How to set epoch in Firestore using server time

Question

I\'m trying to set the epoch when data is created in Firestore. I\'m looking to get some similar result to what is done in the real-time database, using ServerValue.TI

Answer 1

The object that results from setting a Firestore field with FieldValue.serverTimestamp() is an instance of java.util.Date. When you later read the value, you can get the epoch time using getTime().

As an example, for a document created like this:

Map doc = new HashMap<>();
doc.put("timestamp", FieldValue.serverTimestamp());

The resulting value can be read like this:

docRef.get().addOnCompleteListener(new OnCompleteListener() {
    @Override
    public void onComplete(@NonNull Task task) {
        if (task.isSuccessful()) {
            DocumentSnapshot snapshot = task.getResult();
            if (snapshot != null) {
                Map map = snapshot.getData();
                Date date = (Date) map.get("timestamp");
                Log.d(TAG, "date=" + date);
                Log.d(TAG, "time=" + date.getTime());
            } else {
                Log.d(TAG, "No such document");
            }
        } else {
            Log.d(TAG, "get() failed with ", task.getException());
        }
    }
});