fetching user data from firebase and storing it in static variables - firebase

Question

i am new to flutter and firebase development, so i really don't know how much will it cost me to keep fetching user data from firebase in every screen that i need them in, so i decided to fetch them once and store them in class MyUser static variables as follows:
in MyApp class:
bool isAuthenticated = false;
Future checkAuthenticity() async {
AuthService.getCurrentUser().then((user) async {
if (user != null) {
String myUid = await AuthService.getCurrentUID();
await MyUserController().getCurrentUserFromFirebase(myUid);
if (mounted)
setState(() {
isAuthenticated = true;
});
} else {
if (mounted)
setState(() {
isAuthenticated = false;
});
}
});
}
#override
Widget build(BuildContext context) {
home: isAuthenticated ? Home(passedSelectedIndex: 0) : Register(),
}
from the above code, this line await MyUserController().getCurrentUserFromFirebase(myUid); is as follows:
getCurrentUserFromFirebase(String uid) async {
await FirestoreService().getCurrentUserData(uid);
}
from the above code, this line await FirestoreService().getCurrentUserData(uid); is as follows:
Future getCurrentUserData(String uid) async {
try {
var userData = await FirebaseFirestore.instance.collection('users').doc(uid).get();
MyUser.fromData(userData.data());
} catch (e) {
if (e is PlatformException) {
return e.message;
}
return e.toString();
}
}
from the above code, this line MyUser.fromData(userData.data()); is a constructor in
MyUser class as follows:
class MyUser {
static String uid;
static String name;
static String username;
static String email;
static String userAvatarUrl;
static String location;
static String phoneNumber;
MyUser.fromData(Map<String, dynamic> data) {
uid = data['id'];
name = data['name'];
username = data['username'];
email = data['email'];
userAvatarUrl = data['userAvatarUrl'];
location = data['location'];
phoneNumber = data['phoneNumber'];
}
}
and to make use of all of the following, in each page that i need to load the current user data in, i use for example:
var userId = MyUser.uid
or to show the current user name i use Text('${MyUser.name}');
when i close the app completely and relaunch it again, it should check for authenticity, and complete executing the rest of the code in main() function.
so my questions are:
1) does this have any performance issues when we release the app?
2) does this will really will prevent unnecessary reads that i can consume in every page i need the data in ?
3) is there any better approach to prevent unnecessary reads from firebase, for example to save the current user data as strings and a profile image locally?
pardon me for prolonging the question, but i wanted to share the code itself.
any help would be much appreciated.

Answer 1

As a short answer,
You can make a class of SharedPreferences to store data as strings in key: value manner.
So anywhere you want you can get an instance of that class and reach it from anywhere in the app.
If you also declare some functions which will decode string to json you will get a ready user class instance in return of your function which will make it easier.
So when you want to save user info to Local Storage(SharedPreferences) you may use a function which will encode your User object to string and save it to SharedPreferences as below..
user.dart' as theUser; for conflict issues
class SharedPrefs {
static SharedPreferences _sharedPrefs;
init() async {
if (_sharedPrefs == null) {
_sharedPrefs = await SharedPreferences.getInstance();
}
}
dynamic get user=> _sharedPrefs.getString('user')!=null?theUser.User.fromString(_sharedPrefs.getString('user')):null;
set user(theUser.User user)=> _sharedPrefs.setString('user', jsonEncode(user));
String get accessToken=> _sharedPrefs.getString('access_token');
set accessToken(String accessToken)=> _sharedPrefs.setString('access_token', accessToken);
void removeString(String entry){
_sharedPrefs.remove(entry);
}
}
final sharedPrefs = SharedPrefs();
And in the app anywhere you can use it directly by typing sharedPrefs.user