Listening for Changes

The Volue Insight Timeseries API supports listening for changes to curves. An event listener behaves like an infinite iterator, returning change events as they happen.

Setting up a listener

Find a list of curves (or curve IDs) and pass them to session.events(). Two optional arguments are available:

• start_time — resume a listener without receiving old events
• timeout — stop waiting after the specified number of seconds

When a curve is updated, the iterator yields a CurveEvent object. If timeout is specified and expires, an EventTimeout object is returned.

>>> curves = session.search(category='WND', area=['EE', 'LT'], frequency='H')
>>> events = session.events(curves, timeout=5)
>>> for e in events:
...     print(e)

See the listening for changes example for a complete script that appends new data to a CSV file on each event.