Implementing breaking API changes for FirebaseCredential API

src/main/java/com/google/firebase/FirebaseApp.java

@@ -27,6 +27,7 @@
 import com.google.common.base.Strings;
 import com.google.common.collect.ImmutableList;
 import com.google.common.io.BaseEncoding;
+import com.google.firebase.auth.GoogleOAuthAccessToken;
 import com.google.firebase.internal.AuthStateListener;
 import com.google.firebase.internal.FirebaseAppStore;
 import com.google.firebase.internal.FirebaseExecutors;
@@ -67,8 +68,10 @@ public class FirebaseApp {
 
  public static final String DEFAULT_APP_NAME = "[DEFAULT]";
  private static final long TOKEN_REFRESH_INTERVAL_MILLIS = TimeUnit.MINUTES.toMillis(55);
- private static final TokenRefresher.Factory DEFAULT_TOKEN_REFRESHER_FACTORY =
+
+ static final TokenRefresher.Factory DEFAULT_TOKEN_REFRESHER_FACTORY =
  new TokenRefresher.Factory();
+ static final Clock DEFAULT_CLOCK = new Clock();
 
  /**
  * Global lock for synchronizing all SDK-wide application state changes. Specifically, any
@@ -79,23 +82,28 @@ public class FirebaseApp {
  private final String name;
  private final FirebaseOptions options;
  private final TokenRefresher tokenRefresher;
+ private final Clock clock;
 
  private final AtomicBoolean deleted = new AtomicBoolean();
  private final List<AuthStateListener> authStateListeners = new ArrayList<>();
  private final AtomicReference<GetTokenResult> currentToken = new AtomicReference<>();
  private final Map<String, FirebaseService> services = new HashMap<>();
 
+ private Task<GoogleOAuthAccessToken> previousTokenTask;
+
  /**
  * Per application lock for synchronizing all internal FirebaseApp state changes.
  */
  private final Object lock = new Object();
 
  /** Default constructor. */
- private FirebaseApp(String name, FirebaseOptions options, TokenRefresher.Factory factory) {
+ private FirebaseApp(String name, FirebaseOptions options,
+ TokenRefresher.Factory factory, Clock clock) {
  checkArgument(!Strings.isNullOrEmpty(name));
  this.name = name;
  this.options = checkNotNull(options);
- tokenRefresher = checkNotNull(factory).create(this);
+ this.tokenRefresher = checkNotNull(factory).create(this);
+ this.clock = checkNotNull(clock);
  }
 
  /** Returns a list of all FirebaseApps. */
@@ -168,11 +176,11 @@ public static FirebaseApp initializeApp(FirebaseOptions options) {
  * @throws IllegalStateException if an app with the same name has already been initialized.
  */
  public static FirebaseApp initializeApp(FirebaseOptions options, String name) {
- return initializeApp(options, name, DEFAULT_TOKEN_REFRESHER_FACTORY);
+ return initializeApp(options, name, DEFAULT_TOKEN_REFRESHER_FACTORY, DEFAULT_CLOCK);
  }
 
- static FirebaseApp initializeApp(
- FirebaseOptions options, String name, TokenRefresher.Factory tokenRefresherFactory) {
+ static FirebaseApp initializeApp(FirebaseOptions options, String name,
+ TokenRefresher.Factory tokenRefresherFactory, Clock clock) {
  FirebaseAppStore appStore = FirebaseAppStore.initialize();
  String normalizedName = normalize(name);
  final FirebaseApp firebaseApp;
@@ -181,7 +189,7 @@ static FirebaseApp initializeApp(
  !instances.containsKey(normalizedName),
  "FirebaseApp name " + normalizedName + " already exists!");
 
- firebaseApp = new FirebaseApp(normalizedName, options, tokenRefresherFactory);
+ firebaseApp = new FirebaseApp(normalizedName, options, tokenRefresherFactory, clock);
  instances.put(normalizedName, firebaseApp);
  }
 
@@ -305,6 +313,13 @@ private void checkNotDeleted() {
  checkState(!deleted.get(), "FirebaseApp was deleted %s", this);
  }
 
+ private boolean refreshRequired(
+ @NonNull Task<GoogleOAuthAccessToken> previousTask, boolean forceRefresh) {
+ return (previousTask.isComplete()
+ && (forceRefresh || !previousTask.isSuccessful()
+ || previousTask.getResult().getExpiryTime() <= clock.now()));
+ }
+
  /**
  * Internal-only method to fetch a valid Service Account OAuth2 Token.
  *
@@ -313,41 +328,45 @@ private void checkNotDeleted() {
  * @return a {@link Task}
  */
  Task<GetTokenResult> getToken(boolean forceRefresh) {
- checkNotDeleted();
- return options
- .getCredential()
- .getAccessToken(forceRefresh)
- .continueWith(
- new Continuation<String, GetTokenResult>() {
- @Override
- public GetTokenResult then(@NonNull Task<String> task) throws Exception {
- GetTokenResult newToken = new GetTokenResult(task.getResult());
- GetTokenResult oldToken = currentToken.get();
- List<AuthStateListener> listenersCopy = null;
- if (!newToken.equals(oldToken)) {
- synchronized (lock) {
- if (deleted.get()) {
- return newToken;
- }
-
- // Grab the lock before compareAndSet to avoid a potential race
- // condition with addAuthStateListener. The same lock also ensures serial
- // access to the token refresher.
- if (currentToken.compareAndSet(oldToken, newToken)) {
- listenersCopy = ImmutableList.copyOf(authStateListeners);
- tokenRefresher.scheduleRefresh(TOKEN_REFRESH_INTERVAL_MILLIS);
- }
+ synchronized (lock) {
+ checkNotDeleted();
+ if (previousTokenTask == null || refreshRequired(previousTokenTask, forceRefresh)) {
+ previousTokenTask = options.getCredential().getAccessToken();
+ }
+
+ return previousTokenTask.continueWith(
+ new Continuation<GoogleOAuthAccessToken, GetTokenResult>() {
+ @Override
+ public GetTokenResult then(@NonNull Task<GoogleOAuthAccessToken> task)
+ throws Exception {
+ GetTokenResult newToken = new GetTokenResult(task.getResult().getAccessToken());
+ GetTokenResult oldToken = currentToken.get();
+ List<AuthStateListener> listenersCopy = null;
+ if (!newToken.equals(oldToken)) {
+ synchronized (lock) {
+ if (deleted.get()) {
+ return newToken;
  }
- }
 
- if (listenersCopy != null) {
- for (AuthStateListener listener : listenersCopy) {
- listener.onAuthStateChanged(newToken);
+ // Grab the lock before compareAndSet to avoid a potential race
+ // condition with addAuthStateListener. The same lock also ensures serial
+ // access to the token refresher.
+ if (currentToken.compareAndSet(oldToken, newToken)) {
+ listenersCopy = ImmutableList.copyOf(authStateListeners);
+ tokenRefresher.scheduleRefresh(TOKEN_REFRESH_INTERVAL_MILLIS);
  }
  }
- return newToken;
  }
- });
+
+ if (listenersCopy != null) {
+ for (AuthStateListener listener : listenersCopy) {
+ listener.onAuthStateChanged(newToken);
+ }
+ }
+ return newToken;
+ }
+ });
+ }
  }
 
  boolean isDefaultApp() {
@@ -451,4 +470,10 @@ TokenRefresher create(FirebaseApp app) {
  }
  }
  }
+
+ static class Clock {
+ long now() {
+ return System.currentTimeMillis();
+ }
+ }
 }

src/main/java/com/google/firebase/auth/FirebaseAuth.java

@@ -129,7 +129,7 @@ public Task<String> createCustomToken(
  }
 
  return ((FirebaseCredentials.CertCredential) credential)
- .getCertificate(false)
+ .getCertificate()
  .continueWith(
  new Continuation<GoogleCredential, String>() {
  @Override

src/main/java/com/google/firebase/auth/FirebaseCredential.java

@@ -26,10 +26,12 @@
 public interface FirebaseCredential {
 
  /**
- * Returns a Google OAuth2 access token used to authenticate with Firebase services.
+ * Returns a Google OAuth2 access token which can be used to authenticate with Firebase services.
+ * This method does not cache tokens, and therefore each invocation will fetch a fresh token.
+ * The caller is expected to implement caching by referencing the token expiry details
+ * available in the returned GoogleOAuthAccessToken instance.
  *
- * @param forceRefresh Whether to fetch a new token or use a cached one if available.
- * @return A {@link Task} providing an access token.
+ * @return A {@link Task} providing a Google OAuth access token.
  */
- Task<String> getAccessToken(boolean forceRefresh);
+ Task<GoogleOAuthAccessToken> getAccessToken();
 }

src/main/java/com/google/firebase/auth/FirebaseCredentials.java

@@ -142,39 +142,24 @@ abstract static class BaseCredential implements FirebaseCredential {
 
  final HttpTransport transport;
  final JsonFactory jsonFactory;
- final Clock clock;
- private final Object accessTokenTaskLock = new Object();
  private GoogleCredential googleCredential;
- private Task<FirebaseAccessToken> accessTokenTask;
 
  BaseCredential(HttpTransport transport, JsonFactory jsonFactory) {
- this(transport, jsonFactory, new Clock());
- }
-
- BaseCredential(HttpTransport transport, JsonFactory jsonFactory, Clock clock) {
  this.transport = checkNotNull(transport, "HttpTransport must not be null");
  this.jsonFactory = checkNotNull(jsonFactory, "JsonFactory must not be null");
- this.clock = checkNotNull(clock, "Clock must not be null");
  }
 
  /** Retrieves a GoogleCredential. Should not use caching. */
  abstract GoogleCredential fetchCredential() throws IOException;
 
- /** Retrieves an access token from a GoogleCredential. Should not use caching. */
- abstract FirebaseAccessToken fetchToken(GoogleCredential credential) throws IOException;
-
  /**
  * Returns the associated GoogleCredential for this class. This implementation is cached by
  * default.
- *
- * @param forceRefresh Whether to fetch from cache
  */
- final Task<GoogleCredential> getCertificate(boolean forceRefresh) {
- if (!forceRefresh) {
- synchronized (this) {
- if (googleCredential != null) {
- return Tasks.forResult(googleCredential);
- }
+ final Task<GoogleCredential> getCertificate() {
+ synchronized (this) {
+ if (googleCredential != null) {
+ return Tasks.forResult(googleCredential);
  }
  }
 
@@ -193,44 +178,21 @@ public GoogleCredential call() throws Exception {
  });
  }
 
- private boolean refreshRequired(
- @NonNull Task<FirebaseAccessToken> previousTask, boolean forceRefresh) {
- return previousTask == null
- || (previousTask.isComplete()
- && (forceRefresh
- || !previousTask.isSuccessful()
- || previousTask.getResult().isExpired()));
- }
+ abstract GoogleOAuthAccessToken fetchToken(GoogleCredential credential) throws IOException;
 
  /**
- * Returns an access token for this credential. This implementation is cached by default.
- *
- * @param forceRefresh Whether or not to force an access token refresh
+ * Returns an access token for this credential. Does not cache tokens.
  */
  @Override
- public final Task<String> getAccessToken(boolean forceRefresh) {
- synchronized (accessTokenTaskLock) {
- if (refreshRequired(accessTokenTask, forceRefresh)) {
- accessTokenTask =
- getCertificate(forceRefresh)
- .continueWith(
- new Continuation<GoogleCredential, FirebaseAccessToken>() {
- @Override
- public FirebaseAccessToken then(@NonNull Task<GoogleCredential> task)
- throws Exception {
- return fetchToken(task.getResult());
- }
- });
- }
-
- return accessTokenTask.continueWith(
- new Continuation<FirebaseAccessToken, String>() {
- @Override
- public String then(@NonNull Task<FirebaseAccessToken> task) throws Exception {
- return task.getResult().getToken();
- }
- });
- }
+ public final Task<GoogleOAuthAccessToken> getAccessToken() {
+ return getCertificate()
+ .continueWith(new Continuation<GoogleCredential, GoogleOAuthAccessToken>() {
+ @Override
+ public GoogleOAuthAccessToken then(@NonNull Task<GoogleCredential> task)
+ throws Exception {
+ return fetchToken(task.getResult());
+ }
+ });
  }
  }
 
@@ -267,9 +229,9 @@ GoogleCredential fetchCredential() throws IOException {
  }
 
  @Override
- FirebaseAccessToken fetchToken(GoogleCredential credential) throws IOException {
+ GoogleOAuthAccessToken fetchToken(GoogleCredential credential) throws IOException {
  credential.refreshToken();
- return new FirebaseAccessToken(credential, clock);
+ return newAccessToken(credential);
  }
 
  Task<String> getProjectId() {
@@ -290,9 +252,9 @@ GoogleCredential fetchCredential() throws IOException {
  }
 
  @Override
- FirebaseAccessToken fetchToken(GoogleCredential credential) throws IOException {
+ GoogleOAuthAccessToken fetchToken(GoogleCredential credential) throws IOException {
  credential.refreshToken();
- return new FirebaseAccessToken(credential, clock);
+ return newAccessToken(credential);
  }
  }
 
@@ -322,9 +284,9 @@ GoogleCredential fetchCredential() throws IOException {
  }
 
  @Override
- FirebaseAccessToken fetchToken(GoogleCredential credential) throws IOException {
+ GoogleOAuthAccessToken fetchToken(GoogleCredential credential) throws IOException {
  credential.refreshToken();
- return new FirebaseAccessToken(credential, clock);
+ return newAccessToken(credential);
  }
  }
 
@@ -334,35 +296,9 @@ private static class DefaultCredentialsHolder {
  applicationDefault(Utils.getDefaultTransport(), Utils.getDefaultJsonFactory());
  }
 
- static class Clock {
-
- protected long now() {
- return System.currentTimeMillis();
- }
- }
-
- static class FirebaseAccessToken {
-
- private final String token;
- private final long expirationTime;
- private final Clock clock;
-
- FirebaseAccessToken(GoogleCredential credential, Clock clock) {
- checkNotNull(credential, "Google credential is required");
-
- token =
- checkNotNull(
- credential.getAccessToken(), "Access token should not be null after refresh.");
- expirationTime = credential.getExpirationTimeMilliseconds();
- this.clock = checkNotNull(clock, "Clock is required");
- }
-
- String getToken() {
- return token;
- }
-
- boolean isExpired() {
- return expirationTime < clock.now();
- }
+ static GoogleOAuthAccessToken newAccessToken(GoogleCredential credential) {
+ checkNotNull(credential);
+ return new GoogleOAuthAccessToken(credential.getAccessToken(),
+ credential.getExpirationTimeMilliseconds());
  }
 }