How can I get user id in sync function

Hi, I am going to use sync gateway to synchronise data between iOS devices. Here is my sync config, and in the function requireUser and access I need to get user id as their parameters.
{ "log": ["CRUD", "REST+", "Access"], "facebook": { "register": true }, "databases": { "group": { "server": "walrus:", "users": { "GUEST": {"disabled": true} }, "sync":
function (doc, oldDoc) {
channel(“group”);
requireUser(“1809472385950210”);
access(“1809472385950210”, “group”);
}
} } }
This user id 1809472385950210 can be found in sync gate way log, but how can I get it directly in sync function?
2016-06-26T16:30:07.056+09:00 HTTP: #011: PUT /group/_local/39a4ac10120436a1f6f598bf56c90ef63fd45e3d (as 1809472385950210) 2016-06-26T16:30:51.541+09:00 HTTP: #012: GET /group/_session 2016-06-26T16:30:51.541+09:00 HTTP: #013: GET /group/_session 2016-06-26T16:30:51.545+09:00 HTTP: #014: POST /group/_facebook 2016-06-26T16:30:51.545+09:00 HTTP: #015: POST /group/_facebook 2016-06-26T16:30:51.756+09:00 HTTP: #016: GET /group/_local/2cba18c37eb9d1bbd4d903cac6289d4c557c810a (as 1809472385950210) 2016-06-26T16:30:51.757+09:00 HTTP: #016: --> 404 missing (1.7 ms) 2016-06-26T16:30:51.762+09:00 HTTP: #017: POST /group/_changes (as 1809472385950210) 2016-06-26T16:30:51.767+09:00 HTTP: #018: POST /group/_changes (as 1809472385950210) 2016-06-26T16:30:51.932+09:00 HTTP: #019: GET /group/_local/81dc0c0c1b6f7b70a1ba2fceafd59bd7857b817a (as 1809472385950210) 2016-06-26T16:30:51.932+09:00 HTTP: #019: --> 404 missing (0.2 ms) 2016-06-26T16:30:51.935+09:00 HTTP: #020: POST /group/_revs_diff (as 1809472385950210) 2016-06-26T16:30:51.939+09:00 HTTP: #021: POST /group/_bulk_docs (as 1809472385950210)

Hi, usually you would not hardcode group or user name in the sync function. You would store them in the document. Please take a look at this example: http://developer.couchbase.com/documentation/mobile/current/get-started/get-started-mobile/cloud-sync-function/sync-function-example/index.html

Yes, I do not want to hardcode, it is just a demo. In the function requireUser(“1809472385950210”), I want to get the id which is created by Facebook auth, but how can I can this id? You can see in the log, it appears after all the http request url.

@lm2343635

There is no way to retrieve the user id of the active user context in the sync function.

This is by design, during a _resync, all documents are passed through the sync function and at that time there is no authenticated user as the process runs as Admin.

If a sync function were to rely on the user ID being available it would fail for _resync operations.

When a document is created on a client, you would normally have the authenticated userid available, add a property to the document that contains that userid. In your sync function require that the current authenticated user match that doc.userid by calling requireUser(doc.userid) .

This approach works during a _resync as all the sync function require…() methods will return without error.