reading data which does not conform to stream filter

Question

Hi guys,

I have another question about stream filters:

e.g.

1) write item with data format XY to stream

2) enable new stream filter which will now reject new items with format XY

3) write another item with format XY --> will be rejected by stream filter

4) liststreamkeyitems --> returns also data with format XY

regarding 4) why is this the case? I thought that data with format rejected by a stream filter is not returned when reading?

So is a stream filter not applied when reading but only when writing to validate items?

Can you please clarify that?

Thanks!

Answer 1

A stream filter is applied when both writing and reading.

But - a stream filter activated on a stream does not apply retroactively to items already published on the stream. It only applies for future items after the point it is acticated. This fits in with the blockchain idea of immutability.

Of course, there is always still the option of validating at the application level.