Converting Firebase Token to String using Flutter - firebase

Question

I have an application that is supposed to send the Firebase Token from my Flutter app to an ASP.Net App Server. The endpoint on the app server works - the request from the Flutter app to the App Server is not working.
The reason it is not working is because when I try to send the token, the token doesn't appear to have arrived yet - it's of type Future. How do I turn that token into a string when it finally arrives?
I've tried turning the token directly into a string in the fcmStream.Listen function, I've also tried turning it into a string using _firebaseMessaging.getToken. Neither of them work
FirebaseMessaging _firebaseMessaging = new FirebaseMessaging();
#override
void initState() {
// TODO: implement initState
super.initState();
location.onLocationChanged().listen((value) {
if (this.mounted) {
setState(() {
currentLocation = value;
});
}
});
_firebaseMessaging.configure(
onMessage: (Map<String, dynamic> message) {
print('on message $message');
},
onResume: (Map<String, dynamic> message) {
print('on resume $message');
},
onLaunch: (Map<String, dynamic> message) {
print('on launch $message');
},
);
_firebaseMessaging.requestNotificationPermissions(
const IosNotificationSettings(sound: true, badge: true, alert: true));
String clientToken = _firebaseMessaging.getToken().then((token) {
print("Token Init: " + token.toString());
}
).toString();
BackendService.postToken(clientToken.toString(), "email#gmail.com");
#override
Stream<String> fcmStream = _firebaseMessaging.onTokenRefresh;
fcmStream.listen((token) {
/*print("Token On Refresh: " + token);
BackendService.postToken(token.toString(), "email#gmail.com");*/
}
);
fcmStream.toString();
class BackendService {
static Future<String> postToken(String token, String hostEmail) async {
final responseBody = (await http.get(
'realurlomitted/.../Meets/RegisterDevice?token=$token&hostEmail=$hostEmail')).body;
print(" Response: " + responseBody.toString());
return responseBody.toString();
}
}
Whenever the token.toString prints, it prints the token just fine - I can see that. It just seems like whenever it tries to make the post using http, the token hasn't arrived from whatever getToken is.
If I can turn that Futrure into a string by awaiting it or something, it would solve my problem so that the $token parameter is the token as a string.
More specifically, my request URL should look like:
https://-----/Meets/RegisterDevice?token=c6V49umapn0:Jdsf90832094890s324&hostEmail=email#gmail.com
But it looks like:
https://-----/Meets/RegisterDevice?token=instance of Future<Dynamic>&hostEmail=email#gmail.com
In the Flutter debugger

Answer 1

As you said, awaiting the future will solve your problem. You can write an async function and put the code in your initState inside it and use await, or you can do this:
_firebaseMessaging.getToken().then((token) {
final tokenStr = token.toString();
// do whatever you want with the token here
}
);

Answer 2

This style is now available
FirebaseAuth.instance.currentUser().then((user) {
if (user != null) {
user.getIdToken().then((token) {
Map<dynamic,dynamic> tokenMap = token.claims;
print(tokenMap['sub']);
});
}
});
so this complete code
#override
void initState() {
FirebaseAuth.instance.currentUser().then((user) {
if (user != null) {
user.getIdToken().then((token) {
Map<dynamic,dynamic> tokenMap = token.claims;
print(tokenMap['sub']);
});
}
});
super.initState();
}