Can a pointer field, to "user" class, be updated via rest api? - parse-platform

Question

I have a class A that has a pointer (pointer field) to the special class User. Is it possible to automatically update the pointer field with the authenticated user, using the Rest API instead of having to call the API like the example bellow?
curl -X POST \
-H "X-Parse-Application-Id: ${APPLICATION_ID}" \
-H "X-Parse-REST-API-Key: ${REST_API_KEY}" \
-H "X-Parse-Session-Token: ${SESSION_TOKEN}" \
-H "Content-Type: application/json" \
-d '{"user":{ "__type": "Pointer", "className": "_User", "objectId": "${id}"}}' \
https://api.parse.com/1/classes/A
I would like to update the User field by just using the call:
curl -X POST \
-H "X-Parse-Application-Id: ${APPLICATION_ID}" \
-H "X-Parse-REST-API-Key: ${REST_API_KEY}" \
-H "X-Parse-Session-Token: ${SESSION_TOKEN}" \
-H "Content-Type: application/json" \
https://api.parse.com/1/classes/A
And an A entry would be created.
A : {Pointer<_User> user_from_session, string objectId}
Any enlightenment is appreciated.
Cheers.

Answer 1

I've managed to accomplish what I wanted by adding an afterSave trigger. When creating A, with an authenticated request, I will read the current user from the session and set the field in the class. Bellow the example.
Parse.Cloud.afterSave("A", function (request, response) {
var record = request.object;
var user = Parse.User.current();
if (record.existed() == false) {
record.set("user", user);
record.save().
then(function (record) {
response.success();
}, function (error) {
response.error();
});
} else {
console.log("[DEBUG] Normal save (A).");
response.success();
}
});
Cheers.