Appending multiplelines or "nodes" to an XML document correctly-CodePudding

Lets say I have an .xml that currently looks like this:

<?xml version="1.0"?>
<button backcol="none" display="label" label_pos="right" separate="yes" textcol="none">
  <label>MultiLine</label>
  <tip>Opens an Explorer window for the current folder</tip>
  <icon1>#folder</icon1>
  <function type="normal">
    <instruction>Hello 0</instruction>
  </function>
</button>

I would like to use Powershell to replace any "instruction" nodes the input has, so an output of the above xml could look like:

<?xml version="1.0"?>
<button backcol="none" display="label" label_pos="right" separate="yes" textcol="none">
  <label>MultiLine</label>
  <tip>Opens an Explorer window for the current folder</tip>
  <icon1>#folder</icon1>
  <function type="normal">
    <instruction>Hello 1</instruction>
    <instruction>Hello 2</instruction>
    <instruction>Hello 3</instruction>
  </function>
</button>

I wrote a function to achieve this:


function DopusML {
    [CmdletBinding()]
    param(
        [Parameter(ValueFromPipeline)]
        $InputObject
      )

    Process{
        $OutXML    = "C:\Temp\MultiLine.dcf"
        $MultiLine = [xml](Get-Content "C:\Temp\MultiLine.dcf")
    
        $InputObject -split "\n" | foreach-object {
            $CurrentLine = $_
            select-Xml -Xml $MultiLine -XPath "//button[label='MultiLine']//instruction" | % {$_.Node.InnerXml = "$CurrentLine"}
        }
        $MultiLine.Save($OutXML)
    }
}

Doing Something like:

"Hello 1
Hello 2
Hello 3" | DopusML

Gives me the output:

<?xml version="1.0"?>
<button backcol="none" display="label" label_pos="right" separate="yes" textcol="none">
  <label>MultiLine</label>
  <tip>Opens an Explorer window for the current folder</tip>
  <icon1>#folder</icon1>
  <function type="normal">
    <instruction>Hello 3</instruction>
  </function>
</button>

Meaning only the last line is saved, instead of all the lines I thing my propblem lies at:

select-Xml -Xml $MultiLine -XPath "//button[label='MultiLine']//instruction" | % {$_.Node.InnerXml = "$CurrentLine"}

so I tried:

select-Xml -Xml $MultiLine -XPath "//button[label='MultiLine']//instruction" | % {$_.Node.InnerXml = "$CurrentLine"}

As well as:

select-Xml -Xml $MultiLine -XPath "//button[label='MultiLine']//instruction" | % {$_.Node.InnerXml = @($CurrentLine)}

The articles I have been reading dont really go into depth into this issue and am out of idea as well.

Any help or ideas, would be really appreciated!

CodePudding user response：

Edit

As per your comment, I have added a switch -Append to the function.
without specifying this when calling the function, all already present nodes will first be removed.
with specifying switch -Append when calling the function, new nodes will be added, leaving already present nodes untouched

function DopusML {
    [CmdletBinding()]
    param(
        [Parameter(ValueFromPipeline = $true)]
        [string]$InputObject,

        [switch]$Append
    )

    $file = "D:\Test\MultiLine.dcf"  # should this be hardcoded?
    # load the xml file. This way, you are ensured to get the file encoding correct
    $xml = [System.Xml.XmlDocument]::new()
    $xml.Load($file)

    if (!$Append) {
        # you want to first remove the already present instruction nodes
        $xml.DocumentElement.function.ChildNodes | Sort-Object -Descending | ForEach-Object {
            [void]$_.ParentNode.RemoveChild($_)
        }
    }
    foreach ($string in ($InputObject -split '\r?\n')) {
        $newNode = $xml.CreateElement('instruction')
        $newNode.InnerText = $string
        [void]$xml.DocumentElement.function.AppendChild($newNode)
    }

    $xml.Save($file)
}

Then calling it with

@"
Hello 1
Hello 2
Hello 3
"@ | DopusML

would result in

<?xml version="1.0"?>
<button backcol="none" display="label" label_pos="right" separate="yes" textcol="none">
  <label>MultiLine</label>
  <tip>Opens an Explorer window for the current folder</tip>
  <icon1>#folder</icon1>
  <function type="normal">
    <instruction>Hello 1</instruction>
    <instruction>Hello 2</instruction>
    <instruction>Hello 3</instruction>
  </function>
</button>