xml node exists using variables in powershell

Question

I am trying to determine if a Mailbox with a certain DisplayName exists in my powershell script (see example xml below). I can find the node if I hard-code the value, but I have not been able to pass this value as a parameter. I have tried various ways of escaping, using single quotes and double, but none of it is going the right way.

The ultimate goal is to create the Mailbox node if one doesn't exist with the same DisplayName. There may be 0 or more Mailbox nodes.

Here's a sample xml:

<Profiler>
  <Mailboxes>
    <Mailbox>
      <DisplayName>django</DisplayName>
    </Mailbox>
  </Mailboxes>
</Profiler>

This is the piece of code, I want executed if the node doesn't exist:

$newMailbox = $xmlData.CreateElement("Mailbox")
$newDisplayName = $xmlData.CreateElement("DisplayName")
$newDisplayNameText = $xmlData.CreateTextNode($mailboxName)
$newDisplayName.AppendChild($newDisplayNameText)
$newMailbox.AppendChild($newDisplayName)
$mailboxes = $xmlData.SelectSingleNode("./Profiler/Mailboxes")
$mailboxes.AppendChild($newMailbox)

This piece of code works:

$users = $xmlData.SelectNodes("./Profiler/Mailboxes/Mailbox/DisplayName[text() = 'django']")
write-host $users.count

output from script: 1

This doesn't:

$mailboxName = "django"
$users = $xmlData.SelectNodes("./Profiler/Mailboxes/Mailbox/DisplayName[text() = $mailboxName]")
write-host $users.count

output from script: 0

I also tried this:

$mailboxName = "django"
$users= $xmlData.SelectNodes("./Profiler/Mailboxes/Mailbox[DisplayName = $mailbox]")

output from script: Exception calling "SelectNodes" with "1" argument(s): "Expression must evaluate to a node-set."

Martin Honnen · Accepted Answer · 2015-02-19 18:06:52Z

1

I think you want $users = $xmlData.SelectNodes("./Profiler/Mailboxes/Mailbox/DisplayName[. = '$mailbox']").

answered Feb 19, 2015 at 18:06

Martin Honnen

169k6 gold badges100 silver badges122 bronze badges

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

2 Comments

Jørgen Lund Over a year ago

According to ss64.com/ps/syntax-esc.html and from what I've seen, it won't work - anything inside a single-quoted string won't be evaluated. And if I try double quotes, I get new errors

Martin Honnen Over a year ago

In my understanding the powershell string in my code samples is delimited by double quotes so powershell will do variable interpolation. The single quotes are inside the double quoted string, and they are in their for XPath, so that the argument passed to SelectNodes will be the string ./Profiler/Mailboxes/Mailbox/DisplayName[. = 'jango'] and not the string ./Profiler/Mailboxes/Mailbox/DisplayName[. = jango] as the latter would compare DisplayName to an XML element named jango and not the string value jango.

Collectives™ on Stack Overflow

xml node exists using variables in powershell

1 Answer 1

2 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

2 Comments

Your Answer

Sign up or log in

Post as a guest

Related