Integrate MailChimp Campaigns API with SPO to create wiki pages based on email sent from MailChimp

$mailChimpApiKey = ""
$siteUrl = "https://<your-sharepoint-site-url>"
$relativeUrl = "/sites/<your-site-name>"
$wikiFolder = "$relativeUrl/SitePages/WikiFolder/"
$wikiPageUrl = "$relativeUrl/SitePages/"
$apiEndpoint = "https://<DC>.api.mailchimp.com/3.0/campaigns"
#On line 85, replace the search string for your campaign - NOTE LINE NUMBERS MAY CHANGE
#On line 101, provide the local path to where the images should be stored for later upload to SPO
#On line 107 and 110, replace WikiDocLib with the existing document library on SPO to store images
function Connect-ToSharePoint {
    param (
        [string]$siteUrl
    )
    #The sample uses a certificate to connect. You can also use -WebLogin but -Interactive is no longer supported
    $connectToSP = Connect-PnPOnline -Url $siteUrl -ClientId "<your-client-id>" -Thumbprint "<your-thumbprint>" -Tenant "<your-tenant-id>" -ReturnConnection
    return $connectToSP
}

function Get-MailChimpCampaigns {
    param (
        [string]$mailChimpApiKey,
        [string]$sinceSendTime,
        [string]$beforeSendTime
    )
    $headers = @{
        "Authorization" = "Bearer $mailChimpApiKey"
    }
    $apiEndpoint = "$apiEndpoint?since_send_time=$sinceSendTime&before_send_time=$beforeSendTime&sort_field=send_time&sort_dir=DESC&status=sent"
    $response = Invoke-RestMethod -Uri $apiEndpoint -Headers $headers -Method Get
    return $response
}

function Extract-HTMLContent {
    param (
        [string]$mailChimpUrl,
        [object]$headers
    )
    $response = Invoke-RestMethod -Uri $mailChimpUrl -Headers $headers -Method Get
    return $response.html
}

function Clean-HTMLContent {
    param (
        [string]$htmlContent
    )
    $pattern = '<body[^>]*>([\s\S]*?)<\/body>'
    if ($htmlContent -match $pattern) {
        $bodyContent = $matches[1]
        $bodyContent = $bodyContent -replace '<script[^>]*>[\s\S]*?<\/script>', ''
        $bodyContent = $bodyContent -replace '<style[^>]*>[\s\S]*?<\/style>', ''
        $bodyContent = $bodyContent -replace '<!--[\s\S]*?-->', ''
    } else {
        $bodyContent = "No body content found"
    }
    return $bodyContent
}

function Create-PublishWikiPage {
    param (
        [object]$connectToSP,
        [string]$pageTitle,
        [string]$bodyContent
    )
    $pageName = $pageTitle
    Add-PnPWikiPage -ServerRelativePageUrl "$wikiPageUrl$pageName" -Content $bodyContent -Connection $connectToSP
    Move-PnPFile -SourceUrl "SitePages/$pageName" -TargetUrl "$wikiFolder$pageName" -Overwrite -Force -Connection $connectToSP

    $mContext = Get-PnPContext -Connection $connectToSP
    $newPageAsListItem = Get-PnPFile -Url "$wikiFolder$pageName" -AsListItem -Connection $connectToSP
    $newPageAsFile = $newPageAsListItem.File
    $mContext.Load($newPageAsFile)
    $mContext.ExecuteQuery()
    $newPageAsFile.Publish("Published via PowerShell script to automate")
    $mContext.ExecuteQuery()
}


$connectToSP = Connect-ToSharePoint -siteUrl $siteUrl
$currentYear = (Get-Date).Year
$currentMonth = (Get-Date).Month
$sinceSendTime = (Get-Date -Year $currentYear -Month $currentMonth -Day 1).ToString("yyyy-MM-ddTHH:mm:ssZ")
$beforeSendTime = (Get-Date).ToString("yyyy-MM-ddT23:59:59Z")
$jsonCampaignResponse = Get-MailChimpCampaigns -mailChimpApiKey $mailChimpApiKey -sinceSendTime $sinceSendTime -beforeSendTime $beforeSendTime

if ($jsonCampaignResponse.campaigns[0].settings.subject_line.Contains("<REPLACE WITH STRING TO FIND ON MC>")) {
    Write-Host $jsonCampaignResponse.campaigns[0].settings.subject_line
    $campaignId = $jsonCampaignResponse.campaigns[0].Id
}

$pageTitle = "{0}.{1}" -f $jsonCampaignResponse.campaigns[0].settings.subject_line, "aspx"
$mailChimpUrl = "$apiEndpoint/$campaignId/content"
$htmlContent = Extract-HTMLContent -mailChimpUrl $mailChimpUrl -headers $headers
$bodyContent = Clean-HTMLContent -htmlContent $htmlContent

$imageSrcMatches = [regex]::Matches($bodyContent, '<img[^>]+src="([^">]+)"')
$imageSrcs = foreach ($match in $imageSrcMatches) { $match.Groups[1].Value }

$imagePaths = @()
foreach ($src in $imageSrcs) {
    $fileName = [System.IO.Path]::GetFileName($src)
    $filePath = "C:\users\<your-user-name>\downloads\TESTIMG\$filename"
    Invoke-WebRequest -Uri $src -OutFile $filePath
    $imagePaths += $filePath
}

$newFolderName = $jsonCampaignResponse.campaigns[0].settings.subject_line
Add-PnpFolder -Name $newFolderName -Folder "WikiDocLib" -ErrorAction Continue -Connection $connectToSP
$newImageUrls = @()
foreach ($imagePath in $imagePaths) {
    $uploadedFile = Add-PnPFile -Path $imagePath -Folder "WikiDocLib/$newFolderName" -Connection $connectToSP
    $newImageUrls += $uploadedFile.ServerRelativeUrl
}

$updatedHtml = $bodyContent
for ($i = 0; $i -lt $imageSrcs.Count; $i++) {
    $oldSrc = [regex]::Escape($imageSrcs[$i])
    $newSrc = $newImageUrls[$i]
    $updatedHtml = [regex]::Replace($updatedHtml, "(<img[^>]*src=[""'])$oldSrc([""'][^>]*>)", "`$1$newSrc`$2")
}

$bodyContent = $updatedHtml

Create-PublishWikiPage -connectToSP $connectToSP -pageTitle $pageTitle -bodyContent $bodyContent