PNP powershell SharePoint Online set modern page bannerimageurl - powershell

Question

My goal is to use PNP commandlets to set the SharePoint online modern bannerimageurl property for a page.
First I get a list of the pages and their current title and bannerimageurl values
# Get alist of all pages and their banner URLs
$items = Get-PnPListItem -List "SitePages" -Fields ID,Title,BannerImageUrl
$items | %{new-object PSObject -Property #{Id=$_["ID"];Title=$_["Title"];BannerImageUrl=$_["BannerImageUrl"].Url}} | select ID,Title,BannerImageUrl
But even if I then run the following code to set the BannerImage of one page (say ID2)
Set-PnPListItem -List "SitePages" -Id 2 -Values #{"BannerImageUrl" = " https://contoso.sharepoint.com/sites/mycomsite3/bannerimages/bread-braid-tedster-sml.jpg";}
When I run the following again the item 2 shows up as having a changed BannerImageUrl
$items = Get-PnPListItem -List "SitePages" -Fields ID,Title,BannerImageUrl
$items | %{new-object PSObject -Property #{Id=$_["ID"];Title=$_["Title"];BannerImageUrl=$_["BannerImageUrl"].Url}} | select ID,Title,BannerImageUrl
BUT when I actually view the page in the browser that is item 2 there has been no change to the banner image ??
Please tell me what I'm doing wrong when I set the BannerImageUrl.
Your experience and knowledge greatly accepted.

Answer 1

I've written a PS Function for that exact same problem based on the JS Solution here, in case you still need it:
function UpdateBannerImage {
param(
[string]$listName,
[int]$itemId,
[string]$newBannerUrl
)
#get list item
$item = Get-PnPListItem -List $listName -Id $itemId -Fields LayoutWebpartsContent, BannerImageUrl
if($item["LayoutWebpartsContent"] -match 'data-sp-controldata="([^"]+)"'){
# get substring w/ regex
$temp = $item["LayoutWebpartsContent"] | Select-String -Pattern 'data-sp-controldata="([^"]+)"'
$content = $temp.Matches.Groups[1].Value
# replace [] bc sometimes it throws later
$content = $content.replace("[","[").replace("]","]")
# decode
$dec = [System.Web.HttpUtility]::HtmlDecode($content)
# from JSON
$jnContent = ConvertFrom-Json $dec
#set values
if (!$jnContent.serverProcessedContent) {
$jnContent.serverProcessedContent = {};
}
if (!$jnContent.serverProcessedContent.imageSources) {
$jnContent.serverProcessedContent.imageSources = New-Object PSObject;
$jnContent.serverProcessedContent.imageSources | add-member Noteproperty imageSource $newBannerUrl
}
if(!$jnContent.serverProcessedContent.imageSources.imageSource){
$jnContent.serverProcessedContent.imageSources | add-member Noteproperty imageSource $newBannerUrl
}
$jnContent.serverProcessedContent.imageSources.imageSource = $newBannerUrl
# need to always create new properties, otherwise nothing changes
$curTitle = "";
if($jnContent.properties){
$curTitle = $jnContent.properties.title;
}
$jnContent.properties = New-Object PSObject;
$jnContent.properties | add-member Noteproperty title $curTitle
$jnContent.properties | add-member Noteproperty imageSourceType 2
# to JSON
$newContent = $jnContent | ConvertTo-Json -Compress
$enc = [System.Web.HttpUtility]::HtmlEncode($newContent)
$enc = $enc.replace("{","{").replace(":",":").replace("}","}").replace("[","[").replace("]","]")
# replace full item property
$fullContent = $item["LayoutWebpartsContent"].replace("[","[").replace("]","]");
$fullContent = $fullContent -replace $content, $enc
$fullContent.replace("[","[").replace("]","]")
# set & update
$item["LayoutWebpartsContent"] = $fullContent
$item.Update()
# not really sure if needed, but also update bannerURL
Set-PnPListItem -List $listName -Id $itemId -Values #{"BannerImageUrl" = $newBannerUrl; }
}
}
new here sorry if i mess up the format, also uploaded for safety here :P