Microsoft Graph PowerShell Invoke-RestMethod to POST to the Calendar with multiple events

Question

I have following PowerShell script which add event on the Office 365 group calendar. When I run the following script, it will only add the first event but not the second one. And there is no error. Have I missed anything on the script? Any help on this would be much appreciated, thank you.

$json = @"
  {
    "subject": "Event1",
    "start": {
      "timeZone": "UTC",
      "dateTime": "2023-06-10T08:00"
    },
    "end": {
      "timeZone": "UTC",
      "dateTime": "2023-06-10T09:00"
    }
  },
  {
    "subject": "Event2",
    "start": {
      "timeZone": "UTC",
      "dateTime": "2023-06-11T08:00"
    },
    "end": {
      "timeZone": "UTC",
      "dateTime": "2023-06-11T09:00"
    }
  }
"@
$apiUrl = "https://graph.microsoft.com/v1.0/groups/xxxx-xxxx-xxxx-xxx/events"
Invoke-RestMethod -Headers @{Authorization = "Bearer $($Tokenresponse.access_token)"} -Uri $apiUrl -Method Post -ContentType "application/json" -Body $json

Answer 1

You cannot use the Graph API to create multiple events at once, to create multiple events you have to use batching, see this link for more information:

See an example here:

{  
  "requests": [  
    {  
      "id": "1",  
      "method": "POST",  
      "url": "/groups/{id}/calendar/events",  
      "body": { "event 1 body here" },  
      "headers": {  
        "Content-Type": "application/json"  
      }  
    },  
    {  
      "id": "2",  
      "method": "POST",  
      "url": "/groups/{id}/calendar/events",  
      "body": {"event 2 body here"},  
      "headers": {  
        "Content-Type": "application/json"  
      }  
    }
  ]  
}  

Answer 2

The endpoint https://graph.microsoft.com/v1.0/groups/xxxx-xxxx-xxxx-xxx/events allows to add only one event. So the second event is ignored.

Use batch endpoint

$json = @"
{
    "requests": [
        {
            "url": "/groups/xxx/events",
            "method": "POST",
            "id": "1",
            "body": {
                "subject": "Event1",
                "start": {
                "timeZone": "UTC",
                "dateTime": "2023-06-10T08:00"
                },
                "end": {
                "timeZone": "UTC",
                "dateTime": "2023-06-10T09:00"
                }
            },
            "headers": {
                "Content-Type": "application/json"
            }
        },
        {
            "url": "/groups/xxx/events",
            "method": "POST",
            "id": "1",
            "body": {
                "subject": "Event2",
                "start": {
                "timeZone": "UTC",
                "dateTime": "2023-06-11T08:00"
                },
                "end": {
                "timeZone": "UTC",
                "dateTime": "2023-06-11T09:00"
                }
            },
            "headers": {
                "Content-Type": "application/json"
            }
        }
    ]
}
"@
$apiUrl = "https://graph.microsoft.com/v1.0/`$batch"
Invoke-RestMethod -Headers @{Authorization = "Bearer $($Tokenresponse.access_token)"} -Uri $apiUrl -Method Post -ContentType "application/json" -Body $json

Answer 3

I am getting following error

Response status code does not indicate success: 405 (Method Not Allowed).

Same json works fine from https://developer.microsoft.com/en-us/graph/graph-explorer

$json = @"
{
    "requests": [
        {
            "url": "/groups/xxx/events",
            "method": "POST",
            "id": "1",
            "body": {
                "subject": "Event1",
                "start": {
                    "timeZone": "UTC",
                    "dateTime": "2023-06-10T08:00"
                },
                "end": {
                    "timeZone": "UTC",
                    "dateTime": "2023-06-10T09:00"
                }
            },
            "headers": {
                "Content-Type": "application/json"
            }
        },
        {
            "url": "/groups/xxx/events",
            "method": "POST",
            "id": "2",
            "body": {
                "subject": "Event2",
                "start": {
                    "timeZone": "UTC",
                    "dateTime": "2023-06-10T08:00"
                },
                "end": {
                    "timeZone": "UTC",
                    "dateTime": "2023-06-10T09:00"
                }
            },
            "headers": {
                "Content-Type": "application/json"
            }
        }
    ]
}
"@
$apiUrl = "https://graph.microsoft.com/v1.0/$batch"
Invoke-RestMethod -Headers @{Authorization = "Bearer $($Tokenresponse.access_token)"} -Uri $apiUrl -Method Post -ContentType "application/json" -Body $json