I have list of my contacts on the phone and list of all app users in Firestore. The users on Firestore have field with phone number. I wish to get from Firestore only the users that I have on the phone. My options:
- Get all users from Firestore and then do sync with local contacts. Do not wish to do so due to long sync and security threat.
- For each local contact chech if he exist in Firebase and then get it. Also long sync and many separate request.
- Write cloud function to do it.
My question is if I can avoid cloud function and send list of phone numbers (String) to Firestore and retrieve only documents with phone field that exist on the list?