def write(self, value: bytes, request: AmsPacket = None):
"""Update the variable value, respecting notifications"""
if self.value != value:
if self.notifications:
header = structs.SAdsNotificationHeader()
header.hNotification = 0
header.nTimeStamp = dt_to_filetime(datetime.now())
header.cbSampleSize = len(value)
# Perform byte-write into the header
dst = ctypes.addressof(
header) + structs.SAdsNotificationHeader.data.offset
ctypes.memmove(dst, value, len(value))
for notification_handle in self.notifications:
# It's hard to guess the exact AmsAddr from here, so instead
# ignore the address and search for the note_handle
for key, func in callback_store.items():
# callback_store is keyed by (AmsAddr, int)
if key[1] != notification_handle:
continue
header.hNotification = notification_handle
addr = key[0]
# Call c-wrapper for user callback
func(addr.amsAddrStruct(), header, 0)
self.value = value
def test_notification_decorator_filetime(self):
# type: () -> None
"""Test passthrough of FILETIME value by notification decorator"""
@self.plc.notification(timestamp_as_filetime=True)
def callback(handle, name, timestamp, value):
self.assertEqual(timestamp, 132223104000000000)
notification = structs.SAdsNotificationHeader()
notification.nTimeStamp = 132223104000000000
notification.cbSampleSize = 1
notification.data = 5
callback(pointer(notification), "TestName")
def create_notification_struct(self, payload):
# type: (bytes) -> structs.SAdsNotificationHeader
buf = b"\x00" * 12 # hNotification, nTimeStamp
buf += struct.pack("<i", len(payload))
buf += payload
notification = structs.SAdsNotificationHeader()
resize(notification, len(buf))
memmove(
pointer(notification),
(ctypes.c_ubyte * len(buf)).from_buffer_copy(buf),
sizeof(notification),
)
return notification
def create_notification_struct(payload: bytes) -> \
structs.SAdsNotificationHeader:
"""Create notification callback structure"""
buf = b"\x00" * 12 # hNotification, nTimeStamp
buf += struct.pack("<i", len(payload))
buf += payload
notification = structs.SAdsNotificationHeader()
resize(notification, len(buf))
memmove(
pointer(notification),
(ctypes.c_ubyte * len(buf)).from_buffer_copy(buf),
sizeof(notification),
)
return notification
def test_notification_decorator(self):
# type: () -> None
"""Test decoding of header by notification decorator"""
@self.plc.notification()
def callback(handle, name, timestamp, value):
self.assertEqual(handle, 1234)
self.assertEqual(name, "TestName")
self.assertEqual(timestamp, datetime.datetime(2020, 1, 1))
self.assertEqual(value, bytearray((5, )))
notification = structs.SAdsNotificationHeader()
notification.hNotification = 1234
notification.nTimeStamp = 132223104000000000
notification.cbSampleSize = 1
notification.data = 5
callback(pointer(notification), "TestName")