Firebase Authentication and Database Rules - firebase

Question

I am new to Flutter/Dart but I have been trying to figure out the DB rules for a project that I am working on. I know that there are numerous posts on SO about Firebase DB rules but everything that I have found and tried has not worked. In the particular case below I want anyone to be able to read the data but only the author to be able to write and edit it. I set the Doc ID to be the uid and that works fine with permissions removed but I cannot get anything to work when I add restricted rules. What am I doing wrong?
Stack Trace Message
I/flutter (17900): PlatformException(Error performing setData, PERMISSION_DENIED: Missing or insufficient permissions., null)
E/flutter (17900): [ERROR:flutter/lib/ui/ui_dart_state.cc(157)] Unhandled Exception: setState() called after dispose(): _RegisterState#1360e(lifecycle state: defunct, not mounted)
My Firebase Rules:
service cloud.firestore {
match /databases/{database}/documents {
match /brews/{userId} {
allow read: if request.auth.uid != null;
allow write: if request.auth.uid == userId;
}
}
}
Database Code
class DatabaseService {
final String uid;
DatabaseService({this.uid});
//Collection reference
final CollectionReference brewCollection =
Firestore.instance.collection('brews');
Future updateUserData(String sugars, String name, int strength) async {
return await brewCollection.document(uid).setData({
'sugars': sugars,
'name': name,
'strength': strength,
});
}
//brew list from snapshot
List<Brew> _brewListFromSnapshot(QuerySnapshot snapshot) {
return snapshot.documents.map((doc) {
return Brew(
name: doc.data['name'] ?? '',
strength: doc.data['strength'] ?? 0,
sugars: doc.data['sugars'] ?? '0',
);
}).toList();
}
//userData from snapshot
UserData _userDataFromSnapshot(DocumentSnapshot snapshot) {
return UserData(
uid: uid,
name: snapshot.data['name'],
sugars: snapshot.data['sugars'],
strength: snapshot.data['strength'],
);
}
//Get the collection stream
Stream<List<Brew>> get brews {
return brewCollection.snapshots().map(_brewListFromSnapshot);
}
//get user doc stream
Stream<UserData> get userData {
return brewCollection.document(uid).snapshots().map(_userDataFromSnapshot);
}
}
Authentication Code:
class Authenticate extends StatefulWidget {
#override
_AuthenticateState createState() => _AuthenticateState();
}
class _AuthenticateState extends State<Authenticate> {
bool showSignIn = true;
void toggleView() {
setState(() {
showSignIn = !showSignIn;
});
}
#override
Widget build(BuildContext context) {
if (showSignIn) {
return SignIn(toggleView: toggleView);
} else {
return Register(toggleView: toggleView);
}
}
}

Answer 1

Your rules are correct, and your update function is correct. Your authentication code doesn't show us if you perform a firebase auth login though.
The only thing that could stop it from working is if you are not logged in (authenticated via firebase authentication) OR you passed the wrong uid String to your DatabaseService class. If that's the case you wont have a request.auth.uid so the rule will fail.
You can test your rules in the console, or you can try isolate the exact payload in your code to provide us more info.