PowerShell to grant document library folder permissions

Question

In trying to discover how to grant a group permission on a document library folder I came upon the following StackExchange article:

Add Group to Folder in a Document Library using Powershell

I have implemented a "test" version for my purposes before applying it to my code.

function Add-SPPermissionToFolderGroup
{
    param ( $Site, $CommitteeSite, $SourceFolder, $GroupName, $PermissionLevel )

    #$sourceFolderGets the folder that is located at the specified URL.
    $Folder = $CommitteeSite.GetFolder( $SourceFolder )
    $Group = $Site.SiteGroups[$GroupName]
    $RoleAssignment = new-object Microsoft.SharePoint.SPRoleAssignment($Group)
    $RoleDefinition = $Site.RoleDefinitions[$PermissionLevel];

    https://sharepoint.stackexchange.com/questions/109840/add-group-to-folder-in-a-document-library-using-powershell

    #break role inheritance for folders/files because they will be having permissions separate from their parent file/folder
    $Folder.Item.BreakRoleInheritance($true);

    #apply the new roleassignment to the folder.  You can do this at the listitem level if desired (i.e. this could be SPfile.Item.... instead of SPFolder.Item)
    $Folder.Item.RoleAssignments.Add($RoleAssignment);
    $Folder.Item.Update();
}

$Site = Get-SPWeb "https://SiteCollectionURL/"
$CommitteeSite = Get-SPWeb "https://SiteCollectionURL/Committees"
$CommitteeLib = "Committees"
$Library = $CommitteeSite.Lists[$CommitteeLib]
Add-SPPermissionToFolderGroup $Site $CommitteeSite "TRAINING_Training" "SP_TRAINING_Managers" "Contribute"

When I execute this I get an issue at line 12:

You cannot call a method on a null-valued expression. At line:12 char:5 + $Folder.Item.BreakRoleInheritance($true); + ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + CategoryInfo : InvalidOperation: (:) [], RuntimeException + FullyQualifiedErrorId : InvokeMethodOnNull

I get similar issue when trying to run the code below to change the Folders' content type to "Committee"

$CommitteeLib = "Committees"
$Library = $CommitteeSite.Lists[$CommitteeLib]
$LibraryCT = $Library.ContentTypes["Committee"]
$SpFolder = $CommitteeSite.GetFolder( "Committees/Test Folder" )
$Item = $SpFolder.Item
$Item["Content Type ID"] = $LibraryCT.ID
$Itemp.Update()

The issue occurs in the second last line, and then the error is a null valued $Item.

Any ideas on where I'm going wrong.

Many thanks.

Dan

Answer 1

It is on the Item itself, not on the folder--my mistake. But the error you are getting suggests that the folder cannot be found, or is in the wrong format. Check to see if the Folder is present. Make sure $SourceFolder is a correct value.

This is not returning anything.

 $Folder = $CommitteeSite.GetFolder( $SourceFolder )  

The $SourceFolder should be in the format of the site relative url. so try this instead.

Add-SPPermissionToFolderGroup $Site $CommitteeSite "/Committees/TRAINING_Training" "SP_TRAINING_Managers" "Contribute"