[This is preliminary documentation and subject to change.]
The IFilter interface does not require any particular property to be exposed, but Index Server takes advantage of the existence of some properties. Filter writers are encouraged to expose the following properties. Exposing the same properties from multiple object formats allows the client of Index Server to make a common query across many (or all) types of object.
The properties below are named by the format identifier of the property set, followed by either a number corresponding to the PROPID of the PROPSPEC for properties of type PRSPEC_PROPID or a string corresponding to the string name for properties of type PRSPEC_LPWSTR.