Added FCM Root URL in FirebaseOptions

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

@@ -74,6 +74,7 @@ public GoogleCredentials get() {
       };
 
   private final String databaseUrl;
+  private final String fcmRootUrl;
   private final String storageBucket;
   private final Supplier<GoogleCredentials> credentialsSupplier;
   private final Map<String, Object> databaseAuthVariableOverride;
@@ -101,6 +102,11 @@ private FirebaseOptions(@NonNull final FirebaseOptions.Builder builder) {
     } else {
       this.serviceAccountId = null;
     }
+    if (!Strings.isNullOrEmpty(builder.fcmRootUrl)) {
+      this.fcmRootUrl = builder.fcmRootUrl;
+    } else {
+      this.fcmRootUrl = null;
+    }
     this.storageBucket = builder.storageBucket;
     this.httpTransport = builder.httpTransport != null ? builder.httpTransport
       : ApiClientUtils.getDefaultTransport();
@@ -124,6 +130,15 @@ public String getDatabaseUrl() {
     return databaseUrl;
   }
 
+  /**
+   * Returns the Fcm Root URL that is used for Fcm Messaging.
+   *
+   * @return The Fcm Messaging URL supplied via {@link Builder#setFcmRootUrl}.
+   */
+  public String getFcmRootUrl() {
+    return fcmRootUrl;
+  }
+
   /**
    * Returns the name of the Google Cloud Storage bucket used for storing application data.
    *
@@ -260,6 +275,7 @@ public static final class Builder {
     private ThreadManager threadManager;
     private int connectTimeout;
     private int readTimeout;
+    private String fcmRootUrl;
 
     /**
      * Constructs an empty builder.
@@ -290,6 +306,7 @@ public Builder(FirebaseOptions options) {
       connectTimeout = options.connectTimeout;
       readTimeout = options.readTimeout;
       firestoreOptions = options.firestoreOptions;
+      fcmRootUrl = options.fcmRootUrl;
     }
 
     /**
@@ -306,6 +323,20 @@ public Builder setDatabaseUrl(@Nullable String databaseUrl) {
       return this;
     }
 
+    /**
+     * Sets the Fcm Root URL to use for Fcm Messaging.
+     *
+     * <p>See <a href="https://firebase.google.com/docs/admin/setup#initialize_the_sdk">
+     * Initialize the SDK</a> for code samples and detailed documentation.
+     *
+     * @param fcmRootUrl The Fcm Root URL to use for Fcm Messaging.
+     * @return This <code>Builder</code> instance is returned so subsequent calls can be chained.
+     */
+    public Builder setFcmRootUrl(@Nullable String fcmRootUrl) {
+      this.fcmRootUrl = fcmRootUrl;
+      return this;
+    }
+
     /**
      * Sets the name of the Google Cloud Storage bucket for reading and writing application data.
      * This should be the full name of the bucket as listed in the

src/main/java/com/google/firebase/messaging/FirebaseMessagingClientImpl.java

@@ -59,15 +59,17 @@
  * A helper class for interacting with Firebase Cloud Messaging service.
  */
 final class FirebaseMessagingClientImpl implements FirebaseMessagingClient {
-
-  private static final String FCM_URL = "https://fcm.googleapis.com/v1/projects/%s/messages:send";
+  private static final String FCM_ROOT_URL = "https://fcm.googleapis.com";
+  private static final String FCM_SEND_PATH = "v1/projects/%s/messages:send";
+  private static final String FCM_BATCH_PATH = "batch";
 
   private static final Map<String, String> COMMON_HEADERS =
       ImmutableMap.of(
           "X-GOOG-API-FORMAT-VERSION", "2",
           "X-Firebase-Client", "fire-admin-java/" + SdkUtils.getVersion());
 
   private final String fcmSendUrl;
+  private final String fcmBatchUrl;
   private final HttpRequestFactory requestFactory;
   private final HttpRequestFactory childRequestFactory;
   private final JsonFactory jsonFactory;
@@ -78,22 +80,33 @@ final class FirebaseMessagingClientImpl implements FirebaseMessagingClient {
 
   private FirebaseMessagingClientImpl(Builder builder) {
     checkArgument(!Strings.isNullOrEmpty(builder.projectId));
-    this.fcmSendUrl = String.format(FCM_URL, builder.projectId);
+    String fcmRootUrl = Strings.isNullOrEmpty(builder.fcmRootUrl) ? FCM_ROOT_URL :
+            builder.fcmRootUrl;
+    this.fcmSendUrl = String.format(String.format(
+                    "%s/%s", fcmRootUrl, FCM_SEND_PATH),
+            builder.projectId);
+    this.fcmBatchUrl = String.format("%s/%s", fcmRootUrl, FCM_BATCH_PATH);
     this.requestFactory = checkNotNull(builder.requestFactory);
     this.childRequestFactory = checkNotNull(builder.childRequestFactory);
     this.jsonFactory = checkNotNull(builder.jsonFactory);
     this.responseInterceptor = builder.responseInterceptor;
     this.errorHandler = new MessagingErrorHandler(this.jsonFactory);
     this.httpClient = new ErrorHandlingHttpClient<>(requestFactory, jsonFactory, errorHandler)
       .setInterceptor(responseInterceptor);
-    this.batchClient = new MessagingBatchClient(requestFactory.getTransport(), jsonFactory);
+    this.batchClient = new MessagingBatchClient(requestFactory.getTransport(),
+            jsonFactory, fcmRootUrl);
   }
 
   @VisibleForTesting
   String getFcmSendUrl() {
     return fcmSendUrl;
   }
 
+  @VisibleForTesting
+  String getFcmBatchUrl() {
+    return fcmBatchUrl;
+  }
+
   @VisibleForTesting
   HttpRequestFactory getRequestFactory() {
     return requestFactory;
@@ -139,7 +152,7 @@ private BatchResponse sendBatchRequest(
       return new BatchResponseImpl(callback.getResponses());
     } catch (HttpResponseException e) {
       OutgoingHttpRequest req = new OutgoingHttpRequest(
-          HttpMethods.POST, MessagingBatchClient.FCM_BATCH_URL);
+          HttpMethods.POST, fcmBatchUrl);
       IncomingHttpResponse resp = new IncomingHttpResponse(e, req);
       throw errorHandler.handleHttpResponseException(e, resp);
     } catch (IOException e) {
@@ -193,6 +206,7 @@ static FirebaseMessagingClientImpl fromApp(FirebaseApp app) {
         .setRequestFactory(ApiClientUtils.newAuthorizedRequestFactory(app))
         .setChildRequestFactory(ApiClientUtils.newUnauthorizedRequestFactory(app))
         .setJsonFactory(app.getOptions().getJsonFactory())
+        .setFcmRootUrl(app.getOptions().getFcmRootUrl())
         .build();
   }
 
@@ -207,9 +221,15 @@ static final class Builder {
     private HttpRequestFactory childRequestFactory;
     private JsonFactory jsonFactory;
     private HttpResponseInterceptor responseInterceptor;
+    private String fcmRootUrl;
 
     private Builder() { }
 
+    Builder setFcmRootUrl(String fcmRootUrl) {
+      this.fcmRootUrl = fcmRootUrl;
+      return this;
+    }
+
     Builder setProjectId(String projectId) {
       this.projectId = projectId;
       return this;
@@ -319,22 +339,17 @@ private MessagingServiceErrorResponse safeParse(String response) {
 
   private static class MessagingBatchClient extends AbstractGoogleJsonClient {
 
-    private static final String FCM_ROOT_URL = "https://fcm.googleapis.com";
-    private static final String FCM_BATCH_PATH = "batch";
-    private static final String FCM_BATCH_URL = String.format(
-        "%s/%s", FCM_ROOT_URL, FCM_BATCH_PATH);
-
-    MessagingBatchClient(HttpTransport transport, JsonFactory jsonFactory) {
-      super(new Builder(transport, jsonFactory));
+    MessagingBatchClient(HttpTransport transport, JsonFactory jsonFactory, String fcmRootUrl) {
+      super(new Builder(transport, jsonFactory, fcmRootUrl));
     }
 
     private MessagingBatchClient(Builder builder) {
       super(builder);
     }
 
     private static class Builder extends AbstractGoogleJsonClient.Builder {
-      Builder(HttpTransport transport, JsonFactory jsonFactory) {
-        super(transport, jsonFactory, FCM_ROOT_URL, "", null, false);
+      Builder(HttpTransport transport, JsonFactory jsonFactory, String fcmRootUrl) {
+        super(transport, jsonFactory, fcmRootUrl, "", null, false);
         setBatchPath(FCM_BATCH_PATH);
         setApplicationName("fire-admin-java");
       }

src/test/java/com/google/firebase/FirebaseOptionsTest.java

@@ -44,6 +44,7 @@
 public class FirebaseOptionsTest {
 
   private static final String FIREBASE_DB_URL = "https://mock-project.firebaseio.com";
+  private static final String FIREBASE_FCM_URL = "https://localhost";
   private static final String FIREBASE_STORAGE_BUCKET = "mock-storage-bucket";
   private static final String FIREBASE_PROJECT_ID = "explicit-project-id";
 
@@ -53,6 +54,7 @@ public class FirebaseOptionsTest {
           .setStorageBucket(FIREBASE_STORAGE_BUCKET)
           .setProjectId(FIREBASE_PROJECT_ID)
           .setCredentials(TestUtils.getCertCredential(ServiceAccount.EDITOR.asStream()))
+          .setFcmRootUrl(FIREBASE_FCM_URL)
           .build();
 
   private static final ThreadManager MOCK_THREAD_MANAGER = new ThreadManager() {
@@ -88,8 +90,10 @@ public void createOptionsWithAllValuesSet() throws IOException {
             .setConnectTimeout(30000)
             .setReadTimeout(60000)
             .setFirestoreOptions(firestoreOptions)
+            .setFcmRootUrl(FIREBASE_FCM_URL)
             .build();
     assertEquals(FIREBASE_DB_URL, firebaseOptions.getDatabaseUrl());
+    assertEquals(FIREBASE_FCM_URL, firebaseOptions.getFcmRootUrl());
     assertEquals(FIREBASE_STORAGE_BUCKET, firebaseOptions.getStorageBucket());
     assertEquals(FIREBASE_PROJECT_ID, firebaseOptions.getProjectId());
     assertSame(jsonFactory, firebaseOptions.getJsonFactory());
@@ -183,6 +187,7 @@ public void checkToBuilderCreatesNewEquivalentInstance() {
     assertNotSame(ALL_VALUES_OPTIONS, allValuesOptionsCopy);
     assertEquals(ALL_VALUES_OPTIONS.getCredentials(), allValuesOptionsCopy.getCredentials());
     assertEquals(ALL_VALUES_OPTIONS.getDatabaseUrl(), allValuesOptionsCopy.getDatabaseUrl());
+    assertEquals(ALL_VALUES_OPTIONS.getFcmRootUrl(), allValuesOptionsCopy.getFcmRootUrl());
     assertEquals(ALL_VALUES_OPTIONS.getProjectId(), allValuesOptionsCopy.getProjectId());
     assertEquals(ALL_VALUES_OPTIONS.getJsonFactory(), allValuesOptionsCopy.getJsonFactory());
     assertEquals(ALL_VALUES_OPTIONS.getHttpTransport(), allValuesOptionsCopy.getHttpTransport());

src/test/java/com/google/firebase/messaging/FirebaseMessagingClientImplTest.java

@@ -62,7 +62,8 @@
 public class FirebaseMessagingClientImplTest {
 
   private static final String TEST_FCM_URL =
-      "https://fcm.googleapis.com/v1/projects/test-project/messages:send";
+          "https://fcm.googleapis.com/v1/projects/test-project/messages:send";
+  private static final String TEST_FCM_BATCH_URL = "https://fcm.googleapis.com/batch";
 
   private static final List<Integer> HTTP_ERRORS = ImmutableList.of(401, 404, 500);
 
@@ -534,6 +535,7 @@ public void testFromApp() throws IOException {
       FirebaseMessagingClientImpl client = FirebaseMessagingClientImpl.fromApp(app);
 
       assertEquals(TEST_FCM_URL, client.getFcmSendUrl());
+      assertEquals(TEST_FCM_BATCH_URL, client.getFcmBatchUrl());
       assertSame(options.getJsonFactory(), client.getJsonFactory());
 
       HttpRequest request = client.getRequestFactory().buildGetRequest(