Retrieves IIS settings from remote machines and presents difference view in winmerge

Compare-iisSites.ps1

#Requires -Modules webadministration
#Requires -RunAsAdministrator 
#Requires -version 3.0
<#
	.SYNOPSIS
		Provides a means to get the current backup location for iis changes
	
	.DESCRIPTION
		Changes made to the IIS instance are recorded in a history config file.  This function provides the means to retreive where it is on the machine
		
		Get-IISSystemHistoryLocation -index '2' 
	
	.PARAMETER index
		if a value for index is passed it'll get the x number from the collection of history backups.
		For instance if there are 5 backups and the index number passed is 2 then It'll get the next backup from the latest.
	
	.Example
        PS PS:\> Get-IISSystemHistoryLocation -computerName test 0
        \\test\C$\inetpub\history\CFGHISTORY_0000000033
    .Example 2
        PS PS:\> Get-IISSystemHistoryLocation -computerName test 3
        \\test\C$\inetpub\history\CFGHISTORY_0000000030
#>
function Get-IISSystemHistoryLocation
{
	[OutputType([string])]
	param
	(
        [string]$computerName,
		[Parameter(Mandatory = $false)]
		[int16]$index = '1'
	)
    $computerName = Get-LocalRemoteComputer -computername $computerName
	if($computerName -ne $env:COMPUTERNAME)
    {
		$startingdir = Resolve-EnvVariable -String '%systemroot%' -computername $computername
    }
    else
    {
        $startingdir = $env:windir
    }
	$config = [xml](get-content "$startingDir\system32\inetsrv\config\schema\IIS_schema.xml")
	$configHistory = (($config.configSchema.sectionschema | where{ $_.name -like "*configHistory*" }).attribute | ?{ $_.name -like "path" }).defaultvalue
	$envVar = $configHistory | Resolve-EnvVariable -computername $computername
	$configDir = dir $envVar | Sort-Object -Property lastwritetime -Descending | select -Index $index
	$configd = $configdir.fullname
    $configd -match '\w:' | out-null
    if($Matches)
    {
        $driveLetter = ($Matches.values).trim(':') 
        $serverConfig = $configd  -replace '\w:', "\\$computername\$driveletter$"
        $configd = $serverConfig
    }
    $configd
}
<#
	.SYNOPSIS
		A brief description of the Resolve-EnvVariable function.
	
	.DESCRIPTION
		Takes an environment variable and resolves it to the actual location stripping off the %% from a dos command.
		
		example
		Resolve-EnvVariable -String %temp% -computername $computername
		\\servername\C$\Users\TSCHUM~1\AppData\Local\Temp
		Resolve-EnvVariable -String %temp% -computername .
		C:\Users\TSCHUM~1\AppData\Local\Temp

	.PARAMETER String
		Enter a string that contains an environmental variable like %WINDIR%
	
	.PARAMETER computername
		Name of the computer to check the environment variable against.

#>
function Resolve-EnvVariable
{
	[CmdletBinding()]
	param
	(
		[Parameter(Mandatory = $true,
				   ValueFromPipeline = $true,
				   Position = 0,
				   HelpMessage = 'Enter a string that contains an environmental variable like %WINDIR%')]
		[ValidateNotNullOrEmpty()]
		[string]$String,
		[string]$computername
	)
	#https://powershell.org/friday-fun-expand-environmental-variables-in-powershell-strings/
	Begin
	{
		$computerName = Get-LocalRemoteComputer -computername $computerName
		Write-Verbose "Starting $($myinvocation.mycommand)"
		
	} #Begin
	
	Process
	{
		#if string contains a % then process it
		if ($string -match "%\S+%")
		{
			Write-Verbose "Resolving environmental variables in $String"
			#split string into an array of values
			$values = $string.split("%") | Where { $_ }
			foreach ($text in $values)
			{
				#find the corresponding value in ENV:
				Write-Verbose "Looking for $text"
				if ($env:COMPUTERNAME -ne $computername)
				{
					[string]$replace = (invoke-command -ComputerName $computername -ScriptBlock { param ([string]$t)get-item env:$t -ErrorAction SilentlyContinue } -ArgumentList $text).value
					#(Get-Item env:$text -erroraction "SilentlyContinue").Value
					if ($replace)
					{
						#if found append it to the new string
						Write-Verbose "Found $replace"
						$newstring += $replace
					}
					else
					{
						#otherwise append the original text
						$newstring += $text
					}
					$newstring -match '\w:' | out-null
					if ($Matches)
					{
						$driveLetter = ($Matches.values).trim(':')
						$newstring = $newstring -replace '\w:', "\\$computername\$driveletter$"
					}
					
				}
				else
				{
					[string]$replace = (Get-Item env:$text -erroraction "SilentlyContinue").Value
					if ($replace)
					{
						#if found append it to the new string
						Write-Verbose "Found $replace"
						$newstring += $replace
					}
					else
					{
						#otherwise append the original text
						$newstring += $text
					}
				}
				
			} #foreach value
			
			Write-Verbose "Writing revised string to the pipeline"
			#write the string back to the pipeline
			Write-Output $NewString
		} #if
		else
		{
			#skip the string and write it back to the pipeline
			Write-Output $String
		}
	} #Process
	
	End
	{
		Write-Verbose "Ending $($myinvocation.mycommand)"
	} #End
} #end Resolve-EnvVariable

<#
	.SYNOPSIS
		Gets the current backup location of IIS Configs
	
	.DESCRIPTION
		Gets the latest directory that contains the last IIS backup
		If you do not specify an index number then the function will get index 0 of the number of backups. 
		Each backup in IIS is a seperate directory the script determines how many there are and sets the first index number to the most recent backup.
	
	.PARAMETER computername
		 this is as string value that represents the comptutername that we want to find the backups for
	
	.PARAMETER index
		This is a integer(16) value that represents the index number of the backup you want to retrieve. the most recent backup is index 0. 
	
	.NOTES
		This returns a string object of the backup location for the computername passed.
    .Example
        PS PS:\> Get-LastIISBackupLocation -computername test 1
        returns: \\test\C$\Windows\system32\inetsrv\backup\2016-07-14
    .Example 2
        PS PS:\> Get-LastIISBackupLocation -computername test 0
        \\test\C$\Windows\system32\inetsrv\backup\2016-07-15
#>
function Get-LastIISBackupLocation
{
	[OutputType([string])]
	param
	(
		[string]$computername,
		[int16]$index = '0'
	)
	
	$computerName = Get-LocalRemoteComputer -computername $computerName
	if ($computerName -ne $env:COMPUTERNAME)
	{
		$startingdir = Resolve-EnvVariable -String '%systemroot%' -computername $computername
	}
	else
	{
		$startingdir = $env:windir
	}
	$mostRecentDir = dir ("$startingdir\system32\inetsrv\backup") | Sort-Object -Property Lastwritetime -Descending | select -Index $index
	$mostRecentDir.fullname
}
<#
	.SYNOPSIS
		Gets the current directory for the machine that is passed.
	
	.DESCRIPTION
		 Gets the current installed location of iis from the IIS 
	
	.PARAMETER computername
		string for computername that we want to find the current installation of iis
	
	.EXAMPLE
        Get-CurrentIISConfiguration -computername test
        returns: \\test\c$\windows\system32\inetsrv\config
#>
function Get-CurrentIIsConfiguration
{
	[OutputType([string])]
	param
	(
		[string]$computername
	)
	
	$computerName = Get-LocalRemoteComputer -computername $computerName
	if ($computerName -ne $env:COMPUTERNAME)
	{
		$startingdir = "\\$computername\c$\windows"
	}
	else
	{
		$startingdir = $env:windir
	}
	$mostRecentDir = "$startingdir\system32\inetsrv\config"
	$mostRecentDir
}

<#
	.SYNOPSIS
		Determines if the name passed is the localhost or not
	
	.DESCRIPTION
		If the name passed is the localhost then the script will send back the computername: 
		
		.example
		get-localremotecomputer -computername .
		yourmachinename
		get-localremotecomputer -computername 127.0.0.1
		yourmachinename
		get-localremotecomputer -computername servername
		servername
	
	.PARAMETER computername
		A description of the computername parameter.
	
	.NOTES
		Additional information about the function.
#>
function Get-LocalRemoteComputer
{
	param
	(
		[string]$computername
	)
	
	if ($computername -eq '.' -or ($env:COMPUTERNAME -eq $computername) -or ($computername -eq 'Localhost') -or ($computername -eq '127.0.0.1'))
	{
		$computername = $env:COMPUTERNAME
		$computername
	}
	else
	{ $computername }
}


<#
	.SYNOPSIS
		takes to files passed and sends them to winmerge for comparison
	
	.DESCRIPTION
		This function will pass the source and differnece file and then launch winmerge.
	
	.PARAMETER sourceFile
		file used to be the source of the comparison
	
	.PARAMETER diffFile
		file that is the difference file
	
	.PARAMETER winMergeLoc
		Physical location of the exe for winmerge. This function will pass the source and differnece file and then launch winmerge.
	
	.NOTES
		Additional information about the function.
#>
function Compare-IISConfigsWinMerge
{
	param
	(
		[string]$sourceFile,
		[string]$diffFile,
		[string]$winMergeLoc
	)
	
	if (test-path $winMergeLoc)
	{
		if (test-path $sourcefile)
		{
			if (test-path $difffile)
			{
				& "$winmergeLoc "  "$sourcefile " "$diffFile"
				$results = $true
			}
			else { $results = 'bad diff file' }
		}
		else {$results = 'bad source file'}
	}
	else {$results = 'bad winmerge location' }
	$results
}
$winmerge = '\\server\winmerge\WinMergePortable\winmergeportable.exe'
$history = Get-IISSystemHistoryLocation -computerName 'test' -index '2'
$current = Get-CurrentIIsConfiguration -computername 'test2'
Compare-IISConfigsWinMerge -winMergeLoc $winmerge -sourceFile "$current\applicationhost.config" -diffFile "$history\applicationHost.config"