An issue that I’ve now run into a few times now so I thought it was worth a blog post – if you are using the REST Custom sensor within PRTG Network Monitor you may see the error below if you have generated your REST configuration using PowerShell.
XML: The returned XML does not match the expected schema. (code: PE233) — JSON: The returned JSON does not match the expected structure (Invalid JSON.). (code: PE231)
The cause is the default encoding from PowerShell is UCS-2 LE BOM as shown in Notepad++ below.
The fix is simple in that when generating your REST configuration append -Encoding utf8 at the end of the Out-File command. I’ve also seen this apply to a few other situations when using PowerShell to output some form of text – in particular feeds for Palo Alto Networks Next Generation Firewalls.

One of my favourite features of PowerShell is the Invoke-RestMethod cmdlet which (among a great many other things) can download the data from an RSS feed. One application I’ve found for this is to stay on top of security bulletins from organisations like Adobe and Drupal.

However just downloading the data from the feed and kicking it out in an email isn’t quite good enough for my needs thus the script below gets data from a CSV which contains the URL to the feed as well as some extra details to inject into any email notification (e.g. a link to the guide on how to deploy Adobe Updates).

In my production environment this script creates tickets on a FreskDesk helpdesk to log and manage any new update notifications. In the attached example below the script just fires off email notifications.

Have a look at the screenshot sequence below for more info!

  Get-Rss (4.0 KiB, 686 hits)

Update 09/05/2017 – v0.2 – Now handles XML and Arrays in the link and title objects (good for reddit and blogspot!)