ISAPI filter
<World-Wide Web> A replaceable
DLL which the
server calls whenever there is an
HTTP request.
When the filter is first loaded, it communicates to the server what sort of notifications will be accepted.
After that, whenever a selected event occurs, the filter is called to process the event.
Example applications of ISAPI filters include custom
authentication schemes,
compression,
encryption, logging, traffic analysis or other request analyses.