Q: Catch an error in a function and continue on next string or object

[democracy77]

Hi again,

I didn’t invest enough time into error handling yet but face an issue I need to fix at the moment.

I got a function which checks against our Active Directory wether a user account, which will be provided via a .CSV file, is valid at all.

---

Here’s the code:

The .CSV file come like this:

DC = which data center

User = the user account

type = what type of virtual desktop (premium or standard)

DC,User, type
DC B,DomainA\User1,STD
DC A,DomainA\User2,STD
DC A,DomainB\User3,PRM

#################################################

FUNCTION: check if user account is a valid AD user account

#################################################
function verifyuseraccount
{
$struser = $user | select -ExpandProperty user
$usersplit = $struser -split {$_ -eq ""}
write-host “”
write-host “Checking if user account $struser is valid”

if($user -like "*DomainA*")
{
Get-ADUser $usersplit[1] -server domainA.abc.de.com
}

elseif($user -like "*DomainB*")
{
Get-ADUser $usersplit[1] -server domainB.abc.de.com
}

}

---

The problem is that sometimes the user accounts are misspelled or not existing. I currently do a manual check on the accounts from the .CSV afterwards. How can I tell the function to check for an error and if an error is thrown… sort of goto next user in the list. I remember in school we had some sort of C++ goto command but I don’t get it to work in PS.

Here’s the error when a user account cannot be validated:
Get-ADUser : Cannot find an object with identity: ‘User1’ under: ‘DC=DomainA,DC=ABC,DC=DE,DC=com’.
At C:\Users\myuserpath\Desktop\user-assignment_v2.ps1:36 char:5

• Get-ADUser $usersplit[1] -server domainA.abc.de.com
  

• ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  

  • CategoryInfo : ObjectNotFound: (User1:ADUser) [Get-ADUser], ADIdentityNotFoundException
  • FullyQualifiedErrorId : Cannot find an object with identity: ‘User1’ under: ‘DC=DomainA,DC=ABC,DC=DE,DC=com’.,Microsoft.ActiveDirectory.Management.Commands.GetADUser

regards

Christian

[mikefrobbins]

Running the users through a foreach loop with error handling should allow you to accomplish what you need. The following code should at least get you started.

#Requires -Modules ActiveDirectory
function Verify-UserAccount {

    [CmdletBinding()]
    param (
        [ValidateNotNullOrEmpty()]
        [string]$CSVPath = 'C:\tmp\users.csv'
    )
    
    $UserInfo = Import-Csv -Path $CSVPath

    foreach ($User in $UserInfo) {
        Write-Verbose -Message "Checking if user account $($User.User) is valid."
        
        try {
            Get-ADUser -Server $User.DC -Identity ($User.User -replace '^.*\\') -ErrorAction Stop
        }
        catch {
            Write-Warning -Message "No such user: $($User.User)"
        }
    }

}

[democracy77]

Hi Mike,

thanks for the quick reply. This really got me further.

Although my “verify user function” does now cycle through each user, when I embed it into my script the script still continues even if the output of the “verify user function” is negative meaning that this user is invalid.

Is there a catch for a function within a script as well to catch that negativ output and goto next user in line?

This is a part of the script I’m talking about:

foreach ($user in $users)
{
#DC A (DCN) path
if($user.DC -eq “DC A”)
{
verifyuseraccount

!----> How can I catch the error from the function verifyuseraccount and on error goto next user in list? <-----!

checkforvdi

    if($user.type -eq "STD")
    {
    #get all not assigned machines from XenDesktop
    $Xdcomputer = $dcnadcomputer | foreach {get-brokermachine -hostedmachinename $_  -IsAssigned $false -AdminAddress $adminaddress -MaxRecordCount 9999 | where {$_.CatalogName -notlike "*sDD*" -and $_.CatalogName -like "*STANDARD*"}}
        
        #Check if any VDIs are available to assign
        if($Xdcomputer.count -gt 0)
        {
        $randomset = get-random -InputObject $Xdcomputer -Count 1
        }
        else
        {
        write-warning "No more $user.type VDIs are availabe in $user.DC, continueing with next user."
        break
        }    
    }
    Elseif($user.type -eq "PRM")
    {
    #get all not assigned machines from XenDesktop
    $Xdcomputer = $dcnadcomputer | foreach {get-brokermachine -hostedmachinename $_  -IsAssigned $false -AdminAddress $adminaddress -MaxRecordCount 9999 | where {$_.CatalogName -notlike "*sDD*" -and $_.CatalogName -like "*PREMIUM*"}}
    
        #Check if any VDIs are available to assign
        if($Xdcomputer.count -gt 0)
        {
        $randomset = get-random -InputObject $Xdcomputer -Count 1
        }
        else
        {
        write-warning "No more $user.type VDIs are availabe in $user.DC, continueing with next user."
        break
        }    
    }
    Else
    {
    write-warning "No VDI found"
    }

regards

Christian

[democracy77]

Mike,

I think I found what I was looking for…

I added continue

try
{
Get-ADUser $usersplit[1] -server domainA.abc.de.com
}
catch
{
Write-Warning -Message “No such user: $($User.User)”
continue
}