SPE: Compare Content Branches

# Site 1 content path
$site1 = "/sitecore/content/Sites/Site1"
# Site 2 content path
$site2 = "/sitecore/content/Sites/Site2"
# Get site relative paths and IDs
$site1Desc = Get-ChildItem  -Path "master:$site1" -Recurse
# Flat lookup for quick ID grabbing
$site1Lookup = $site1Desc | ForEach-Object { $lookup = @{} } { $lookup[$_.FullPath.Replace($site1, "")] = $_.ID } { $lookup }
# Array of objects to compare directly, would normally use the list of descendands, but we needed to trim path to be relative.
$site1LookupRel = $site1Desc | ForEach-Object { $objArr = @() } { 
       $newObj = (New-Object -TypeName PSObject | Add-Member NoteProperty Name $_.Name -PassThru | Add-Member NoteProperty ID $_.ID -PassThru | Add-Member NoteProperty Path $_.FullPath.Replace($site1, "") -PassThru)
       $objArr += $newObj
} { $objArr }

#same stuff, different Site
$site2Desc = Get-ChildItem  -Path "master:$site2" -Recurse
$site2Lookup = $site2Desc | ForEach-Object { $lookup = @{} } { $lookup[$_.FullPath.Replace($site2, "")] = $_.ID } { $lookup }
$site2LookupRel = $site2Desc | ForEach-Object { $objArr = @() } { 
        $newObj = (New-Object -TypeName PSObject | Add-Member NoteProperty Name $_.Name -PassThru | Add-Member NoteProperty ID $_.ID -PassThru | Add-Member NoteProperty Path $_.FullPath.Replace($site2, "") -PassThru)
        $objArr += $newObj
    } { $objArr }
      
# Compare lists of relative paths/items
$itemComparison = Compare-Object -ReferenceObject $site1LookupRel -DifferenceObject $site2LookupRel -Property Path -IncludeEqual
# Use SideIndicator to grab those that match
$matchingItems = $itemComparison | Where-Object { $_.SideIndicator -eq "==" } |Select-Object -Expand Path
# Use SideIndicator to grab those that don't match
$nonMatchingItems = $itemComparison | Where-Object { $_.SideIndicator -ne "==" } |Select-Object -Expand Path
Write-Host " *** Matching Items *** "
foreach($matchingItem in $matchingItems) {
    $site1MatchingItem = $null;
    $site2MatchingItem = $null;
    # Quick check to make sure the do exist in both
    if($site1Lookup.Contains($matchingItem))
    {
        $site1MatchingItem = Get-Item -Path "master:" -ID $site1Lookup[$matchingItem]
    }
        
    if($site2Lookup.Contains($matchingItem)){
        $site2MatchingItem = Get-Item -Path "master:" -ID $site2Lookup[$matchingItem]
    }
    
    # If both exist, get all fields that are not using a Standard Value
    if($site1MatchingItem -ne $null -AND $site2MatchingItem -ne $null) {
       $site1ItemFieldValues = Get-ItemField -Item $site1MatchingItem -ReturnType Field -Name "*" | Where-Object {!$_.ContainsStandardValue}  | Select-Object -Property @{Name="SourceID"; Expression={$site1MatchingItem.ID}},Name,Value 
       $site2ItemFieldValues = Get-ItemField -Item $site2MatchingItem -ReturnType Field -Name "*"  | Where-Object {!$_.ContainsStandardValue} | Select-Object -Property @{Name="SourceID"; Expression={$site2MatchingItem.ID}},Name,Value 
       # If there are fields to compare, let's compare!
       if($site1ItemFieldValues -ne $null -AND $site2ItemFieldValues -ne $null){
           Write-Host "$matchingItem does exist in both sites, comparing now - (" $site1MatchingItem.ContentPath " <=>" $site2MatchingItem.ContentPath ")" -ForegroundColor Green
	   $comparedItems = Compare-Object -ReferenceObject $site1ItemFieldValues -DifferenceObject $site2ItemFieldValues -Property Name,Value -IncludeEqual -PassThru
	   $comparedItems | Format-Table -AutoSize
       }
       # There might not be any fields to compare (ie a _content folder that has no custom fields)
       else{
           Write-Host "$matchingItem does exist in both sites, but there is nothing to compare - (" $site1MatchingItem.ContentPath " <=>" $site2MatchingItem.ContentPath ")" -ForegroundColor Green
       }
    }
}
Write-Host " *** NonMatching Items *** "
foreach($nonMatchingItem in $nonMatchingItems) {
    $site1MatchingItem = $null;
    $site2MatchingItem = $null;
    # Ok, found a mismatch, let's see which Site has what
    if($site1Lookup.Contains($nonMatchingItem))
    {
        $site1MatchingItem = Get-Item -Path "master:" -ID $site1Lookup[$nonMatchingItem]
    }
    
    if($site2Lookup.Contains($nonMatchingItem)){
        $site2MatchingItem = Get-Item -Path "master:" -ID $site2Lookup[$nonMatchingItem]
    }
        
    if($site1MatchingItem -ne $null -AND $site2MatchingItem -eq $null){
        Write-Host "$nonMatchingItem exists in Site1 but not Site2 - (" $site1MatchingItem.ContentPath ")" -ForegroundColor Yellow
    }
    elseif($site1MatchingItem -eq $null -AND $site2MatchingItem -ne $null){
        Write-Host "$nonMatchingItem exists in Site2 but not Site1 - (" $site2MatchingItem.ContentPath ")" -ForegroundColor Yellow
    }
}