OpenExtensions: Find and retrieve Events with a given extension - microsoft-graph-api

Question

I'm looking to write events to a users calendar that correspond objects in my system. I also want the ability to update and/or delete those that change between runs of the process that updates the user's calendar.
To this end I'm using Open Extensions to write additional data onto the Calendar Events that I'm creating. This is working nicely and I can see the Extension data being written.
I can use a $filter to query for events that I have written to the user's calendar:
/v1.0/me/events?$filter=Extensions/any(f: f/id eq '{id}')
This works fine and I'm seeing the results I expect. It's worth noting that the id in this query works just fine with either the fully qualified form of Microsoft.OutlookServices.OpenTypeExtension.{extensionName} or just using the short form of {extensionName}
However I cannot get the events to return with the $expanded Extension. I've tried the examples from the docs but using this query it fails:
/me/events?$filter=Extensions/any(f: f/id eq '{id}')&$expand=Extensions($filter=id eq '{id}')
Like this:
{
"error": {
"code": "BadRequest",
"message": "Parsing Select and Expand failed.",
"innerError": {
"date": "2020-06-19T17:14:59",
"request-id": "d1125156-05a6-499a-b9a4-6c66e5ce377d"
}
}
}
I need the expanded Extension data to correlate the Calendar event back to the objects in my system to allow for updates or deletes as needed.
Does anyone know what might be happening or how to resolve this?

Answer 1

I got an answer through another question: Receiving 400s and 500s when attempting to get singleValueExtendedProperties
The issue is that the = symbol inside the $expand expression needs to be uriEncoded. The correct query to use is: /me/events?$filter=Extensions/any(f: f/id eq '{id}')&$expand=Extensions($filter%3Did eq '{id}')