Making SharePoint 2010 PowerShell Scripts Backward-Compatible with 2007


Recently I received an e-mail from one of my ICC SharePoint team-mates asking for some PowerShell code to create and then delete a lot of list items. Like 20000. Well, I already had code to create the list items – so it was easy to add a single line to call the delete() method immediately after the item was added.

I provided the updated function to my teammate, only to find out later that they wanted to do this in MOSS 2007 – not SP2010. Oops! I hadn’t considered that, I assumed since they were asking me for PowerShell code that they were dabbling in a 2010 environment. Not the case. However, this particular person is one of our better SharePoint Developers and quickly modified the code to work in MOSS.

After having that discussion, it became clear to me that it would be REALLY cool to create PowerShell Scripts and Functions that would work both in V4 as well as V3. And the journey began..

After some experimentation, googling, trial & error – it became apparent that this isn’t rocket science. In SharePoint 2010 we use the following PowerShell cmdlet to add the SharePoint Snap-in:

Add-PSSnapIn Microsoft.SharePoint.PowerShell

There’s no equivalent for MOSS environments, but we can load the SharePoint assemblies by using the following line of code:

[System.Reflection.Assembly]::LoadWithPartialName("Microsoft.SharePoint")

Once we’ve done that, we can do other things such as get the farm build version and tell us what version we’re working with:

function Get-SPFarmBuildVersion {
# using the [microsoft.sharepoint.administration.spfarm] line to get the local farm regardless of version #
# this works in 2007 and 2010 #
$farm = [Microsoft.SharePoint.Administration.SPFarm]::Local
$farmBuild = $farm.BuildVersion.ToString()

      if ($farmBuild.StartsWith("12")) {
      Write-Host "This is WSS or MOSS"
      } 
      
      elseif ($farmBuild.StartsWith("14")) {
      Write-Host "This is SP2010"
      }

}

How cool is that!?

Now that we know that simple tidbit, we can easily create our scripts and functions with backward compatibility in mind by doing something like if/elseif as seen above. Developers may chime in with a better way, I’m sure there are better – perhaps more elegant approaches to this same theory – but this works for me for now.

Anyhow, back to the story – my developer friend Aaron wanted to create list items in MOSS using PowerShell. Here’s the code to do that – and it’s backwards compatible!

function Add-MultipleListItems {
[CmdletBinding()]
Param(
[string]$ListName=(Read-Host "Please enter the name of the list you wish to add to."),
[string]$Amount=(Read-Host "Please enter a number of list items to create."),
[string]$Choices=(Read-Host "Please enter choices separated by semicolons, enclosed in double quotes."),
[string]$ListItem=(Read-Host "Please enter a string for the title of each list item (Example: Added by Powershell)"),
[string]$WebUrl=(Read-Host "Please enter a URL of a SharePoint site (Example: http://intranet)")
)

$choicesForCategory = $Choices -split ";"

$assemblies = [System.Reflection.Assembly]::LoadWithPartialName("Microsoft.SharePoint")
$farm = [Microsoft.SharePoint.Administration.SPFarm]::Local
$farmBuild = $farm.BuildVersion.ToString()
	
	if ($farmBuild.StartsWith("14")) {
		Start-SPAssignment -Global
		$mylist = (Get-SPWeb -identity $webUrl -AssignmentCollection $StartSpAssignment).Lists[$listName]
		Write-Host "Creating $amount list items in $listName" -ForegroundColor Green
		$i = 1
		do 
		{
		    $newItem = $mylist.Items.Add()
		    $newItem["Title"] = $listItem
		    $newItem["Category"] = $choicesForCategory | Get-Random
		    $newItem.Update()
		    $i++
		}
		while ($i -le $amount)

		Write-Host "Finished!" -ForegroundColor Green
		Stop-SPAssignment -Global
	}
	elseif ($farmBuild.StartsWith("12")) {
		$SPWeb = Get-SPWeb $webUrl
		$mylist = $SPWeb.Lists[$listName]
		Write-Host "Creating $amount list items in $listName" -ForegroundColor Green
		$i = 1
		do 
		{
		    $newItem = $mylist.Items.Add()
		    $newItem["Title"] = $listItem
		    $newItem["Category"] = $choicesForCategory | Get-Random
		    $newItem.Update()
		    $i++
		}
		while ($i -le $amount)
		$SPWeb.dispose()
		Write-Host "Finished!" -ForegroundColor Green
	}
}

If you read this line by line, you’ll notice that they are fundamentally identical. Really the only difference is in V3 we don’t get any cmdlets, so we don’t have Start-SPAssignment and Stop-SPAssignment. This just means we have to make sure we’re disciplined to use dispose() methods for any SPWeb and SPSite objects.

With all that in mind, my goal from here on out is to try and make any and all PowerShell code backwards compatible.

RD

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