May, 2008

VBScript Statements: Explanation of the Option Explicit Statement

In VBScript declaring your variables up front is not required (as stated in this sites explanation of the Dim Statement), however, many programmers choose to declare their variables up front to avoid having to track down misspellings in their code. They go further by adding the Option Explicit statement to force them to do so. With Option Explicit turned on and error is thrown when a variable is used before being declared.

Consider the following code, that doesn’t use Option Explicit:

TheFirstVariable = 1
TheSecondVariable = 2
TheThirdVariable = TehFirstVariable + TheSecondVariable

Wscript.echo TheThirdVariable

The output will be 2, when you were expecting 3! To find the error, if you didn’t notice it, read the third line very slowly TheFirstVariable is spelled differently as TehFirstVariable– therefore creating a new variable with a default value of zero. (or empty if used as a string)

VBScript Statements: Explanation of the Dim Statement

The DIM statement is used to declare variables prior to being used. To save space in your code, you can declare more than one variable in a single statement by separating each variable with a comma.

For example:

Dim x
Dim x, y, z

The Dim statement is not required in VBScript because VBScript will automatically create variables at the time you first use them.

VBScript Statements: Explanation of the Const Statement

The Const statement is useful when you want to reference a specific, unchanging, value in your code multiple times without typing it over and over.

For example, in order to use the Const Statement to create a reference to the value of pi to 50 decimal places, you use the following code:

Const pi = 3.14159265358979323846264338327950288419716939937510

The important thing to remember is that, constants can not be changed once set in your code– Doing so will result in an error being thrown.

Sending e-mails with VBScript using the cdo.sys object

Writing text files, Word docs, Excel spreadsheets with VBScript is great and all– but sometimes you just need a process to run and notify you when something happens. (Without remembering to check a file every day.) In fact, sometimes it’s nice to walk in and receive an email in your inbox to remind you– or let you know all is well in the world.

 To accomplish this on windows 2003 and above the CDOSYS object is our best friend. There are a few caveats to using this script though. Note that (as I recall) CDOSYS is not available prior to Windows 2000, so if you’re running windows NT 4.0 you’ll need to use CDO.NTS instead, which is slightly different in syntax. Also, the object is installed as part of the SMTP service, so you will need the SMTP service installed on the system this script runs on to make it work. (Yes, it will work on Windows XP as well with the SMTP service installed.)

Using CDOSYS is really easy. Basically, you create the CDO.Message object and then set 4 properties (TO, SENDER, TEXTBODY, and SUBJECT) then call the SEND method to actually do the sending of emails. Literally, it’s that simple. If you don’t believe me, check out the following code:

      dim oMail
      set oMail = CreateObject(”CDO.Message”)
      oMail.To = “myemail@somedomain.com“
      oMail.Sender = “anotheremail@anotherdomain.com“
      oMail.TextBody = “Your ticket has been submitted.”
      oMail.Subject = “CDO.SYS Test”
      oMail.Send        
      set oMail = nothing
      WScript.Echo “Message was sent.”        

Simple enough, right?!?! For further information about this object you can check out the following Google search.

As always, this code works perfectly. However, sometimes the formatting of the blog breaks the code if you copy and paste it into your editor. So, if you’d like to not type or troubleshoot any syntax errors due to the copy and paste problems– I’ve provided the code for download, plus example output files  from my final tests for you. You’ll find the code and other files available for download from my website’s (www.webstemsadministration.com) File Depot under the ITKE Blog Scripts category. Enjoy and happy scripting!

VBScript Statements: Explanation of If… Then … Endif

The If/Then/Else statement in VBScript is very similar to the Select Case statement, except it only normally allows for 2 possibilities in your condition.  Basically, the If/Then statement says– It is or it isn’t.

It very useful for testing a specific value to see if it is equal to, greater than, or less than something else and doing something based on the outcome of the condition. The statement always evaluates the expression based of if the condition is true. For example, this code would always run, because the condition would always be true:

x=1
if x=1 then
‘do something
endif

While this code would never run:

x=1
if x>1 then
‘do something
endif

The else option is a useful tool as well, it applies to all other conditions should the if test expression(s) not be true. This allows for code to run under only certain situations, depending on the value of the expression:

x=1
if x=1 then
‘do something
else
‘do something else for all other possibilities
endif

Optionally, there is a elseif component of the statement that can include another condition. However, if you start to need more than more than one of these a select/case statement is likely a better option. Consider this example:

if x=1 then
‘do something
elseif x=0
‘ do something else
elseif x=2
‘ do another something else
elseif x=3
‘ do something completely different
else
‘do something else for all other possibilities
endif

In this last case, the important thing to remember is the only part of the code that runs is the where the expression best fits and only ONE section is executed.

Getting disk usage data with the filesystem object and the Excel.Application object in VBScript

In my previous posting, entitled Working with the Excel.Application object in VBScript to create Excel Spreadsheets, we worked with excel in VBScript to create a excel spreadsheet. The spreadsheet wasn’t going to win any awards for complexity or usefulness, but none the less it was a spreadsheet– and more importantly it was generated by a script! I also promised to bring you a script to help you chart disk space usage in my next posting in the series. This posting is the fulfilment of that promise! Also, please note that you will need Excel installed where the script runs for this script to operate correctly– but it does not need to be installed on the system you are pulling disk free space information from since I used the WMI object instead of the filesystem object.

The script below uses WMI’s Win32_LogicalDisk class to grab the drives in the target system, specifically the drive you specify through the use of a where clause in the SQL statement that pulls back the WMI data. (Through the “where deviceid like” section of the SQL statement in the code)

 Also, I didn’t put a lot of effort into the code where the for/next loop is that loops through getting and saving the free space because I didn’t want to create a lot of extra complexity and wanted to create a script that would run through to completion pretty quickly. Currently, the script takes 10 minutes to complete. To test the script while it’s running, just create files in a folder and delete them a number of times. I created a 10Mb and 20Mb file and made a series of copy/pastes during execution– with a smattering of deletes in the mix.

For further customization, you can look at the code from the posting I wrote a while back Reporting CPU usage by saving it to a file with the VBScript filesystem object to get a good feel for how to modify the loop to get what you want. In essence, change the number 2 in “Wscript.Sleep 2″ to a lager number to get a bigger gap between samples and change the 300 in the “For x = 1 to 300″ line to a larger number to get a longer sample period.

Here is the code:
Dim Freespace, CurrentRow, ServerName
Const xlSaveChanges = 1

‘the first row in excel is 1 (not 0)
CurrentRow = 1
ServerName=”.”

Set objExcel = CreateObject(”Excel.Application”)
objExcel.Visible = False
objExcel.Workbooks.Add
For x = 1 to 300 ‘ change 300 to increase your sample duration
     objExcel.Cells(CurrentRow, 1).Value = GetFreeSpace(”C:”,ServerName)
     CurrentRow = CurrentRow + 1
     Wscript.sleep 2 ‘change this to spread out your samples
next

objExcel.ActiveWorkbook.SaveAs (”C:\excelvbscript.xls”)
objExcel.Quit
Function GetFreeSpace(Drive,strComputer)
     Set objWMIService = GetObject(”winmgmts:{impersonationLevel=impersonate}!\\”_
         & strComputer & “\root\cimv2″)
     Set colDisks = objWMIService.ExecQuery (”Select * from Win32_LogicalDisk where deviceid like “_
         &chr(34) & Drive & chr(34))
     For Each objDisk in colDisks
         GetFreeSpace = (objDisk.freespace/1024)/1024 ‘ get MB free
     Next
End Function

As always, this code works perfectly. However, sometimes the formatting of the blog breaks the code if you copy and paste it into your editor. So, if you’d like to not type or troubleshoot any syntax errors due to the copy and paste problems– I’ve provided the code for download, plus example output files  from my final tests for you. You’ll find the code and other files available for download from my website’s (www.webstemsadministration.com) File Depot under the ITKE Blog Scripts category. Enjoy and happy scripting!

VBScript Statements: Explanation of Select … Case

The Select … Case VBScript statement is a very powerful way to easily preform specific actions based on a comparison of a variable to a series of cases you specify, plus it allows for the fact that NONE of the cases apply with an optional case else condition. The Select Case statement is often a better solution then a if…Then…Else if when you have more than 2 conditions that could apply.

Consider the following code snippet to check if a number is positive or negative:

Function TestNumber(Number)

Select case Number
Case Number > 0
TestNumber = “Positive”
Case Number < 0
TestNumber = “Negative”
Case Else
TestNumber = “Zero”
End Select

Working with the Excel.Application object in VBScript to create Excel Spreadsheets

In my previous two postings we discussed the Microsoft Word.Application object (here and here) to use as a logging mechanism and as a documentation mechanism for our scripts we’re writing.

But what about if you wanted to log numbers, like in the performance counter posts I made a few weeks back? I’ve also seen several questions about how to do use excel in VBScript. Well, it’s super easy, once you get the object understood. The next few postings I’ll focus on this great way to save data in a format that is easily shareable and can easily be made into pretty pie charts and such for the boss.

First off I’ll give you a simple example that basically creates the object (not visible), adds a new workbook to it, adds a string to cell 1,1, and finally saves it before it quits. Below is the example code for this scriptlet:

Const xlSaveChanges = 1

Set objExcel = CreateObject(”Excel.Application”)
objExcel.Visible = False
objExcel.Workbooks.Add
objExcel.Cells(1, 1).Value = “Test value”
objExcel.ActiveWorkbook.SaveAs (”C:\excelvbscript.xls”)
objExcel.Quit

I’ll dig deeper right after I go back and explain the Select Case statement I used in a previous posting– which I neglected to mention previously or explain in the posting. (Bad, Jerry, Bad Bad.) However, after that I promise to come back with a more specific example of Excel.Application, but this should give you a little bit to play with in the mean time.

As always, this code works perfectly. However, sometimes the formatting of the blog breaks the code if you copy and paste it into your editor. So, if you’d like to not type or troubleshoot any syntax errors due to the copy and paste problems I’ve provided the code for download, plus example XML files and Generated Word Documents for you. You’ll find the code available for download from my website’s (www.webstemsadministration.com) File Depot under the ITKE Blog Scripts category. Enjoy and happy scripting!

Easily document group policy objects in Microsoft Word using VBScript with the Microsoft.XMLDOM and Word.Application objects

OK, here is the posting I hinted at in  my previous posting this week entitled, Using VBScript to create Word documents automatically with the Word.Application Object. In that posting I mentioned a project where I had to create a ton of documentation… but I didn’t say what it was that I had to document. Yeah, you guessed it from this article’s title… Group Policy Settings! I had to document settings in a series of policies I was proposing we implement at my employer. Here is the scenario:

I was asked “Can you document all the settings you are proposing in the new policies for the other members of IT? Also, Can you document the name of the setting, what you want it to be and what options are available to change it to? Oh, and what each value means when you set it?…. Do you think you’ll have time to also let us know for each setting what the supported or intended OS version is for the setting? I need it by Friday.”

Now, much like you might do, I said “I’ll try.” and mumbled under my breath later “If you bring me a pound of Lead I’ll turn it to Gold too!”… None the less, after my initial pity party, I began looking at the Information available to me in the Group Policy Management Console (Available here if you don’t have it already.), much to my surprise I found almost everything I needed when I looked at the individual settings… it just wasn’t in a format I could show to people or they could read easily. So I set out to try and copy and paste the information into word… for 20 seconds… and realized this is way to much work! And what do I always say??????   Be Lazy!

Now I looked at the options available to me on exporting the file and CSV was one of them, but unfortunately all the relationships were lost and I couldn’t make heads or tails of how to cobble it back together in a meaningful way after the export. Then I noticed XML and remembered my last post on Microsoft.XMLDOM (Using XML in VBScript via Microsoft.XMLDOM to work with data feeds) and thought, I really need to get back to that… so here we are!

First, Just like my last post– you’ll need Microsoft Word installed where you run this script for it to operate. Then you’ll need to use The Group Policy Management console to export the policy settings to XML. (hover over the icons along the top, it’s the one with the icon that looks like a page of paper with an arrow pointing right, one of the save as options is XML.) Save this file into the location where the script is located (I recommend a descriptive name, because it will be the heading for your document.) and with a single edit of the script you will have a word doc on the root of your C: drive with the same name— only documented in Word!

The script basically opens and reads in the XML Document and creates a Word.Application object to create a Microsoft Word Document at the root of the C: Drive, then writes formatted text to the document to make the data in the XML readable. But, enough of a introduction! On to the script! Here is the script:

 set xmlDoc=CreateObject(”Microsoft.XMLDOM”)
Set objWord = CreateObject(”Word.Application”)
Set objDoc = objWord.Documents.Add()
Set objSelection = objWord.Selection

‘This is the actual name of the XML document minus the path and the “.XML” extension, it becomes the word doc header
xmlfile = “Locked Down Desktop Policy”

objSelection.Font.Name = “Arial”
objSelection.Font.Size = “18″
objSelection.Font.Bold = True
objSelection.TypeText xmlfile & VbCrLf

objSelection.Font.Bold = False
objSelection.Font.Size = “10″

xmlDoc.async=”false”
xmlDoc.load(xmlfile &”.xml”)
for each x in xmlDoc.documentElement.childNodes
If x.nodename = “Computer” or x.nodename = “User” Then
For Each y In x.childnodes
if y.Nodename = “ExtensionData” then
For Each z In y.childnodes
If z.Nodename = “Extension” Then
For Each setting In z.childnodes
objSelection.TypeText “______________________________________” & vbCr
DocumentPolicy(Setting)
Next
End if
Next
End if
Next
End If
Next
objDoc.SaveAs(”C:\” & xmlfile & “.doc”)
objWord.Quit
Function DocumentPolicy(Setting)
‘this function basically cleans up the headers of the word document, so they are more human readable
Select Case setting.nodename
Case “q1:Policy”
replacestr = “q1:”
Case “q1:DropDownList”
replacestr = “q1:”
Case “q1:Name”
replacestr = “q1:”
Case “q1:Value”
replacestr = “q1:”
Case “q1:State”
replacestr = “q1:”
Case “q2:Audit”
replacestr = “q2:”
Case “q2:SecurityOptions”
replacestr = “q2:”
Case “q2:EventLog”
replacestr = “q2:”
Case “q2:RestrictedGroups”
replacestr = “q2:”
Case “q2:File”
replacestr = “q2:”
Case “q2:Display”
replacestr = “q2:”
Case “q3:General”
replacestr = “q3:”
Case “q3:HashRule”
replacestr = “q3:”
Case “q3:PathRule”
replacestr = “q3:”
Case “q3:InternetZoneRule”
replacestr = “q3:”
Case “q4:AutoEnrollmentSettings”
replacestr = “q4:”
Case “q4:AutoEnrollmentSettings”
replacestr = “q4:”
Case “q4:RootCertificateSettings”
replacestr = “q4:”
Case “q4:EFSSettings”
replacestr = “q4:”
Case “q5:PreferenceMode”
replacestr = “q5:”
Case “q2:PreferenceMode”
replacestr = “q2:”
Case “q2:ProxySettings”
replacestr = “q2:”
Case “q2:UseSameProxy:”
replacestr = “q2:”
Case “q2:HTTP:”
replacestr = “q2:”
Case “q2:NoProxyIntranet:”
replacestr = “q2:”End Select
objSelection.Font.Bold = True
objSelection.TypeText VbCrLf & replace(setting.nodename, replacestr,”") & VbCrLf
objSelection.Font.Bold = False
For Each Value In Setting.Childnodes
NodeName = replace(Value.nodename,replacestr,”")
If NodeName = “Explain” Then
objSelection.Font.Bold = True
objSelection.TypeText Nodename & “: ” & vbcrlf
objSelection.Font.Bold = False
objSelection.TypeText vbTab & replace(value.text,”\n\n”, VbCrLf & VbCrLf & vbTab )& vbcrlf
Else
objSelection.Font.Bold = True
objSelection.TypeText Nodename & “: “
objSelection.Font.Bold = False
objSelection.TypeText vbtab & value.text & vbcrlf
End if
Next
If isnull(Setting.childnodes) Then
For Each node In Setting.childnodes
DocumentPolicy(node)
next
End if
objSelection.TypeText VbCrLfEnd Function

Now, when you run this script agains your export there may be some XML tags I didn’t notice because a setting you set is one I didn’t set. Any time you see them in the document you can add a new Case statement in the select case followed by setting the replacestr to the string you want to replace with a null. The lines I’m talking about look similar to this:

  Case “q2:xxxxxxxx”
replacestr = “q2:”

As always, , this code works perfectly. However, sometimes the formatting of the blog breaks the code if you copy and paste it into your editor. So, if you’d like to not type or troubleshoot any syntax errors due to the copy and paste problems I’ve provided the code for download, plus example XML files and Generated Word Documents for you. You’ll find the code available for download from my website’s (www.webstemsadministration.com) File Depot under the ITKE Blog Scripts category. Enjoy and happy scripting!