firebase flutter push notificaiton - firebase

Question

I am trying to send push notification from my php application to my flutter apps via Firebase messaging service. while I start the emulator it receives a token from firebase, then i copy that token and can send message. But I want to store that token to my mysql database once i receive the token. I have 2 scenario. For the first time if user install the apps, i'll insert the token to my database so that i can send message using that token. Now I am confused how to update that token every time the user login(not inserting new token again and again to database).
void setupNotification() async{
_firebaseMessaging.
_firebaseMessaging.getToken().then((token){
//insert the token to user database
saveToken(token);
});
Stream<String> fcmStream = _firebaseMessaging.onTokenRefresh;
fcmStream.listen((token) {
//always update the user database with new token
saveToken(token);
});
_firebaseMessaging.configure(
onMessage: (Map<String, dynamic> message) async{
print("message while app is open: $message");
},
onResume: (Map<String, dynamic> message) async{
print("message: $message");
},
onLaunch: (Map<String, dynamic> message) async{
print("message: $message");
}
);
}
I mean how to identify that the token is new or old(updated) ?

Answer 1

You need to create a Locally stored json file in your app using path_provider plugin.This file will get initialized everytime user opens the app and will contain a user Model containing token of user.On the very first page of the app in initState check if the user is not null.
IF NULL:
Get fcm token and store it in database.After storing it in database write the token in your Locally stored file.
ELSE:
Do nothing
Next time when same user opens the app again in initstate it will check if user is not null.This time it will not add a new token in database as our code to insert token into database won't execute.
Example:
We will store user as follows.
class User {
String token;
String platform;
User({
this.token = '',
this.platform = '',
});
Map<String, dynamic> toJson() {
final Map<String, dynamic> data = new Map<String, dynamic>();
data['token'] = this.token;
data['platform'] = this.platform;
return data;
}
User.fromJson(Map<String, dynamic> json): this(
platform: json["platform"],
token: json["token"],
);
}
Local Data file:
class LocalData {
static User _user;
static User get user => _user;
/// Flag for Authentication.
static bool get isTokenAdded=> _user != null;
static loadData() async {
final file = File((await getApplicationDocumentsDirectory()).path + '/data.json');
try {
final data = jsonDecode(await file.readAsString());
_user = User.fromJson(data['user']);
} catch (e) {
print(e);
}
}
static writeData() async {
final file = File((await getApplicationDocumentsDirectory()).path + '/data.json');
await file.writeAsString(jsonEncode({
'user': _user?.toJson(),
}));
}
static void addToken(User user) {
LocalData._user = user;
writeData();
}
static void removeToken() {
LocalData._user = null;
writeData();
}
}
App's main function:
void main() async {
/// Load Local Data.
WidgetsFlutterBinding.ensureInitialized();
await LocalData.loadData();
runApp(YourApp());
}
Now in initState of your apps first page you can check if token is already added in database by
if(LocalData.isTokenAdded()){
//do nothing
}else{
//get token and insert it into database then write it in file:
LocalData.user.token = token;
LocalData.writeData();
}