Using hashtables to combine values

For a job I needed a good way of combining a primary value with optional subvalues in a xml-file.
Below is an example of how to extract attributes from a xmlelement into a hashtable and then join two hashtables into one. I couldn't find a method for extracting elements on the web, folks usually goes with subnodes instead of attributes. I'm partial to attributes and had to get creative, but the solution was quite simple. The Attributes from the element only show the actual elements from the xmlfile. Its not obvious when browsing the object that -name property can be lifted, but here it's used for creating a new hashtable-row



Samplescript for proof of concept

	$ScriptPath = $(split-path -Parent $myinvocation.MyCommand.Definition)
	Import-Module "$($ScriptPath)\Tools.psm1" -force
	[xml]$xml = get-content -path "$($scriptPath)\websiteNodes.xml"
	$nodes = $xml.SelectNodes("//webSites/webSite")
	$collection = @()
	foreach ($node in $nodes) {
	$propertyDefault = @{url="test";name="test2";else="else"}
	$propertyTemp = convert-xmlAttribToHash -xmlElement $node
	$newProperty = Join-Hashtable -master $propertyTemp -child $propertyDefault
	$object = new-object PSObject -Property $newProperty
	$collection += $object
	}
	$collection[0]

view raw setProperties.ps1 hosted with ❤ by GitHub

	Function Join-Hashtable {
	[cmdletbinding()]
	Param (
	[hashtable]$Master,
	[hashtable]$Child
	)
	#create clones of hashtables so originals are not modified
	$Primary = $master.Clone()
	$Secondary = $child.Clone()
	#check for any duplicate keys
	$duplicates = $Primary.keys | where {$Secondary.ContainsKey($_)}
	if ($duplicates) {
	foreach ($item in $duplicates) {
	$Secondary.Remove($item)
	}
	}
	#join the two hash tables
	$result = $Primary+$Secondary
	return $result
	} #end Join-Hashtable
	function convert-xmlAttribToHash {
	param(
	$xmlElement
	)
	$hashTable = @{}
	foreach ($attrib in $xmlElement.Attributes) {
	$hashTable.$($attrib.name) = $attrib.value
	}
	return $hashTable
	}

view raw Tools.psm1 hosted with ❤ by GitHub

	<webSites rootUrl="https://portal.mycompany.com/subsites/mastersite" defaultLanguage="1053" useParentTopNav="true" defaultTemplate="STS#0">
	<webSite name="MerSupport" url="/support/mersupport" language="1033" />
	<webSite name="Support" url="/support" language="1033" />
	<webSite name="Support3" url="/support3" />
	</webSites>

view raw websiteNodes.xml hosted with ❤ by GitHub

This eventually led to createwebsFromStructure.ps1 that uses powershell splatting to build commands with the resulting hashtable.

	Add-PSSnapin microsoft.sharepoint.powershell
	$scriptPath = $(split-path -Parent $MyInvocation.MyCommand.Definition)
	Import-Module "$($scriptPath)\Tools.psm1"
	$xmlStructureName = "webSiteNodes.xml"
	$xmlStructurePath = Join-Path -Path $scriptPath -ChildPath $xmlStructureName
	[xml]$xmlStructure = Get-Content -Path $xmlStructurePath
	$root = $xmlStructure.SelectSingleNode("//webSites")
	$rootUrl = $xmlStructure.webSites.rootUrl
	$allWebSites = $xmlStructure.SelectNodes("//webSites/webSite")
	#sort for order of handling first
	foreach ($allWebSite in $allWebSites) {
	$depth = $($allWebSite.url.Split("/").count)-1
	$allWebSite |Add-Member -MemberType NoteProperty "UrlDepth" -Value $depth -Force
	}
	$rootProperty = @{language=$root.defaultLanguage;useParentTopNav=$root.useParentTopNav;Template=$root.defaultTemplate}
	#create websites
	foreach ($website in ($allWebSites|sort-object urldepth)) {
	$fullUrl = "$($rootUrl)$($website.url)"
	$checkExists = get-spweb $fullUrl -ErrorAction SilentlyContinue
	if ($checkExists -eq $null) {
	write-output "Creating site at $fullUrl"
	#join parameters with defaults
	$propertyTemp = @{}
	foreach ($attrib in $website.Attributes) {
	$propertyTemp.$($attrib.name) = $attrib.value
	}
	$propertyTemp.url = $propertyTemp.url.Insert(0,$rootUrl)
	$newProperty = Join-Hashtable -master $propertyTemp -Child $rootProperty
	if ($newProperty.useParentTopNav -eq 'true') {
	write-output "Using topparentnav"
	$newProperty.remove('UseParentTopNav')
	New-SPWeb @newProperty -UseParentTopNav
	}
	else {
	write-output "Not using topparentNav"
	$newProperty.remove('UseParentTopNav')
	New-SPWeb @newProperty
	}
	}
	else { write-output "Site already exists. Skipping creation..." }
	}

view raw createWebsFromStructure.ps1 hosted with ❤ by GitHub

References:
https://powershell.org/2013/01/23/join-powershell-hash-tables/ - source for join-hashtable function
https://technet.microsoft.com/en-us/library/gg675931.aspx - source for details on splatting