How to use dtSearch with IFilters

Last Reviewed: August 6, 2013

Article: DTS0205

Applies to: dtSearch 7.22 and later

dtSearch includes its own file parsers for a wide range file formats, which are listed here: What file formats does dtSearch support?

IFilters provide a way to add file format support for additional formats.  IFilters are components that enable Microsoft search products to extract text from documents. For example, when you install Microsoft OneNote, an IFilter is installed to enable searching of *.one files.  

dtSearch Desktop

To tell dtSearch to use installed IFilters to process some of your files, set up a rule in Options > Preferences > File Types:

1.  In dtSearch Desktop, click Options > Preferences > File Types

2.  Under File type select IFilter

3.  Under Filename filters to identify files of this type enter one or more filename filters (like *.dwg) to identify files that should be indexed using IFilters.

dtSearch Engine API

To use IFilters in an application that uses the dtSearch Engine, first create one or more file type rules in dtSearch Desktop as described above.   These rules are stored in a filetype.xml file that will be in your dtSearch UserData folder.

Next, in your application use Options.FileTypeTableFile to specify the location of the filetype.xml file to use in your application.  

Finally, make sure dtSearch Engine is loading the dtv_ifilter.dll component so IFilter integration is enabled.  The dtv_ifilter.dll component is an external file parser and must be located in a "Viewers" subfolder under the dtSearch "Home" directory.  For more information on the Home directory, see the "Home and Private Directories" in the dtSearch Text Retrieval Engine Programmer's Reference.

Additional Information

dtSearch implements IFilter support using an external file parser DLL, dtv_ifilter.dll.  If this component is not installed, IFilter integration will not work.  For more information on IFilters, see http://en.wikipedia.org/wiki/IFilter