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More about Searching Indexing Services With ASP

A previous article demonstrated how ASP could be used to create a web front-end to the Windows Indexing Service. While the search results page demonstrated in the article contained most of what is needed to create a results page, its formatting of the search results was pretty basic, as can be seen below:

Output from SearchResults.asp

Contrast this with the search results page from this website (shown below). This demonstrates what sort of formatting can be applied to the search results. If you want to see this page in action, try the search facility on this website.

Output from an improved SearchResults.asp - as taken from my personal website

Improving the display of column properties

As was described in the previous article, each search result contains a number of column properties. These contain information about each search result. In the previous article, the properties used were: FileName, doctitle, Size, Create and Characterization. As will be described below, each of these can be used to provide useful information in search results pages.

Hyperlinking the search result's filename

The FileName column property contains the search result's filename (e.g. default.htm). However, a more useful column property is vpath, which also contains the file's path as well as its filename (e.g. /financial/reports/june2002/default.htm). Once the file's path is know, it is straightforward to hyperlink the search result's URL using something like the following:

Const SERVER_URL = "http://www.brettb.com"
Response.write "<b>URL:</b> <a href=""" & SERVER_URL & oRS("vpath") & """>" & SERVER_URL & oRS("vpath") & "</a><br>"

A common convention when presenting search results is to hyperlink the document's name to its URL. Indexing Service uses the doctitle column property to store the document's name):

Const SERVER_URL = "http://www.brettb.com"
Response.write "<b>URL:</b> <a href=""" & SERVER_URL & oRS("vpath") & """>" & oRS("doctitle") & "</a><br>"

Displaying the search result's file size

The Size column property contains the size of the file in bytes. A small formula can be used to display the file's size in Kilobytes, which is often a better unit of measure for file sizes:

Response.write "<b>Size:</b> " & Round(CInt(oRS("Size"))/1024, 1) & "K <br>"

Displaying the document creation and modification dates

The creation and modification date and time for files are contained within the Create and Write column properties, respectively. These can be formatted to display a more user friendly date by use of the FormatDateTime VBScript function as shown below:

Response.write "<b>Create:</b> " & FormatDateTime(oRS("Create"), 1) & "<br>"
Response.write "<b>Write:</b> " & FormatDateTime(oRS("Write"), 1) & "<br>"

Further document properties

A number of other document properties may be of interest, such as HitCount (the number of words matching the query that were found in the file), and Rank (how closely the file matched the query). A more detailed description of the Rank column property is in the following section.

A complete listing of column properties is available in the IIS documentation. Many properties are only of relevence if Microsoft Office documents are being indexed. Remember that if you wish to use any additional columns then they must be listed in the Columns property of the Indexing Service Query COM component, e.g.

oQuery.Columns = "DocAuthor, vpath, doctitle, FileName, Path, Write, Size, Rank, Create, Characterization, HitCount"

Displaying a file's rank

The Rank column property is used as a measure of how closely a document returned by Indexing Service matched the search query. Rank ranges between 0 and 1000, with 1000 being the closest match. The calculation of rank is fairly complex, but to summarise, rank depends on the number of times the query terms appear in the document, as well as the number of times the query terms appear in the Indexing Service catalog.

In the search catalog on my own personal site, searches for "ASP" will return results with a low rank, because that word appears frequently (since I am an ASP developer and have lots of pages about ASP). By contrast, searches for "tomato" will return a high rank for the page about my biotechnology career, since it is the only page to contain numerous references to tomatoes.

In a search results page, rank can be displayed as a percentage by simply dividing the Rank by 10:

Response.write "<b>Rank:</b> " & CInt(oRS("Rank")/10) & "%<br>"

Alternatively, it can be displayed graphically. There are a number of ways of achieving this. On my personal search page, the results are accompanied by a graphic showing from 0 to 10 filled bars, according to the rank. So a document matching with a ranking of between 700 and 800 will get 8 bars, and therefore an 80% ranking. Obviously the number of filled bars can only give an approximate ranking, but it is there as a visual aid so an accurate ranking is not important.

If you want to use the method I use, the code is below. The code should of course be executed for each page in the search results.

iCurrentRanking = oRS("Rank") 'Retrieve the search ranking for this particular search result

If iCurrentRanking > 900 Then
    iRanking = 10
ElseIf iCurrentRanking > 800 Then
    iRanking = 9
ElseIf iCurrentRanking > 700 Then
    iRanking = 8
ElseIf iCurrentRanking > 600 Then
    iRanking = 7
ElseIf iCurrentRanking > 500 Then
    iRanking = 6
ElseIf iCurrentRanking > 400 Then
    iRanking = 5
ElseIf iCurrentRanking > 300 Then
    iRanking = 4
ElseIf iCurrentRanking > 200 Then
    iRanking = 3
ElseIf iCurrentRanking > 100 Then
    iRanking = 2
Else
    iRanking = 1
End If

sCurrentRankingAltTag = (iRanking * 10) & " percent match"
'Create an ALT tag for the ranking image

The appropriate rank image is then inserted using the following ASP:

<img src="images/<%=iRanking%>bars.png" alt="<%=sCurrentRankingAltTag%>" width="80" height="17">

Note that the images are in the images sub-folder, and are named from 1bars.png to 10bars.png. Examples are shown below:

1bars.png, representing 10% match
1bars.png

4bars.png, representing 40% match
4bars.png

8bars.png, representing 80% match
8bars.png

10bars.png, representing 100% match
10bars.png

Code samples and working ASP pages

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