Not all file types are crawled by SharePoint out of
the box. Therefore, it is important to identify the file types that are
important to the organization and make sure they are both crawled and
searchable. It is probably not possible or desirable to crawl all file
types found in an organization (especially those lingering on file
shares); however, some thought should be given to which file types hold
content relevant to the business's needs.
1. Adding a File Type to the Content Index
The first measure to take after
identifying a potentially unsupported file type is to add it to the
content index. This is done in the Central Administration under the
Search service application. On the left menu is displayed the File Types
menu item under the Crawling section (see Figure 1).
The File Types page holds a list of all recognized file types for the SharePoint crawler (Figure 2).
The most common files found in a SharePoint environment and all
Microsoft Office file types are represented here. However, many file
types common to most organizations, such as Portable Document Format
(PDF) and Rich Text Format (RTF), are not added out of the box. Many
other file types may also be found in organizations. Many are unique and
complicated file formats. Others are just different names for plain
text files. It would be a major undertaking for Microsoft to support
even a fraction of them. Instead Microsoft has created a mechanism for
adding new file types and converting them into something SharePoint's
crawler can recognize.
To add a new file type, click
the New File Type link at the top of the page. A new file type may
already be a supported format, but the file extension might not be
recognized by SharePoint. For example, there can be many variations of
file name extensions for flat text files (e.g., .log). See Figure 3.
Additionally, some file types will not appear by default but can be
recognized and decoded by the default iFilters. If it is necessary to
crawl these files, adding them is a simple but required task.
Some files will require the
addition of an iFilter. An iFilter is a component that can decode a
specific file type and allow the crawler to understand and store the
text and metadata from it in its databases and index. Although many
iFilters are provided for free from Microsoft and other sources, not all
are installed by default by SharePoint 2010. Finding and installing
these iFilters can be necessary to index certain file types. One of the
most common file types found that is not supported by default in
SharePoint is the Rich Text Format (RTF); another is the Portable
Document Format (PDF).
To add the PDF format, it is
recommended that you acquire an installable iFilter from Adobe or
another third-party vendor. Other third-party vendors offer iFilters
that have a larger range of compatibility with different PDF generation
types and perform significantly better than Adobe's but come with a
relatively modest price tag. Depending on what type of PDF file
generator an organization uses and how many PDF documents it has, it may
opt to use a third-party paid-for iFilter.
1.1. Installing Adobe's iFilter
Acrobat iFilter can be
acquired from Adobe's web site. It will be necessary to download and
install the 64-bit version available from www.adobe.com/support/downloads/detail.jsp?ftpID=4025.The
installation requires some additional installation steps. These steps
are outlined in the PDF guide available on the download link on Adobe's
site www.adobe.com/special/acrobat/configuring_pdf_ifilter_for_ms_sharepoint_2007.pdf).
The guide is targeted for Microsoft Office SharePoint Server 2007, but
the same instructions apply except for the location of the registry key.
The basics of installing the 64-bit iFilter are as follows:
Open the registry (Regedit.exe) and add the .pdf file extension value to the filter extension container (Figure 4) at \\HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Office Server\14.0\Search\Setup\ContentIndexCommon\Filters\Extension. The default value that should be applied is {E8978DA6-047F-4E3D-9C78-CDBE46041603}.
Add an icon to the iFilter install (see "Adding Icons to File Types").
Restart the Search service application by running Services.msc at the run dialog, finding the SharePoint Server Search 14 service, and restarting it.
Perform a full crawl.
Other iFilter vendors'
installation programs perform these tasks automatically. However, it is
always necessary to perform a full crawl to retrieve new file types.
Please follow the iFilter vendor's instructions when adding a new
iFilter.
Before PDF documents or any
new file type can be crawled, the Search service application will need
to be restarted. The easiest way to do this is to go to the Services
snap-in by typing "services.msc" in the search box in the Start menu on
the server, find the SharePoint Server Search 14 service, and restart it
(see Figure 5).
After the service is restarted, it will be necessary to launch a full
crawl to pick up any PDF files. For this reason, it is wise to install
the PDF iFilter before starting the crawler on a large document set for
the first time.
NOTE
The Search service application can also be restarted using the NET START and NET STOP commands from a command prompt. The name of the Search service application is OSearch14.
1.2. Indexing Rich Text Format Files
Adding the Rich Text Format
(RTF) file type requires finding the RTF iFilter on the server or on
Microsoft's web site and installing and registering it on the SharePoint
index server. Additionally, adding the RTF file type is necessary.
Check if the RTF iFilter is on the server. It is called rtffilt.dll and is in the %windir%\system32 folder (probably C:\Windows\System32). If it isn't there, the self-extracting RTF iFilter file rtf.exe can be downloaded from Microsoft's web site (http://support.microsoft.com/kb/291676/en-us).
Register the iFilter with the regsvr32 command at a command prompt by placing this line in the run dialog: regsvr32 rtffilt.dll.
Add the RTF file type to the File Types page in Central Administration, as shown in Figure 6.
Run Services.msc at the run dialog, find the SharePoint Server Search 14 service, and restart it.
Start a full crawl.
1.3. Adding or Changing the File Type Icon
New file types will usually not
have an icon associated with them. SharePoint Search will display a
default blank icon in such cases after the file type has been added.
Even if there is a definition already there, many organizations will
want to adjust the icons to match their own style requirements.
To add a new file type icon or change the existing one, first the new icon must be copied to the C:\Program Files\Common Files\Microsoft Shared\Web Server Extensions\14\TEMPLATE\IMAGES\
directory. Images can be downloaded or created. They should be icon
size, roughly 16 pixels by 16 pixels. For PDF files, Adobe offers a free
17-pixel-by-17-pixel icon, with some legal restrictions, at www.adobe.com/misc/linking.html#pdficon. This will also work, but larger icons may cause formatting problems.
After the icon is added to the IMAGES directory, the DOCICON.xml file in the C:\Program Files\Common Files\Microsoft Shared\Web Server Extensions\14\TEMPLATE\XML
directory needs to have a key added to tell SharePoint the name of the
new file type's icon. For the PDF icon, the line should read <Mapping Key="pdf" Value="pdficon.gif"/>, where pdficon.gif is the name of the icon you saved to the directory.
NOTE
Since a full crawl will
be needed to include new file types, it is advisable to add any iFilters
and file types before a full crawl in a large production environment.
