更新子节点及其属性信息 - Powershell

Question

I am trying to update macaddress information in one of the XML files available on my servers. I see two types of situations where the

<configuration>
  <serverIdentification id="1d230d28-08bc-4a12-a56a-7dacf7f09282" />
  <NetworkBinding ReSync="false" PublicAddress="dev-000450-02a.gsccloud.ninja" PublicPort="">
   <macAddresses />
  </NetworkBinding>
.
.
.
</configuration>

or

 <configuration>
      <serverIdentification id="1d230d28-08bc-4a12-a56a-7dacf7f09282" />
      <NetworkBinding ReSync="false" PublicAddress="dev-000450-02a.gsccloud.ninja" PublicPort="">
         <macaddresses>

       </macaddresses>
      </NetworkBinding>
    .
    .
    .
    </configuration>

The desired XMLData should be the like the one shown below. Please note address(Addr) value is empty. This will get updated through some other mechanism. So don't worry about it. For now I just want the XML data to look like shown below.

<configuration>
          <serverIdentification id="1d230d28-08bc-4a12-a56a-7dacf7f09282" />
          <NetworkBinding ReSync="false" PublicAddress="dev-000450-02a.gsccloud.ninja" PublicPort="">
             <macaddresses>
              <Mac Addr="" />
           </macaddresses>
          </NetworkBinding>
        .
        .
        .
        </configuration>

From what I can see is that the child node "macAddresses" is present but the innerxml data is empty.

 $xmlfilepath  = "C\somepath\path"
    [xml] $XMLData = Get-Content -LiteralPath $xmlfilepath -ErrorAction Stop

Sorry my knowledge of XML manipulation is not that great. Any info would be greatly appreciated.

Answer 1

# Read the input file into an XML DOM.
[xml] $xmlData = Get-Content -Raw -LiteralPath $xmlfilepath -ErrorAction Stop

# Target the <macAddresses> element and add the desired child element
# via its .InnerXml property.
# Note the required use of indexing syntax (['macAddresses']).
$xmlData.configuration.NetworkBinding['macAddresses'].InnerXml = '<Mac Addr="" />'

# $xmlData is now updated; inspect with .OuterXml or save to a file
# with, say, $xmlData.Save("$PWD/new.xml")

Note: Index notation - $xmlData.configuration.NetworkBinding['macAddresses'] - rather than dot notation - $xmlData.configuration.NetworkBinding.macAddresses must be used in order to reliably target the <macAddresses> element:

PowerShell's dot notation ( .macAddresses ) is usually very convenient, but in the case of leaf elements (those that either have no content at all or text content only, except if they have attributes ), it returns the element's string content rather than the element object itself ( XmlElement ) :

• You can use dot notation to modify the text content of a leaf element (eg, $xmlData.configuration.NetworkBinding.macAddresses = 'foo' )

• You cannot use dot notation to access properties or call methods on leaf elements (eg, $xmlData.configuration.NetworkBinding.macAddresses.InnerXml = '<foo/>' fails - .macAddresses is treated as a [string] , and a string has no .InnerXml property)

  • Note that non -leaf elements are always returned as themselves ( XmlElement instances).

By contrast, index notation ( ['macAddresses'] ), a type-native feature, allows you target child elements by name as well, but consistently returns them as XmlElement objects , so you can access properties such as .InnerXml on them or call methods such as .SetAttribute() .

Note, however, that this index notation by design only ever returns the first element of that name among the children, even if multiple ones are present (which PowerShell's dot notation exposes as an array ); to target an element other than the first one , use
.SelectNodes(<name>)[<n>] on the element , where <n> is a positional index, as in an array.

In your case, since you want to add a child node to the <macAddresses> element, via assignment to the .InnerXml property, index notation is therefore required.

Answer 2

I was able to achieve this with a different solution. This is a snippet of my code which I will be using within a function.

[xml] $XMLData = Get-Content -LiteralPath $xmlfilepath -ErrorAction Stop

$appSettingsXml = @"
<macAddresses>
    <Mac Addr="" />
</macAddresses> 
"@ 


    if(($XMLData.configuration.NetworkBinding.InnerXml -eq "<macAddresses></macAddresses>") -or ($XMLData.configuration.NetworkBinding.InnerXml -eq "<macAddresses />")){
        $XMLData.configuration.NetworkBinding.InnerXml=""
        $XMLData.configuration.NetworkBinding.InnerXml=$appSettingsXml
    }
.
.
.
.
$XMLData.save($xmlfilepath)