Using Graph API, how to filter events whose subject does not contain a specific string?

Question

Hello everyone,
I want to use the Graph API to filter events from the Outlook calendar, which do NOT contain a specific string in the subject line.
I followed the following documentation:

• https://learn.microsoft.com/en-us/graph/filter-query-parameter?tabs=http
• https://learn.microsoft.com/en-us/graph/aad-advanced-queries?tabs=http

I created the following query:

https://graph.microsoft.com/v1.0/me/events?$filter=not(contains(subject, 'HOST'))&select=subject,start/dateTime,end/dateTime,onlineMeeting/joinUrl&$count=true

In the request header, I set ConsistencyLevel to eventual as specified in the advanced query documentation.

However, this doesn't work and gives the following error:

{
    "error": {
        "code": "ErrorInternalServerError",
        "message": "An internal server error occurred. The operation failed.",
        "innerError": {
            "date": "2023-02-09T04:11:01",
            "request-id": "a0781ad4-0aac-4774-a30a-15f9a88596aa",
            "client-request-id": "8b988658-0166-b9a8-812d-88413dc01b6f"
        }
    }
}

I couldn't figure out what is wrong with my query. Could someone kindly explain and help me to achieve this?

Answer 1

Hi @Aravind Pai

The $filter query parameters don't yet support not and contains combined, but you can try using code filtering, which I've tested locally and it works perfectly.

var events = await graphClient.Me.Events
      .Request()
      .Select("subject,start,end,onlineMeeting")
      .GetAsync();

foreach (var e in events) {
 
      if (!e.Subject.Contains("HOST")) {
 
            Console.WriteLine(JsonConvert.SerializeObject(e)); 
      } 
}

By the way, $select query parameters are only used to return the properties of the event, not to return the children of the event properties.

---

If the answer is helpful, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment".