def CreateFromRange(firstTime: datetime, lastTime: datetime):
"""
Creates a seek filter over a single date range (inclusive list).
Parameters
----------
firstTime: the first time if the query (inclusive).
lastTime: the last time of the query (inclusive).
"""
return timestampSeekFilter(Ticks.FromDateTime(firstTime),
Ticks.FromDateTime(lastTime))
def TryGetDateTime(self) -> tuple[datetime, bool]:
"""
Attempts to get the timestamp field of this key instance.
"""
if self.Timestamp > Limits.MAXTICKS:
return (Empty.DATETIME, False)
return (Ticks.ToDateTime(self.Timestamp), True)
def CreateFromRangeInterval(firstTime: datetime, lastTime: datetime,
interval: timedelta, tolerance: timedelta):
"""
Creates a seek filter over a single date range (inclusive list), skipping values
based on specified `timedelta` interval and tolerance.
Parameters
----------
firstTime: the first time if the query (inclusive).
lastTime: the last time of the query (inclusive).
interval: the exact interval for the scan. Example: 0.1 seconds.
tolerance: the width of every window. Example: 0.001 seconds.
"""
return timestampSeekFilter(Ticks.FromDateTime(firstTime),
Ticks.FromDateTime(lastTime),
Ticks.FromTimeDelta(interval),
Ticks.FromTimeDelta(interval),
Ticks.FromTimeDelta(tolerance))
def CreateFromRangeSubInterval(firstTime: datetime, lastTime: datetime,
mainInterval: timedelta,
subInterval: timedelta,
tolerance: timedelta):
"""
Creates a seek filter over a single date range (inclusive list), skipping values
based on specified `timedelta` main /sub intervals and tolerance.
Parameters
----------
firstTime: the first time if the query (inclusive).
lastTime: the last time of the query (inclusive).
mainInterval: the smallest interval that is exact. Example: 0.1 seconds.
subInterval: the interval that will be parsed (round possible). Example: 0.0333333 seconds.
tolerance: the width of every window. Example: 0.001 seconds.
"""
return timestampSeekFilter(Ticks.FromDateTime(firstTime),
Ticks.FromDateTime(lastTime),
Ticks.FromTimeDelta(mainInterval),
Ticks.FromTimeDelta(subInterval),
Ticks.FromTimeDelta(tolerance))
def writeTest():
# Create historian connection (the root API object)
historian = historianConnection("localhost")
instance: Optional[historianInstance] = None
try:
print("Connecting to openHistorian...")
historian.Connect()
if not historian.IsConnected or len(historian.InstanceNames) == 0:
print("No openHistorian instances detected!")
else:
# Get first historian instance
initialInstance = historian.InstanceNames[0]
print(f"Opening \"{initialInstance}\" database instance...")
instance = historian.OpenInstance(initialInstance)
key = historianKey()
key.PointID = 1
key.Timestamp = Ticks.FromDateTime(datetime.utcnow())
value = historianValue()
value.AsSingle = np.float32(1000.98)
value.AsQuality = QualityFlags.WARNINGHIGH
print("Writing test point...")
instance.Write(key, value)
except Exception as ex:
print(f"Failed to connect: {ex}")
finally:
if instance is not None:
instance.Dispose()
if historian.IsConnected:
print("Disconnecting from openHistorian")
historian.Disconnect()
def AsDateTime(self, value: datetime):
"""
Sets `Timestamp` type cast from a `datetime`
"""
self.Timestamp = Ticks.FromDateTime(value)
def Save(self, stream: binaryStream):
stream.WriteByte(0)
stream.WriteUInt64(Ticks.FromTimeDelta(self.timeout))
stream.WriteUInt64(self.maxReturnedCount)
stream.WriteUInt64(self.maxScanCount)
stream.WriteUInt64(self.maxSeekCount)
def TestWriteAndVerify(instance: historianInstance):
print("\r\nExecuting test write and read verification...\r\n")
utcTime = datetime.utcnow()
pointID = 1
pointTime = Ticks.FromDateTime(utcTime)
pointValue = np.float32(1000.98)
pointQuality = QualityFlags.WARNINGHIGH
key = historianKey()
value = historianValue()
key.PointID = pointID
key.Timestamp = pointTime
value.AsSingle = pointValue
value.AsQuality = pointQuality
print("Source values compared to those assigned to key/value pair:")
print(
f" Point ID Match = {key.PointID}, match: {pointID == key.PointID}"
)
print(
f" Point Time Match = {key.AsDateTime}, match: {pointTime == key.Timestamp}"
)
print(
f" Point Value Match = {value.AsSingle}, match: {pointValue == value.AsSingle}"
)
print(
f" Point Quality Match = {value.AsQuality}, match: {pointQuality == value.AsQuality}"
)
print("\r\nWriting a test point...")
instance.Write(key, value)
sleep(0.5) # Wait a moment before read
timeFilter = timestampSeekFilter.CreateFromRange(
utcTime - timedelta(milliseconds=1), utcTime)
pointFilter = pointIDMatchFilter.CreateFromList([pointID])
reader = instance.Read(timeFilter, pointFilter)
count = 0
print("\r\nReading test point...\r\n")
while reader.Read(key, value):
count += 1
print(
"Source values compared to those read from historian into key/value pair:"
)
print(
f" Point ID Match = {key.PointID}, match: {pointID == key.PointID}"
)
print(
f" Point Time Match = {key.AsDateTime}, match: {pointTime == key.Timestamp}"
)
print(
f" Point Value Match = {value.AsSingle}, match: {pointValue == value.AsSingle}"
)
print(
f" Point Quality Match = {value.AsQuality}, match: {pointQuality == value.AsQuality}"
)
print(f" Point Count Match = {count == 1}\r\n")