so there is a Firestore load problem if there is no internet.
There should not be any problems when the user has no internet connection, and this is because Firestore has its own default caching mechanism:
For Android and iOS, offline persistence is enabled by default.
You say:
When the user comes back home, he will have wifi but the app is closed and will not sync.
It won't sync unless you are listening for real-time changes. Besides that, it's always recommended to remove the lister according to the life-cycle of your activity. So if you are using addSnapshotListener() you attach a listener that gets called for every change that takes place in your database. So this is happening also when your app is closed. Not removing the listener might produce unwanted bills. So it's mandatory to detach the listeners before the activity gets destroyed. For more info, please check the following links:
#1. It's not recommended to do that. However, JobDispatcher is old and deprecated, and no longer available, not the BroadcastReceiver class. But if need, you should use WorkManager instead. If you must absolutely use JobDispatcher, which I recommend against it, the source code is archived here. So please read about how to migrate from JobDispatcher to WorkManager.
#2.
Can I use test DB for production and change permissions to read-only? Does that test DB have an expiration date?
Each database has its own Security Rules. So you should choose to secure your data according to your needs. However, there is no expiration date involved, but you can use something like this:
rules_version = '2';
service cloud.firestore {
match /databases/{database}/documents {
match /{document=**} {
allow read, write: if request.time < timestamp.date(2021, 08, 05);
}
}
}
To limit the access to the database until tomorrow, August 5th, 2021.
#3. You can use the database also without security rules. But most likely you should consider using them. Most likely you shouldn't use the username, nor the email address, but UID that comes from the authentication process.
#4. Yes, every CRUD operation counts against your free quota. And yes, there's a minimum of one document read, even if the query yields no results. So if your query doesn't return any results, you have to pay one document read.
