Adding Additional Commands - Extracted Unattend Schema XSD

[dmidlo]

Hey I've just begun working on some automation, and I'll be working with UnattendXmlBuilder during the course of the project. I imagine and hope I'll run into some opportunities to contribute. One thing I've found so far is that it is incredibly hard to find an XSD for unattend to perform validation against. Scouring the web, I was able to find this article by @cschneegans who has built an extensive online unattend generator.

I thought I'd try to write something native to PS to retrieve the XSD in a repeatable fashion, here's the two functions I've come up with. Hope it helps someday!

function Get-ComponentPlatformSchemaString {
    # Specify the path to the target DLL
    $dllPath = "C:\Program Files (x86)\Windows Kits\10\Assessment and Deployment Kit\Deployment Tools\WSIM\amd64\microsoft.componentstudio.componentplatforminterface.dll"

    # Load the assembly
    try {
        $assembly = [Reflection.Assembly]::LoadFrom($dllPath)
        Write-Host "Loaded assembly: $($assembly.FullName)"
    } catch {
        Write-Host "Failed to load assembly: $dllPath `n`n`n"
        return
    }

    # Get the names of embedded resources
    $resourceNames = $assembly.GetManifestResourceNames()

    if (-not $resourceNames.Count -eq 0) {

        $resourceNames | ForEach-Object {

            # Extract and display the contents of XML resources
            if ($_.EndsWith(".resources")) {
                try {
                    $stream = $assembly.GetManifestResourceStream($_)
                    if ($stream) {
                        $reader = New-Object System.IO.StreamReader($stream)
                        $content = $reader.ReadToEnd()
                        $reader.Close()
                        $stream.Close()

                        # Check for XML content within the resource
                        if ($content -match "<\?xml version=""1.0"" encoding=""ASCII""\?>") {
                            Write-Host "XML content found in resource $($_)"
                            return $content
                        }
                    }
                } catch {}
            }
        }
    }
}

function Get-UnattendSchema {
    $schemaResouceDump = Get-ComponentPlatformSchemaString

    $lines = $schemaResouceDump -split "`r?`n"

    $schemaStartIndex = $null
    $schemaEndIndex = $null

    for ($index = 0; $index -lt $lines.Count; $index++) {
        $line = $lines[$index]
    
        if ($line -like "*<xsd:schema*") {
            $schemaStartIndex = $index
        }
    
        if ($line -like "*</xsd:schema>*") {
            $schemaEndIndex = $index
            break
        }
    }

    if ($schemaStartIndex -eq $null -or $schemaEndIndex -eq $null) {
        Write-Warning "Schema start or end tag not found."
    }
    
    $unattendSchema = ($lines[$schemaStartIndex..$schemaEndIndex] -join "`n")
    $unattendSchema | Out-File -FilePath "$($PWD.Path)\unattend.xsd"

    return $unattendSchema
}

And the returned schema:

<xsd:schema targetNamespace="urn:schemas-microsoft-com:unattend" xmlns="urn:schemas-microsoft-com:unattend"
            xmlns:xsd="http://www.w3.org/2001/XMLSchema"
            elementFormDefault="qualified" attributeFormDefault="unqualified">

    <!--Root Elements-->
    <xsd:element name="unattend">
        <xsd:annotation>
            <xsd:documentation>Unattend</xsd:documentation>
        </xsd:annotation>
        <xsd:complexType>
            <xsd:complexContent>
                <xsd:extension base="unattendType" />
            </xsd:complexContent>
        </xsd:complexType>
    </xsd:element>

    <xsd:complexType name="unattendType">
       <xsd:sequence>
          <xsd:element name="servicing" type="servicingType" minOccurs="0" maxOccurs="1"/>
          <xsd:element name="settings" type="settingType" minOccurs="0" maxOccurs="unbounded"/>
          <xsd:any namespace="##other" processContents="lax" minOccurs="0" maxOccurs="unbounded"/>
       </xsd:sequence>
       <xsd:attribute name="author" type="xsd:string" use="optional"/>
       <xsd:attribute name="description" type="xsd:string" use="optional"/>
       <xsd:attribute name="creationTimeStamp" type="xsd:dateTime" use="optional"/>
       <xsd:attribute name="lastUpdateTimeStamp" type="xsd:dateTime" use="optional"/>
       <xsd:attribute name="ConfigurationSetTimeStamp" type="xsd:dateTime" use="optional"/>
       <xsd:anyAttribute namespace="##other" processContents="lax"/>
    </xsd:complexType>

      <xsd:complexType name="servicingType">
         <xsd:sequence>
            <xsd:element name="package" type="packageType" minOccurs="0" maxOccurs="unbounded"/>
         </xsd:sequence>
      </xsd:complexType>

   <xsd:complexType name="settingType">
       <xsd:sequence>
        <xsd:element name="component" type="componentSettingType" minOccurs="0" maxOccurs="unbounded"/>
       </xsd:sequence>
       <xsd:attribute name="pass" type="passType" use="required"/>
   </xsd:complexType>

   <xsd:complexType name="componentSettingType">
       <xsd:sequence>
          <xsd:any namespace="##any" processContents="lax" minOccurs="0" maxOccurs="unbounded"/>
       </xsd:sequence>
      <xsd:attribute name="name" type="xsd:string" use="required"/>
      <xsd:attribute name="version" type="fourPartVersionType" use="optional"/>
      <xsd:attribute name="processorArchitecture" type="processorArchitectureType" use="required"/>
      <xsd:attribute name="publicKeyToken" type="publicKeyTokenType" use="required"/>
      <xsd:attribute name="language" type="xsd:string" use="required"/>
      <xsd:attribute name="versionScope" type="versionScopeType" use="optional" default="nonSxS"/>
   </xsd:complexType>

   <xsd:simpleType name="passType">
      <xsd:annotation>
         <xsd:documentation>Installation phase to perform setting</xsd:documentation>
      </xsd:annotation>
         <xsd:restriction base="xsd:string">
         <xsd:enumeration value="offlineServicing"/>
         <xsd:enumeration value="windowsPE"/>
         <xsd:enumeration value="generalize"/>
         <xsd:enumeration value="specialize"/>
         <xsd:enumeration value="auditSystem"/>
         <xsd:enumeration value="auditUser"/>
         <xsd:enumeration value="oobeSystem"/>
         <xsd:enumeration value="oobeUser"/>
      </xsd:restriction>
   </xsd:simpleType>

   <xsd:complexType name="packageType">
      <xsd:sequence>
         <xsd:element name="assemblyIdentity" type="identityType" />
         <xsd:choice minOccurs="0" maxOccurs="unbounded">
           <xsd:element name="source" type="sourceType"/>
           <xsd:element name="selection" type="selectionType"/>
         </xsd:choice>
      </xsd:sequence>
      <xsd:attribute name="action" type="actionType" use="required"/>
      <xsd:attribute name="permanence" type="permanenceType" use="optional" default="removable"/>
      <xsd:anyAttribute namespace="##other" processContents="lax"/>
   </xsd:complexType>

   <xsd:complexType name="sourceType">
      <xsd:annotation>
         <xsd:documentation>Package source specification.</xsd:documentation>
      </xsd:annotation>
      <xsd:attribute name="location" type="xsd:string" use="required">
         <xsd:annotation>
            <xsd:documentation>Path to source location for package to install.</xsd:documentation>
         </xsd:annotation>
      </xsd:attribute>
      <xsd:attribute name="permanence" type="permanenceType" use="optional" default="permanent"/>
   </xsd:complexType>

   <xsd:complexType name="selectionType">
      <xsd:annotation>
         <xsd:documentation>Selection state override for nested child packages.</xsd:documentation>
      </xsd:annotation>
      <xsd:attribute name="name" type="xsd:string" use="required">
         <xsd:annotation>
            <xsd:documentation>Name of selectable update within child package.</xsd:documentation>
         </xsd:annotation>
      </xsd:attribute>
      <xsd:attribute name="state" type="xsd:boolean" use="required">
         <xsd:annotation>
            <xsd:documentation>Boolean initial state for selection.</xsd:documentation>
         </xsd:annotation>
      </xsd:attribute>
   </xsd:complexType>

   <xsd:simpleType name="actionType">
      <xsd:annotation>
         <xsd:documentation>Installation action to perform on package.</xsd:documentation>
      </xsd:annotation>
         <xsd:restriction base="xsd:string">
         <xsd:enumeration value="remove"/>      <!-- remove package from system -->
         <xsd:enumeration value="stage"/>       <!-- fully stage package, ready for installation -->
         <xsd:enumeration value="install"/>     <!-- install package on system, then configure -->
         <xsd:enumeration value="configure"/>   <!-- configure currently installed package -->
      </xsd:restriction>
   </xsd:simpleType>

   <xsd:simpleType name="permanenceType">
      <xsd:annotation>
         <xsd:documentation>Uninstall options.</xsd:documentation>
      </xsd:annotation>
      <xsd:restriction base="xsd:string">
         <xsd:enumeration value="removable"/>   <!-- normal uninstall behavior -->
         <xsd:enumeration value="permanent"/>   <!-- cannot be removed -->
         <xsd:enumeration value="temporary"/>   <!-- removed when any component updated -->
      </xsd:restriction>
   </xsd:simpleType>

   <xsd:complexType name="identityType">
      <xsd:attribute name="name" type="xsd:string" use="required"/>
      <xsd:attribute name="version" type="fourPartVersionType" use="required"/>
      <xsd:attribute name="processorArchitecture" type="processorArchitectureType" use="required"/>
      <xsd:attribute name="publicKeyToken" type="publicKeyTokenType" use="required"/>
      <xsd:attribute name="language" type="xsd:string" use="required"/>
      <xsd:attribute name="versionScope" type="xsd:string" use="optional" fixed="nonSxS"/>
   </xsd:complexType>

   <xsd:simpleType name="versionScopeType">
      <xsd:restriction base="xsd:string">
         <xsd:pattern value="((N|n)(E|e)(U|u)(T|t)(R|r)(A|a)(L|l))|((N|n)(O|o)(N|n)(S|s)(X|x)(S|s))"/>
      </xsd:restriction>
   </xsd:simpleType>

   <xsd:simpleType name="fourPartVersionType">
      <xsd:restriction base="xsd:string">
         <xsd:pattern value="(0*[0-9]{0,4}|0*[1-5][0-9]{4}|0*6[0-4][0-9]{3}|0*65[0-4][0-9]{2}|0*655[0-2][0-9]|0*6553[0-5])\.(0*[0-9]{0,4}|0*[1-5][0-9]{4}|0*6[0-4][0-9]{3}|0*65[0-4][0-9]{2}|0*655[0-2][0-9]|0*6553[0-5])\.(0*[0-9]{0,4}|0*[1-5][0-9]{4}|0*6[0-4][0-9]{3}|0*65[0-4][0-9]{2}|0*655[0-2][0-9]|0*6553[0-5])\.(0*[0-9]{0,4}|0*[1-5][0-9]{4}|0*6[0-4][0-9]{3}|0*65[0-4][0-9]{2}|0*655[0-2][0-9]|0*6553[0-5])$"/>
      </xsd:restriction>
   </xsd:simpleType>

   <xsd:simpleType name="publicKeyTokenType">
      <xsd:restriction base="xsd:string">
         <xsd:pattern value="([0-9]|[a-f]|[A-F]){16}"/>
      </xsd:restriction>
   </xsd:simpleType>

   <xsd:simpleType name="processorArchitectureType">
      <xsd:restriction base="xsd:string">
         <xsd:pattern value="^(((X|x)86)|((I|i)(A|a)64)|((A|a)(M|m)(D|d)64)|((W|w)(O|o)(W|w)64)|((M|m)(S|s)(I|i)(L|l))|((S|s)(H|h)(X|x))|((A|a)(R|r)(M|m)(64)?)|((D|d)(A|a)(T|t)(A|a))|((N|n)(E|e)(U|u)(T|t)(R|r)(A|a)(L|l)))$"/>
      </xsd:restriction>
   </xsd:simpleType>

</xsd:schema>

[MartinGC94]

Very cool trick, but looking at the schema it doesn't look like there's any need to dynamically retrieve it because it doesn't have any references to individual components. Therefore, if I were to add a Test-UnattendFile command I'd probably just manually extract the schema once and bundle it with the module instead of adding a dependency on having WSIM installed.

[dmidlo]

yeah, that's a portion of what I'm working on. ...A complete schema 💯

This took way too long but here's an updated validator function.

I'm trying to get some more chops with PRs and Git, any chance you'd review a PR on the validator to ./Functions/Public to get started?

[MartinGC94]

Sure. Here's my quick thoughts on the implementation:

1. You place this generic Test-Xml function in the private folder so it doesn't get exported.
2. You create a new Test-UnattendFile public function which calls Test-Xml with the correct parameters to validate an unattend file. If you need the schema for this you can either add it as a here-string inside the function, or just place the file in the root of the module and reference that.
3. Test-UnattendFile should by default only return true/false and it should not write to the error stream unless there's a parameter validation error (eg. file doesn't exist or whatever).
4. You are welcome to add a -Detailed switch which outputs a more detailed object if you think that makes sense. If the switch is set you are also allowed to write errors to the error stream.
5. Please use the correct data streams. I see you write warnings and errors to the verbose stream and that seems wrong.

And here's my thoughts on styling:

1. I use the Allman brace style: https://en.wikipedia.org/wiki/Indentation_style#Allman_style
2. Don't escape newlines with backticks, instead use the natural line continuation features in PowerShell.
3. For attributes with a bool property you don't need to explicitly specify $true, you can do it like this: [Parameter(Mandatory, ValueFromPipeline)]
4. Don't use Throw as that causes script terminating error. Use $PSCmdlet.ThrowTerminatingError() instead which is a statement terminating error.
5. I prefer ! over -not.
6. Use $null = instead of | Out-Null to silence output