Parsing XML with namespace with PowerShell

I was able to get the data I need with the "object" way:

$product = $xml.catalog.product | Where-Object {$_."product-id" -eq "50610"}
$of = $product."online-flag"
$glblsid = $of | Where-Object {$_ -is [System.String]}
$specsid = ($of | Where-Object {$_."site-id" -eq "ru"})."#text"

But I don't like the way I managed to do this. Is there a more convenient solution?

And answer to the second question is yes - see the first line.

To complete this topic. I measured the performance of 3 methods: dot style, XPath on the file and XPath on the node. There is no significant differece between them. Here are the details.

I parsed 2 times 2 files 60MB each.

1. Object style (dot style)

   ...
   $StartTime = Get-Date
   foreach ($file in $files) {
       [xml]$xml = Get-Content $file
   
       #Object style
       $product = $xml.catalog.product | Where-Object {$_."product-id" -eq "50610"}
       $of = $product."online-flag"
       $glblsid = $of | Where-Object {$_ -is [System.String]}
       $specsid = ($of | Where-Object {$_."site-id" -eq "ru"})."#text"
       Write-Output "$($file.Name) $glblsid $specsid"
   }
   $EndTime = Get-Date
   $TimeSpan = New-TimeSpan -Start $StartTime -End $EndTime
   Write-Output $TimeSpan.TotalMilliseconds
   

   Results:

   PS> .\ParseXML2.ps1
   2017-08-10_190159.xml false false
   2017-08-11_190203.xml false true
   36269,535
   PS> .\ParseXML2.ps1
   2017-08-10_190159.xml false false
   2017-08-11_190203.xml false true
   36628,3304
   

2. XPath on the file:

   ...
   $StartTime = Get-Date
   foreach ($file in $files) {
       [xml]$xml = Get-Content $file
   
       #XPath on the file
       $namespace = $xml.DocumentElement.NamespaceURI
       $ns = New-Object System.Xml.XmlNamespaceManager($xml.NameTable)
       $ns.AddNamespace("ns", $namespace)
       $glblsid = $xml.SelectSingleNode("/ns:catalog/ns:product[@product-id='50610']/ns:online-flag[not(@site-id)]", $ns).'#text'
       $specsid = $xml.SelectSingleNode("/ns:catalog/ns:product[@product-id='50610']/ns:online-flag[@site-id='ru']", $ns).'#text'
       Write-Output "$($file.Name) $glblsid $specsid"
   }
   $EndTime = Get-Date
   $TimeSpan = New-TimeSpan -Start $StartTime -End $EndTime
   Write-Output $TimeSpan.TotalMilliseconds
   

   Results:

   PS> .\ParseXML2.ps1
   2017-08-10_190159.xml false false
   2017-08-11_190203.xml false true
   36129,1368
   PS> .\ParseXML2.ps1
   2017-08-10_190159.xml false false
   2017-08-11_190203.xml false true
   38890,3014
   

3. XPath on the node:

   ...
   $StartTime = Get-Date
   foreach ($file in $files) {
       [xml]$xml = Get-Content $file
   
       #XPath on the node
       $namespace = $xml.DocumentElement.NamespaceURI
       $ns = New-Object System.Xml.XmlNamespaceManager($xml.NameTable)
       $ns.AddNamespace("ns", $namespace)
       $product = $xml.SelectSingleNode("/ns:catalog/ns:product[@product-id='50610']", $ns)
       $glblsid = $product.SelectSingleNode("ns:online-flag[not(@site-id)]", $ns).'#text'
       $specsid = $product.SelectSingleNode("ns:online-flag[@site-id='ru']", $ns).'#text'
       Write-Output "$($file.Name) $glblsid $specsid"
   }
   $EndTime = Get-Date
   $TimeSpan = New-TimeSpan -Start $StartTime -End $EndTime
   Write-Output $TimeSpan.TotalMilliseconds
   

   Results:

   PS> .\ParseXML2.ps1
   2017-08-10_190159.xml false false
   2017-08-11_190203.xml false true
   33477,1708
   PS> .\ParseXML2.ps1
   2017-08-10_190159.xml false false
   2017-08-11_190203.xml false true
   34116,7626