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HowTo: Enhancing Windows Vista Search With iFilters

Thursday, 13 December 2007

Windows Vista Search (and Windows desktop Search) uses plug-ins called iFilters to allow the search engine to index the contents of different files types. While Windows Vista Search supports numerous document types that you would expect, such as .TXT and .HTML, there are numerous document types that are used on a day to day basis, .PDF for example, that are not supported. By adding an iFilter, you can increase the effectiveness of Windows Vista Search by extending the range of files that can have their content indexed.

Windows Vista Search

Windows Vista Search (and Windows desktop Search), using the built-in iFilters, supports the following document types by default:

Default iFilter Types
iFilter Name	Document Type
nlhtml.dll	ASCX, ASP, ASPX, CSS, HHC, HTA, HTM, HTML, HHT, HTW, HTX, ODC, STM
offfilt.dll	DOC, DOT, POT, PPS, PPT, XLB, XLC, XLS, XLT
query.dll	TXT, ASM, BAT, C, CPP, CXX, CMD, DEF, DIC, H, HPP, XML(plain text)
rtffilt.dll	RTF
mimefilt.dll	EML

While this is fine for these file types, I happen to have a large library of IT reference books stored as other document types, such as .PDF and .CHM. As Windows Vista search does not index the contents of these files it is a manual effort to open each file and continue the search within the file itself. A slight problem if you have more than a couple of hundred documents (or reference books, yes I should get out more). So luckily for people who work with document and file types that are not covered by the default iFilters, you can add additional filters.

Installing an Additional iFilter to Windows Vista Search

Couldn't be easier, simply download the iFilter setup file (assuming you have not written your own) for the document type or file type that you want to search indexing and run the installation. The majority of the links to iFilters in this document are well written pieces of code that come with their own install routines. The filter becomes active as soon as it is installed, this will initiate a rebuild index command to the search engine so your machine may churn for a little while while the search index is rebuild with the new data. To check that the new iFilter has been installed and configured as you want it, navigate to Control Panel>Indexing Options>Advanced>File Types and browse to the document type for the iFilter you have installed (in this case it is the CHM iFilter from Citeknet.com).

iFilter Downloads

iFilters for file types that are related to archival, for instance ZIP, CAB and RAR, will only facilitate indexing the files within the archive, the contents of the individual files are not indexed. As you can see, the iFilter has been installed and is not indexing this document type on both document properties and document contents (indexing properties only is the default).