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Published: Friday, June 16, 2000

Creating a Persistent Web Page Counter, Part 2

By John Sgro


  • Read Part 1

  • In Part 1 we looked at the PageTotals.txt file, which acted as a surrogate database, containing all of the page hit count information. Now onto the actual file that will be included in all our pages and which does all our site counter "work". First let's take a look at the complete PageCounters.asp file and then we'll go over it step by step and explain what it's doing...

    - continued -

    The complete code for PageCounters.asp can be seen here. Let's break it down into chunks to see what's it's doing (and so that we can learn how to use some of this stuff in future applications!)...

    <%
    Dim x
    Dim FSObject
    Dim GetTotals
    Dim WriteTotals
    Dim PageEntry
    Dim PageHits()
    Dim PageName()
    Dim ThisPage
    
    'What page are we on?
    ThisPage = Request.ServerVariables("URL")
    
    Set FSObject = CreateObject("Scripting.FileSystemObject")
    Set GetTotals = FSObject.OpenTextFile("d:\InetPub\wwwroot\PageTotals.txt",1,0)
    

    After declaring our variables and arrays, we set the ThisPage variable equal to the value of Request.ServerVariables("URL"). Request.ServerVariables("URL") contains the full virtual path to the currently executing ASP page. This variable, then, will indicate what page needs to have its hit count incremented. Next we create a FileSystemObject and store it in the FSObject variable. Now comes the fun stuff! We use the OpenTextFile method of FSObject to open up a "text stream" to our PageTotals.txt file for reading. That sounds confusing, but all it means is that we now have a method of stepping through each line of our text file and doing something with the output...very much like the way you would step through each record of a database after you open up a recordset. Pretty cool, don't ya think?

    OpenTextFile takes three arguments. The first is the path to where the PageTotals.txt file is located. The second argument is the I/O MODE we are going to use. The 1 simply means that we are opening the file to READ its output. The third argument is the FORMAT of the text. Using 0 just specifies that the data is in ASCII format (which is adequate in most cases). We use the GetTotals variable to get at our text stream data. And now that we have that info from our text file, let's use it for something!

    This next snippet is the part of our script that actually finds which page count we need to adjust and display to our visitor.

    x=0
    While Not GetTotals.AtEndOfStream
    

    While Not GetTotals.AtEndOfStream is pretty straight-forward. All it says is that we're going to step through our text file until we reach the end.

      ReDim preserve PageName(x)
      PageName(x) = GetTotals.ReadLine
    

    Next we set up a dynamic array, PageName(), which will hold all of our site's page names. Don't forget to use preserve...we don't want to overwrite our array on the next loop through! PageName(x) = GetTotals.ReadLine takes the first line of our text file and stores it as the first element of the array.

      If PageName(x) = ThisPage Then
        ReDim preserve PageHits(x) 
        PageHits(x) = GetTotals.ReadLine + 1
        DisplayCount = PageHits(x)
        x = x + 1 
    

    Now we are going to see if this is our current page. Remember how we declared a variable called ThisPage at the top of PageCounters.asp? We're going to use it now and see if it matches our PageName(0) element. If it does we have to increase our hit total by 1 and store it in the PageHits() array.

    That ReadLine that we used a minute ago to read our page name did one other thing for us. It conveniently skipped down to the next line in our text file. We're sitting right at our page hit total! If we have a match then PageHits(x) = GetTotals.ReadLine + 1 stores the hit total into our array after upping it by 1. We also set DisplayCount = PageHits(x) so that we can display the counter on our page later. x = x + 1 simply increments our array index so that we can store the rest of our text file info as we loop through. And once again ReadLine has dropped us to the next line of our text file...the next page name on our site.

      Else
        ReDim preserve PageHits(x) 
        PageHits(x) = GetTotals.ReadLine 
        x = x + 1   
      End If
    Wend  
    
    GetTotals.Close 
    Set GetTotals = Nothing
    

    Let's say we didn't have a page match. We do ALMOST EXACTLY the same thing, except we read the hit total in without bumping it up by one. (And we don't set our DisplayCount variable, of course!) So, PageHits(x) = GetTotals.ReadLine. The count remains the same... ReadLine puts us at our next page name.

    We keep looping like this until we reach the end of the text stream. All the page names are now loaded into our PageName() array and all the counts are loaded into our PageHits() array. Remember, only ONE total, the count for THIS PAGE was increased by one. Now that we have all our info, we can clean-up and Set GetTotals = Nothing. Still with me? I hope so. We're almost done. :)

    The final step of our procedure is to take all of our page counter totals and write them back into the text file so that they are available for the next visitor that hits the site. This isn't hard at all since we have that info stored in our PageName() and PageHits() arrays. And we're going to call another method of the FileSystemObject to do the work for us...

    Set WriteTotals = FSObject.CreateTextFile("d:\InetPub\wwwroot\PageTotals.txt")
    

    Similar to the OpenTextFile method that we used at the beginning, FSObject.CreateTextFile allows us to take a stream of data and create a text file out of it. We'll essentially just be re-creating our original text file with our adjusted page total. As we did with OpenTextFile, we have to specify the path and name of the file... but that's it. No other arguments are needed. We will just call it PageTotals.txt again so that the "old" text file is overwritten with the new data.

    x = 0  
    For Each PageEntry In PageName 
      WriteTotals.WriteLine PageName(x) 
      WriteTotals.WriteLine PageHits(x) 
      x = x + 1 
    Next
    

    I'm sure you've figured-out what is happening here. We're just looping through both our arrays and letting WriteTotals.WriteLine list our info back into our text file. WriteLine is similar to ReadLine in that after it writes each line of text to the file, it skips down one line before entering the next piece of data. Voila... a new PageTotals.txt!

    WriteTotals.Close   
    Set WriteTotals = Nothing
    Set FSObject = Nothing
    

    And we JUST GOTTA clean-up! :) And don't forget that we have to show our guest their visitor number. You remember how we stored this page's new hit total in the DisplayCount variable way back there when we were having fun loopin' and readin', right? So just drop the following snippet of code wherever you want on the page.

    Response.Write("<font size=2><b>You are " & ThisPage & _
                   " Page visitor number...</b></font><br>" & _
                   DisplayCount & "</font>")
    

    That's it! We have a way to keep track of all the hits to every page on our site. And we did it all with a simple text file, our PageCounters.asp include file. Kinda like a database for people who don't have a database, huh?

    I hope my fellow "ASP rookies" learned something from this article. I enjoyed writing it! I'm sure that the pros out there probably know of ways to do some of this stuff much quicker or easier, but sometimes we new guys just have to hack it out whatever way we can, you know? :)

    I'd be happy to hear whatever feedback or suggestions you may have...good, bad or otherwise. And THANKS to 4 Guys for giving me a chance to play "teacher" for a little while!

    Happy Programming!

  • JohnSgro


    Attachments

  • Download the source for PageCounters.asp in text format


    Suggested Readings

  • FileSystemObject F.A.Q.
  • Read the FileSystemObject technical docs.
  • Building a Simple Hit Counter in ASP
  • Read Improving the Persistent Page Counter


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