Create an Event with a specific iCalUid - json

Question

Is there a way to create an event in Office calendar ( with the Graph API ) setting the iCalUId?
I have tested with the Graph Explorer tool (from the web site) inserting this event (POST /v1.0/me/events):
{
"subject": "My event",
"start": {
"dateTime": "2018-02-19T10:39:01.355Z",
"timeZone": "UTC"
},
"end": {
"dateTime": "2018-02-26T10:39:01.355Z",
"timeZone": "UTC"
},
"iCalUid": "040000008200E00074C5B7101A82E00800000000F44A7CFB6DA9D301000000000000000100000004A4B349D0E9F1744BBA2F67E4D522179"
}
The system creates my event correctly, but it changes the UID with another ( auto-created, I suppose).
This is a part of the JSON response:
{
"iCalUId": "040000008200E00074C5B7101A82E008000000005BBB3A076EA9D301000000000000000010000000389E2C56CB68B74E807FE83A5CC60AAB",
"subject": "My event",
"start": {
"dateTime": "2018-02-19T10:39:01.3550000",
"timeZone": "UTC"
},
"end": {
"dateTime": "2018-02-26T10:39:01.3550000",
"timeZone": "UTC"
}
}
From the documentation only the ID field is read-only, so I am wondering if there is a way to set the iCalUId.

Answer 1

iCalUid is a read-only calculated value so it cannot be manually set. You can see the details on how it is calculated in the PidLidGlobalObjectId Property documentation.

Answer 2

Here's an undocumented way (as far as I can tell, anyway) to modify the iCalUId. I've only tested with creation and not with updating, but I think it should work. Note that I don't know what other side-effects this will have, but for my use-case, it has worked so far.
The iCalUId gets its value from the PidLidGlobalObjectId property. You can modify this value using SingleValueExtendedProperties. For instances of recurring events, the iCalUId uses the PidLidCleanGlobalObjectId which oddly enough doesn't calculate its value from the normal PidLidGlobalObjectId, so you'll want to modify that too.
{
"subject": "Subject",
"start": ...,
"end": ...,
// the rest of your event request
"singleValueExtendedProperties": [
// PidLidGlobalObjectId
{
"id": "Binary {6ED8DA90-450B-101B-98DA-00AA003F1305} Id 0x003",
"value": "" // base-64 encoded PidLidGlobalObjectId, it should start with BAAAA...
},
// PidLidCleanGlobalObjectId
{
"id": "Binary {6ED8DA90-450B-101B-98DA-00AA003F1305} Id 0x023",
"value": "" // base-64 encoded PidLidCleanGlobalObjectId, it should start with BAAAA...
}
]
}
Be sure to check out the format
of the PidLidGlobalObjectId and PidLidCleanGlobalObjectId, otherwise you might get "Data is corrupt" or some other such errors when trying to create or update events.