How do I monitor BigBlueButton usage?

<#
.SYNOPSIS
PRTG Sensor for BBB server

.PARAMETER serverurl
Full URL to BBB API, e.g. https://your-server/bigbluebutton/api
(no trainling slash please!)

.PARAMETER secret
BBB-Secret (get it by running "bbb-conf --secret")
#>
Param(
	[Parameter( Mandatory=$true)]
    [string]$serverurl,
	[Parameter( Mandatory=$true)]
    [string]$secret
    )
 
# Strange hack to get proper output encoding
# see https://kb.paessler.com/en/topic/64817-how-can-i-show-special-characters-with-exe-script-sensors#reply-210863
ping localhost -n 1 | Out-Null
[Console]::OutputEncoding = [System.Text.Encoding]::UTF8

# Powershell is stupid and tries TLS1.0 by default, then dies at Invoke-WebRequest :-(
[Net.ServicePointManager]::SecurityProtocol = [Net.SecurityProtocolType]::Tls12
 
$api = "getMeetings"

$hasher = [System.Security.Cryptography.SHA1]::Create()
# calculate checksum - see https://docs.bigbluebutton.org/dev/api.html
$bytes = [byte[]][char[]]("$api$secret")
$hash = $hasher.ComputeHash($bytes)
# and convert to hex format
$secret = (($hash | foreach { $_.ToString("X2") }) -join "").toLower()

# build API call url including checksum
$fullurl = "$serverurl/$($api)?&checksum=$secret"
#echo $fullurl
$response = Invoke-WebRequest -URI $fullurl

function send-error
{
	Param([string]$message)
# neccessary for correct output encoding
[Console]::WriteLine(@"
<?xml version=`"1.0`" encoding=`"UTF-8`" ?>
<prtg>
    <error>1</error>
	<text>
	$message
	</text>
</prtg>
"@ )
}

if ($response.StatusCode -ne 200) {
	send-error "Invalid HTTP response code: $($response.StatusCode) - $($response.Content)"
	exit
}

#for debugging:
#echo $response.Content

# convert response to XML object
$xml = [xml]$response.Content
if ($xml.response.returncode -ne "SUCCESS") {
	send-error "API call failed: $($xml.response.message)"
	exit
}

# XML structure:
# response
#   meetings
#     meeting
#       meetingName
#       running (true)
#       participantCount (int)
#		listenerCount (int)
#		voiceParticipantCount (int)
#		videoCount (int)
#		isBreakout -> I'm not sure whether to count them, probably yes

$meetingcount = 0
$runningcount = 0
$participantCount = 0
$listenerCount = 0
$voiceParticipantCount = 0
$videoCount = 0
$resultmessage = "OK"

if ($xml.response.meetings) {
	if ($xml.response.meetings.meeting) {
		$meetingcount = 1
	}
	if ($xml.response.meetings.meeting.Count -gt 0) {
		$meetingcount = $xml.response.meetings.meeting.Count
	}
	$running = $xml.response.meetings | ? { $_.meeting.running -eq "true" }
	foreach ($m in $running.meeting) {
		$runningcount++;
		$participantCount += $m.participantCount
		$listenerCount += $m.listenerCount
		$voiceParticipantCount += $m.voiceParticipantCount
		$videoCount += $m.videoCount
	}
} else {
	$resultmessage = "no active meetings"
}

$result += @"
		<result>
			<value>$meetingcount</value>
			<unit>count</unit>
			<channel>Total meetings</channel>
		</result>
		<result>
			<value>$runningcount</value>
			<unit>count</unit>
			<channel>Total meetings running</channel>
		</result>
		<result>
			<value>$participantCount</value>
			<unit>count</unit>
			<channel>Total participants</channel>
		</result>
		<result>
			<value>$listenerCount</value>
			<unit>count</unit>
			<channel>Total listeners</channel>
		</result>
		<result>
			<value>$voiceParticipantCount</value>
			<unit>count</unit>
			<channel>Total voice participants</channel>
		</result>
		<result>
			<value>$videoCount</value>
			<unit>count</unit>
			<channel>Total video streams</channel>
		</result>
		<text>
		$resultmessage
		</text>
"@

# neccessary for correct output encoding
[Console]::WriteLine(@"
<?xml version=`"1.0`" encoding=`"UTF-8`" ?>
<prtg>
$result
</prtg>
"@ )