Indexing Service for Microsoft® Windows® 2000 and later uses filters to extract content and properties of files for inclusion in a searchable index. Microsoft provides file-format specific filters for several types of files, including Microsoft Office documents and HTML files.

This section describes the use of the IFilter interface to produce custom filters for other specific file formats. It contains the following sections:

• About Filters describes how the Indexing Service filter extracts text and properties from a file.
• Applying Filters describes how the Indexing Service filtering process determines which filters to use for particular files.
• Constructing Filters describes the construction of several sample filters.
• Testing Filters describes how to use the IFilter Test Suite to test filters.
• Filter Samples presents details about the sample filters in the Platform Software Development Kit (SDK).

For an overview of how the IFilter interface regards documents and their properties, see Properties of Documents. In particular, for a synopsis and example of how the IFilter interface processes a document, see Property Filtering.