self, path):
_file = open(path, "wt")
self._make_header(_file)
for struct in self.model:
_file.write(struct.get_code())
_file.close()
def save_and_import(self, path, append_to=None):
"""
save the new structures to a python file which be used later
import the result and return resulting classes in a dict
if append_to is a dict, the classes are added to the dict
"""
self.save_to_file(path)
name = os.path.basename(path)
name = os.path.splitext(name)[0]
mymodule = importlib.import_module(name)
if append_to is None:
result = {}
else:
result = append_to
for struct in self.model:
result[struct.name] = getattr(mymodule, struct.name)
return result
def get_structures(self):
ld = {}
for struct in self.model:
exec(struct.get_code(), ld)
return ld
def _make_header(self, _file):
_file.write("""
'''
THIS FILE IS AUTOGENERATED, DO NOT EDIT!!!
'''
from datetime import datetime
import uuid
from opcua import ua
""")
if __name__ == "__main__":
import sys
from IPython import embed
sys.path.insert(0, ".") # necessary for import in current dir
#xmlpath = "schemas/Opc.Ua.Types.bsd"
xmlpath = "schemas/example.bsd"
c = StructGenerator(xmlpath, "structures.py")
c.run()
import structures as s
#sts = c.get_structures()
embed()
