Microsoft Graph API - Determine if calendar event already exists - C#

Question

I am inserting calendar events into our domain users O365 calendars with Microsoft Graph API. I need to determine if the event exists, but my research has only shown how to use the GraphClient.Me.Events scenario to search. I don't believe this would work as we have global access to all calendars (Calendars.ReadWrite) within our domain.

Is there any way to search for the event in the applicable domain users calendar before sync?

var scopes = new string[] { "https://graph.microsoft.com/.default" };
var confidentialClient = ConfidentialClientApplicationBuilder.Create(clientId).WithTenantId(tenantId).WithClientSecret(clientSecret).Build();
var authResult = await confidentialClient.AcquireTokenForClient(scopes).ExecuteAsync();
            
using (HttpClient c = new HttpClient())
{
    string url = "https://graph.microsoft.com/v1.0/users/" + userEmail + " /calendar/events";
    ToOutlookCalendar createOutlookEvent = CreateEvent();

    HttpContent httpContent = new StringContent(JsonConvert.SerializeObject(createOutlookEvent), Encoding.UTF8, "application/json");
    HttpRequestMessage request = new HttpRequestMessage(HttpMethod.Post, url);
    request.Content = httpContent;
    request.Headers.Authorization = new AuthenticationHeaderValue("Bearer", authResult.AccessToken);

var response = await c.SendAsync(request);
var responseString = await response.Content.ReadAsStringAsync();  
}

The calendar event is currently very simple for testing

public static ToOutlookCalendar CreateEvent()
{
     ToOutlookCalendar outlookEvent = new ToOutlookCalendar
     {
          Subject = "Code test migration appt",
          Body = new Body
          {
              ContentType = "HTML",
              Content = "Testing API with application client authorization"
          },
          Start = new End
          {
               DateTime = "2020-06-22T12:30:00",TimeZone = System.TimeZone.CurrentTimeZone.StandardName
          },
          End = new End
          {
               DateTime = "2020-06-22T14:00:00",TimeZone = System.TimeZone.CurrentTimeZone.StandardName
          },
          Location = new LocationName
          {
               DisplayName = "Sample Location"
          }
     };
     return outlookEvent;
}

GavinB GavinB · Accepted Answer · 2020-06-23T18:37:31

Assuming you're targeting the default calendar for the user, yes.

the /me path segment is an alias to the upn or userId, so something like:
"https://graph.microsoft.com/v1.0/users/" + userEmail + "/calendar/events?$filter=subject eq '" + knownTitle + "'"
Should work just fine if you're using an app only token with sufficent permissions

Microsoft Graph API - Determine if calendar event already exists - C#

1 Answers