Add Group to Folder in a Document Library using Powershell

Question

I want to create a Function with a single command line to add a SP Group to a Folder within a Documents Library.

Structure:

• Site
  • Document Library
    • Folder (Permissions/Group(s) to be added here)
      • Items (Documents)

I have...

function Add-SPPermissionToListGroup
{
param ($Url, $ListName, $GroupName, $PermissionLevel)
$web = Get-SPWeb -Identity $Url
$list = $web.Lists.TryGetList($ListName)
if ($list -ne $null)
{
    if ($list.HasUniqueRoleAssignments -eq $False)
    {
        $list.BreakRoleInheritance($True)
    }
    else
    {
        if ($web.SiteGroups[$GroupName] -ne $null)
        {
            $group = $web.SiteGroups[$GroupName]
            $roleAssignment = new-object Microsoft.SharePoint.SPRoleAssignment($group)
            $roleDefinition = $web.RoleDefinitions[$PermissionLevel];
            $roleAssignment.RoleDefinitionBindings.Add($roleDefinition);
            $list.RoleAssignments.Add($roleAssignment)
            $list.Update();
            Write-Host "Successfully added $PermissionLevel permission to $GroupName group in $ListName list. " -foregroundcolor Green
        }
        else
        {
            Write-Host "Group $GroupName does not exist." -foregroundcolor Red
        }
    }
}
$web.Dispose()
}

...which I got from Add group to Library permissions using powershell

Q: How do I modify the above to get what I need? I have tried a few things but no success.

TIA

Answer 1

All you need to change is the object where you add new role assignment, in you case: - change list to folder. Your modified script:

function Add-SPPermissionToFolderGroup
{
    param ($Url, $sourceFolder, $GroupName, $PermissionLevel)
    $web = Get-SPWeb -Identity $Url

            // $sourceFolderGets the folder that is located at the specified URL.
            $folder = $web.GetFolder($sourceFolder)
            $group = $web.SiteGroups[$GroupName]
            $roleAssignment = new-object Microsoft.SharePoint.SPRoleAssignment($group)
            $roleDefinition = $web.RoleDefinitions[$PermissionLevel];
            $roleAssignment.RoleDefinitionBindings.Add($roleDefinition);

            // 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();
    $web.Dispose()
}