Calculating the token refresh interval (firebase#27)

hiranya911 · web-flow · commit 16af0bf6910e · 2017-05-08T11:28:03.000-07:00
diff --git a/src/main/java/com/google/firebase/FirebaseApp.java b/src/main/java/com/google/firebase/FirebaseApp.java
@@ -33,6 +33,7 @@
 import com.google.firebase.internal.FirebaseExecutors;
 import com.google.firebase.internal.FirebaseService;
 import com.google.firebase.internal.GetTokenResult;
+import com.google.firebase.internal.Log;
 import com.google.firebase.internal.NonNull;
 import com.google.firebase.internal.Nullable;
 import com.google.firebase.tasks.Continuation;
@@ -339,7 +340,8 @@ Task<GetTokenResult> getToken(boolean forceRefresh) {
             @Override
             public GetTokenResult then(@NonNull Task<GoogleOAuthAccessToken> task)
                 throws Exception {
-              GetTokenResult newToken = new GetTokenResult(task.getResult().getAccessToken());
+              GoogleOAuthAccessToken googleOAuthToken = task.getResult();
+              GetTokenResult newToken = new GetTokenResult(googleOAuthToken.getAccessToken());
               GetTokenResult oldToken = currentToken.get();
               List<AuthStateListener> listenersCopy = null;
               if (!newToken.equals(oldToken)) {
@@ -353,7 +355,15 @@ public GetTokenResult then(@NonNull Task<GoogleOAuthAccessToken> task)
                   // access to the token refresher.
                   if (currentToken.compareAndSet(oldToken, newToken)) {
                     listenersCopy = ImmutableList.copyOf(authStateListeners);
-                    tokenRefresher.scheduleRefresh(TOKEN_REFRESH_INTERVAL_MILLIS);
+                    long refreshDelay  = googleOAuthToken.getExpiryTime() - clock.now()
+                        - TimeUnit.MINUTES.toMillis(5);
+                    if (refreshDelay > 0) {
+                      tokenRefresher.scheduleRefresh(refreshDelay);
+                    } else {
+                      Log.w("FirebaseApp", "Token expiry ("
+                          + googleOAuthToken.getExpiryTime() + ") is less than 5 minutes in the "
+                          + "future. Not scheduling a proactive refresh.");
+                    }
                   }
                 }
               }
