问题
I have a Firebase WebApp which provides info to a user. In addition to the app I need to send push notifications via Firebase Cloud Messaging to users with an Android App.
Goal: The user should have one login to the app which both registers them for notifications and loads the WebApp through a WebView.
Problem: I can't find an approach which achieves this with a single login. In every case I need to login once for the native app and then once again through the webView.
First, some references for others who may be figuring things out:
Firebase Auth UI: https://firebase.google.com/docs/auth/android/firebaseui
Firebase DB: https://firebase.google.com/docs/database/android/read-and-write
Firebase Cloud Messaging: https://firebase.google.com/docs/cloud-messaging/android/topic-messaging
Background: I'm able to process each authentication separately using Firebase Auth UI to handle the notification auth natively and then process the webView authentication through the firebase server. This works but is a poor user experience. Since the native authentication already supplies a token I should, somehow, be able to skip the second stage and sign the user in directly. Here's the approaches I've tried:
FIRST APPROACH:
Native sign-on followed by webapp sign on (working but requires two logins): By following the Firebase Auth UI tutorial I can complete a successful sign in:
FirebaseUser user = FirebaseAuth.getInstance().getCurrentUser();
'user' is not null and can be used to read data from firebase database. Topics IDs are then used to subscribe to topics per FCM documentation.
With notifications subscribed we then establish a connection to the webapp using this line:
myWebView.loadUrl("https://someproject.appspot.com/index.html");
SECOND APPROACH:
Pass user token with myWebView.loadUrl() (authorization is rejected) ...Based on this info: https://firebase.google.com/docs/cloud-messaging/auth-server
Something similar to this, I expect:
...
FirebaseUser user = FirebaseAuth.getInstance().getCurrentUser();
if (user != null) {
//get the user id token
user.getIdToken(true).addOnCompleteListener(new
OnCompleteListener<GetTokenResult>() {
public void onComplete(@NonNull Task<GetTokenResult> task) {
if (task.isSuccessful()) {
//here is the idToken
String idToken = task.getResult().getToken();
}}}}
HashMap<String, String> map = new HashMap<String, String>();
String bearer = "Bearer " + idToken;
//Create header of the form "Authorization: Bearer <token>"
map.put("Authorization",bearer);
myWebView.loadUrl("https://someproject.appspot.com/index.html", map);
...
*This seems to be the mostly likely way this is intended to work, maybe I need to add some code server-side to process the request explicitly rather than relying on the onStateChanged handler? Have also attempted using ?auth= and ?access_token= based on: https://firebase.google.com/docs/database/rest/auth#authenticate_with_an_id_token Sort of shooting in the dark here....
THIRD APPROACH:
Open webApp and trigger onAuthStateChanged when authorization is finished. (Handler never seems to fire. I suspect no FirebaseAuth object is impacted by webView)
...
//Register a FirebaseAuth Listener
FirebaseAuth.AuthStateListener mAuthListener = new FirebaseAuth.AuthStateListener() {
@Override
public void onAuthStateChanged(@NonNull FirebaseAuth firebaseAuth) {
FirebaseUser user = firebaseAuth.getCurrentUser();
if (user != null) {
//Register notification subscriptions per tutorial
}
...
myWebView.loadUrl("https://someproject.appspot.com/index.html");
It seems like there is a best practise here that is not well documented in the firebase tutorials. This also seems like a typical task for someone using firebase on Android. Can someone offer an approach that registers the notification topics and accesses a webApp in one login? What am I missing?
The expected results are to have a single login, following which the user has access to the web app and is registered for individual push notifications.
来源：https://stackoverflow.com/questions/58368242/how-to-pass-firebase-auth-token-to-webview-and-register-for-notifications-on-and