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Published: Saturday, December 04, 1999

Searching Through the Text of Each File on a WebSite, Part 3


In Part 2 we discussed the all but the recursive searching function for search.asp. At this point, we have read in the form field variables, and used the FileSystemObject to obtain the information for the folder we are interested in searching. All we have left is to write the function that will search through a particular folder and its subfolders, examining the contents of the files, looking for potential matches.

- continued -

This function has the following definition:

GetFiles(FolderObject, TermsArray, LastFileFound, SearchUsingAndBooleanLogic, FilesFoundCount)

The FolderObject is one of the objects encompassed by the FileSystemObject library (which was obtained using the GetFolder method). TermsArray is the array we created in Part 2. This array should contain 1 to many elements, each element of the array corresponding to one of the search terms entered by the user. LastFileFound is a string variable, representing the file name and path of the last listed file. SearchUsingAndBooleanLogic is a boolean variable that, if True, indicates that the user wants to search using AND between each term. If this variable is False, then the user wants to search using an OR between each term. Finally, FilesFoundCount is the number of matching files we've currently found.

Here is the exact function definition used in search.asp:

Function GetFiles(objFolder, aLookFor, strLF, bolLFFound,bolAnd, iCount)

Now, let's delve into this function! First off, there are two times when we want to exit the function immediately. First, if iCount is greater than the number of items we want to show per page, we need to exit the function. (Since this function may be called recursively, we need to have these checks at the beginning of our function.) Also, if the current folder being iterated begins with an underscore, we can assume it is a folder like _private or _vti_conf, and we don't want to iterate through those. The following lines of code should start off GetFiles:

'Exit function if current folder begins with an underscore If Left(objFolder.Name,1) = "_" then exit function 'If iCount > # of hits per page, exit function Const iListPerPage = 9 if iCount > iListPerPage then Exit Function

Now we need to iterate through each file in the folder object objFolder. We'll do so using a For Each ... Next loop. First, we'll need to define a number of variables, though:

Dim objFile, objTextStream, objFSO, strContents, iUBound, iLoop, bolValid Dim strTitle, iPos, strDesc iUBound = UBound(aLookFor) 'Iterate through each file in objFolder For Each objFile in objFolder.Files '... continued in next code example ...

We don't want to search every file, only those files that have the .SHTML extension. For your site, you may only want to search .ASP files, or .ASP files and .HTML files. Also, we do not want to search through any files until we've found the last file searched for. Why spend the time opening a file and looking through its contents if we know, that we may have already listed this file? Finally, we do not want to parse through a file if its file size is zero characters, because doing so will cause an error!

If we do reach a point where we want to search through a file (that is, the file has the proper extension, we have already found the last file, and the filesize is greater than zero bytes, then we want to use the FileSystemObject to open up the text file, reading in the contents of the file into a single string variable. The following code will perform these checks and, if the current file passes thse checks, the contents will be read into a string variable, strContents:

'Do we need to search this file? If UCase(Right(objFile.Name,6)) = ".SHTML" then If bolLFFound then if objFile.Size > 0 then 'Read the contents of the file into a string variable Set objFSO = Server.CreateObject("Scripting.FileSystemObject") Set objTextStream = objFSO.OpenTextFile(objFile.Path,1) strContents = objTextStream.ReadAll objTextStream.Close Set objFSO = Nothing '... continued in next code block ...

Now that we have the contents of the file, we need to determine whether or not the terms in aLookFor exist within the contents of the file. We need to iterate from LBound(aLookFor) to UBound(aLookFor). If the user wants to search using AND logic, then each element in aLookFor must exist in the file's contents. If, however, the user wants to search using the OR logic, then only one element in aLookFor needs to exist in the file's contents. The following For statement will determine whether or not a file is valid - that is, if the file has the terms needed to satisfy the conditions specified by the boolean logic and the search terms. Also, if the file is valid, a link to the file is displayed.

if bolAnd then bolValid = True else bolValid = False For iLoop = 0 to iUBound If InStr(1,strContents,aLookFor(iLoop),1) then if Not bolAnd then bolValid = True Else If bolAnd then bolValid = False End If Next If bolValid then 'Display the file as a hit Response.Write objFile.Name & "<P>" 'Increment the # of files found iCount = iCount + 1 End if '... code continued in next code block ...

The For loop iterates through all of the elements in the array aLookFor (recall that iUBound was set to UBound(aLookFor) before our For Each ... Next loop). If the file is "valid," then we display the title and description of the file, with a link to the file. I will leave that as an exercise for the reader. (Note that each article on 4Guys has, at the top, <!--TITLE:Title-->, and Description-->. It is important that, when we find a file, we increment iCount.

What do we do when we've displayed our nth link (where n is the number of total "hits" we want to display per paged result)? At that point, we need to exit the function - no need to continue processing any files when we know we aren't going to be displaying any of them. For this reason, immediately after our display and iCount incrementation, we need to check to see if iCount is greater than iListPerPage, our constant that represents the number of links we are going to show per page. The following code will accomplish this:

If iCount > iListPerPage then strLF = FormatURL(objFile.Path) exit function End If '... continued in next code block ...

Note that, if we have listed all of our links, we need to set strLF to the URL of the final file we processed. The FormatURL function takes a physical path and translates it into a URL-type path. We'll look at this function in a bit.

Earlier in our For Each ... Next loop, we checked to see whether or not bolLFFound was True or not. If it was, we processed the file. If it is False, that means we have not yet reached the last link showed on the previous search page. If it is currently False, we need to check whether or not we need to make it True now. All we do is compare strLF to the current file name. If they match, then it is time to set bolLFFound to True. The following code example will do that for us:

Elseif FormatURL(objFile.Path) = strLF then bolLFFound = True End If End if Next '... continued in next code block ...

We have now completed our For Each ... Next loop! We still need to recurse through all of the subfolders, though, so we need to loop through each subfolder of objFolder, recursively calling GetFiles. If you're unfamiliar with recursion, you really should read Recursion, Why it's Cool. The following code will iterate through each of the subfolders of objFolder, and each of those subfolder's subfolders and so on. Once we've done this, we're done with our function, GetFiles. Here's the final code:

Dim objSubFolder For Each objSubFolder in objFolder.SubFolders GetFiles objSubFolder,aLookFor,strLF,bolLFFound,bolAnd,iCount Next End Function

Note that we recursively pass GetFiles all of the same variables. This concludes our examination of the code for search.asp. We still need to look at the function FormatURL, and we also need to look at displaying our search results and providing the Show more results link! We'll tackle these issues in Part 4.

  • Read Part 4
  • Read Part 2
  • Read Part 1


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