Error handling in PowerShell provoked by a null dsquery

Question

I want to avoid errors provoked by a null dsquery. I tried this:

try {
     dsquery user forestroot -samid $a[$i] | dsget user -email | Select-String '@' | select -Expand Line >> output.txt
}
catch [Exception] {
    return $_.Exception.Message
}

But I'm still getting:

dsget : dsget failed:'Target object for this command' is missing.
At ExpiringCertificates.ps1:35 char:49
+         dsquery user forestroot -samid $a[$i] | dsget user -email | Select-Strin ...
+                                                 ~~~~~~~~~~~~~~~~~
    + CategoryInfo          : NotSpecified: (dsget failed:'T...nd' is missing.:String) [], RemoteException
    + FullyQualifiedErrorId : NativeCommandError

type dsget /? for help.

How should I handle it?

Are you certain you can pipe the result like you are trying to? dsquery is a command line tool and I doubt it writes object output to the pipeline like PowerShell cmdlets generally does. But of course, I might be missing something here. By the way, any special reasons you are not using the ActiveDirectory PowerShell module instead of dsquery? Is it a really old domain controller? With the cmdlets in the ActiveDirectory module you'd be working with objects the whole time instead of with output strings. — Robert Westerlund
– Robert Westerlund, Commented Apr 3, 2014 at 8:30
Yes @robert.westerlund it works. I tried to use ActiveDirectoy module however I didn't managed to query to the forestroot. I opened other post: stackoverflow.com/questions/22450817/… — srbob
– srbob, Commented Apr 3, 2014 at 8:40
It seems as though you have been given answers on how to query the forest root using the ActiveDirectory module in that question. Just read all the answers, you shouldn't provide further information on your question as answers, provide it as edits to your question and comment to an answer if it's related to the answer. — Robert Westerlund
– Robert Westerlund, Commented Apr 3, 2014 at 8:54
I tried everything they told me @robert.westerlund with no success and pasted the errors. I answered my own question twice because: a) formatting more clearly the error I got so that every reader could read it easyly. b) Solve my own question. — srbob
– srbob, Commented Apr 3, 2014 at 9:28

Peter Mortensen · Accepted Answer · 2018-11-11 05:11:12Z

1

Try this:

try
{
    dsquery user forestroot -samid $a[$i] | dsget user -email | Select-String '@' | select -Expand Line >> output.txt
}
catch
{
    Write-Error -ErrorRecord $_
}

If $ErrorActionPreference is set to 'Stop', Write-Error will throw an exception and halt execution. Otherwise, it will print to the error stream and continue execution. This allows the caller to decide whether or not to continue on error and keeps you from having to set global variables in your scripts.

If you need to print and return the error message, use the -ErrorVariable parameter:

catch
{
    $errorVar = $null
    Write-Error -ErrorRecord $_ -ErrorVariable errorVar
    return $errorVar
}

Or, if you need to return the error message without printing it, add the "2>" redirect:

catch
{
    $errorVar = $null
    Write-Error -ErrorRecord $_ -ErrorVariable errorVar 2> $null
    return $errorVar
}

edited Nov 11, 2018 at 5:11

Peter Mortensen

31.4k22 gold badges110 silver badges134 bronze badges

answered Apr 3, 2014 at 8:44

skataben

2,1821 gold badge22 silver badges27 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Peter Mortensen · Accepted Answer · 2018-11-11 05:16:19Z

1

dsquery and dsget are not PowerShell commands, so PowerShell looks at the standard error, and processes it, turning it into an ErrorRecord with a "NativeCommandError" exception attached to it, and then sends a text representation of that record to the standard output.

However, if you process the standard error yourself, you have a bit more flexibility:

dsquery user forestroot -samid $a[$i] | dsget user -email | Select-String '@' | select -Expand Line 2>&1
If ($_ -is [Management.Automation.ErrorRecord]) {
    $message = $_.Exception.Message
    # Do what you want with $message.
} Else {
    $_ >> output.txt
}

edited Nov 11, 2018 at 5:16

Peter Mortensen

31.4k22 gold badges110 silver badges134 bronze badges

answered Apr 3, 2014 at 8:47

Mark Bertenshaw

5,7093 gold badges30 silver badges43 bronze badges

Comments

Peter Mortensen · Accepted Answer · 2018-11-11 05:09:42Z

0

This might work for you:

try {
     $erroractionpreference = 'stop'
     dsquery user forestroot -samid $a[$i] | dsget user -email | Select-String '@' | select -Expand Line >output
}
catch [Exception] {
    return $_.Exception.Message
}

edited Nov 11, 2018 at 5:09

Peter Mortensen

31.4k22 gold badges110 silver badges134 bronze badges

answered Apr 3, 2014 at 8:17

saw

343 bronze badges

1 Comment

srbob Over a year ago

Hi! It partly works because it stops execution. What I need is to continue but show a controlled message such as: "User not found in AD"

Collectives™ on Stack Overflow

Error handling in PowerShell provoked by a null dsquery

3 Answers 3

Comments

Comments

1 Comment

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

Comments

Comments

1 Comment

Your Answer

Sign up or log in

Post as a guest

Linked

Related