Identifying and Removing Unknown Renderings

In the dynamic world of Sitecore development, maintaining data integrity is crucial to deliver a seamless and engaging user experience. One common challenge that developers face is ensuring that the Item IDs referenced within the content tree are valid and exist in the Sitecore instance. Failing to address this issue can lead to broken links, rendering errors, and an overall degraded user experience. In this blog post, we’ll explore a practical approach using PowerShell Extensions (SPE) to verify Renderings and safeguard against the presence of “Unknown Renderings.”

Content authors often create and manage numerous renderings, which are components responsible for displaying content on web pages. However, over time, some renderings might become obsolete or be unintentionally deleted, leaving behind “Unknown Renderings” in the layout definitions. These “Unknown Renderings” reference Item IDs that no longer exist within the Sitecore instance, leading to broken functionality and inconsistent rendering on web pages.

By using SPE we can address the challenge of “Unknown Renderings” and ensure the validity of referenced Item IDs. The script we’ll discuss helps identify and remove any “Unknown Renderings” from the layout definitions, improving the data integrity of your Sitecore implementation.

The PowerShell script utilizes the Get-Item command from SPE to retrieve the target item. It then examines the layout definition and iterates through the renderings associated with the item. For each rendering, the script verifies the existence of the referenced Item ID within Sitecore. If an “Unknown Rendering” is detected, it is removed from the layout definition, preventing broken links and ensuring a consistent rendering experience for end-users.

$itemPath = "<your-path>"
$item = Get-Item -Path $itemPath

#Shared or Final Layout?
$sharedLayout = $true

# Get the layout field
if($sharedLayout) {
    $layoutField = New-Object Sitecore.Data.Fields.LayoutField -ArgumentList $item.Fields[[Sitecore.FieldIDs]::LayoutField]
} else {
    $layoutField = New-Object Sitecore.Data.Fields.LayoutField -ArgumentList $item.Fields[[Sitecore.FieldIDs]::FinalLayoutField]
}

# Parse the layout definition
$layoutDefinition = [Sitecore.Layouts.LayoutDefinition]::Parse($layoutField.Value)

# Get the device definition (in that case the Default)
$ddef = $layoutDefinition.GetDevice("{FE5D7FDF-89C0-4D99-9AA3-B5FBD009C9F3}")

# Get the array of all renderings for the target page item
$renderingsArray = $ddef.Renderings | ForEach-Object { [Sitecore.Layouts.RenderingDefinition]$_ }

# Create lists to manipulate the Rendering list
$originalRenderingsList = [System.Collections.Generic.List[Sitecore.Layouts.RenderingDefinition]]($renderingsArray)
$newRenderingsList = [System.Collections.Generic.List[Sitecore.Layouts.RenderingDefinition]]($renderingsArray)

#For each rendering, checks if the item exist ()
$originalRenderingsList | Where { 
    $renderingItem = Get-Item -Path "master:" -ID $_.ItemId -ErrorAction SilentlyContinue
    
    if(!$renderingItem) {
        Write-Host $_.ItemId - "Unknown Rendering Found"
        $newRenderingsList.Remove($_)
    } 
}

# Update the renderings array in the device definition
$ddef.Renderings = $newRenderingsList.ToArray()

# Save the layout changes
$item.Editing.BeginEdit()
$layoutField.Value = $layoutDefinition.ToXml()
$item.Editing.EndEdit()

I’ll explain the purpose of each step along the way:

if($sharedLayout) {
    $layoutField = New-Object Sitecore.Data.Fields.LayoutField -ArgumentList $item.Fields[[Sitecore.FieldIDs]::LayoutField]
} else {
    $layoutField = New-Object Sitecore.Data.Fields.LayoutField -ArgumentList $item.Fields[[Sitecore.FieldIDs]::FinalLayoutField]
}

In this line, we create a new instance of the LayoutField class, which represents the layout field of the target item. We use the LayoutField constructor and pass in the layout field from the item using $item.Fields[[Sitecore.FieldIDs]::LayoutField] for Shared Layout or $item.Fields[[Sitecore.FieldIDs]::FinalLayoutField] for Final Layout.

# Get the device definition (in this case, the Default)
$ddef = $layoutDefinition.GetDevice("{FE5D7FDF-89C0-4D99-9AA3-B5FBD009C9F3}")

Here, we obtain the device definition object.

# Get the array of all renderings for the target page item
$renderingsArray = $ddef.Renderings | ForEach-Object { [Sitecore.Layouts.RenderingDefinition]$_ }

Then, we retrieve all the renderings defined in the layout for the target page item. We access the Renderings property of the device definition, which returns a collection of rendering items. In this line, we use the ForEach-Object cmdlet to iterate through each rendering and cast it as a RenderingDefinition object using the [Sitecore.Layouts.RenderingDefinition]$_ syntax. This step ensures that we have a strongly-typed collection of rendering definitions to work with.

# Create lists to manipulate the Rendering list
$originalRenderingsList = [System.Collections.Generic.List[Sitecore.Layouts.RenderingDefinition]]($renderingsArray)
$newRenderingsList = [System.Collections.Generic.List[Sitecore.Layouts.RenderingDefinition]]($renderingsArray)

Create lists to properly manipulate the renderings deleted.

#For each rendering, checks if the item exist ()
$originalRenderingsList | Where { 
    $renderingItem = Get-Item -Path "master:" -ID $_.ItemId -ErrorAction SilentlyContinue
    
    if(!$renderingItem) {
        Write-Host $_.ItemId - "Unknown Rendering Found"
        $newRenderingsList.Remove($_)
    } 
}

Check each rendering ID, if it isn’t found, it’s removed from the renderings list

# Update the renderings array in the device definition
$ddef.Renderings = $newRenderingsList.ToArray()

Update the page’s renderings object.

# Save the layout changes
$item.Editing.BeginEdit()
$layoutField.Value = $layoutDefinition.ToXml()
$item.Editing.EndEdit()

And finally, updates the item with the new list of renderings.

By following these steps, we can access and manipulate the layout structure of an item in Sitecore, specifically focusing on the renderings associated with it.

To implement this script, you need to install the Sitecore PowerShell Extensions module in your Sitecore instance. Once installed, you can customize the script to fit your specific needs, such as adjusting the item path, rendering IDs to exclude, or expanding it to validate other fields or scenarios within Sitecore. Tailoring the script to your requirements enhances the overall data integrity of your Sitecore environment.

Alright,

Maintaining data integrity is crucial for a robust Sitecore implementation. By utilizing PowerShell and the Sitecore PowerShell Extensions module, we can automate the verification of Item IDs and address the issue of “Unknown Renderings”. Identifying and removing these “Unknown Renderings” ensures a reliable and consistent rendering experience, minimizing the risk of broken links and enhancing the overall user experience.

Thanks!