feat(fcm): Add sendEach and sendEachForMulticast for FCM batch se…

…nd (#2138)

* Deprecate sendAll and sendMulticast (#2094)

1. Deprecate sendAll and sendMulticast
2. Add dummy implementation for sendEach and sendEachForMulticast to avoid errors reported by api-extractor

* Implement `sendEach` and `sendEachForMulticast` (#2097)

`sendEach` vs `sendAll`
1. `sendEach` sends one HTTP request to V1 Send endpoint for each
    message in the array.
   `sendAll` sends only one HTTP request to V1 Batch Send endpoint
    to send all messages in the array.
2. `sendEach` calls `Promise.allSettled` to wait for all
   `httpClient.send` calls to complete and construct a `BatchResponse`.
    An `httpClient.send` call to V1 Send endpoint either completes
    with a success or throws an error. So if an error is thrown out,
    the error will be caught in `sendEach` and turned into a
    `SendResponse` with an error.
    Therefore, unlike `sendAll`, `sendEach` does not always throw
    an error for a total failure. It can also return a `BatchResponse`
    with only errors in it.

`sendEachForMulticast` calls `sendEach` under the hood.

* Add integration tests for `sendEach` and `sendMulticast` (#2130)

* Avoid using "-- i.e." in the function comment

etc/firebase-admin.messaging.api.md

@@ -184,7 +184,11 @@ export type Message = TokenMessage | TopicMessage | ConditionMessage;
 export class Messaging {
     get app(): App;
     send(message: Message, dryRun?: boolean): Promise<string>;
+    // @deprecated
     sendAll(messages: Message[], dryRun?: boolean): Promise<BatchResponse>;
+    sendEach(messages: Message[], dryRun?: boolean): Promise<BatchResponse>;
+    sendEachForMulticast(message: MulticastMessage, dryRun?: boolean): Promise<BatchResponse>;
+    // @deprecated
     sendMulticast(message: MulticastMessage, dryRun?: boolean): Promise<BatchResponse>;
     sendToCondition(condition: string, payload: MessagingPayload, options?: MessagingOptions): Promise<MessagingConditionResponse>;
     // @deprecated

src/messaging/messaging-api-request-internal.ts

@@ -96,6 +96,34 @@ export class FirebaseMessagingRequestHandler {
       });
   }
 
+  /**
+   * Invokes the request handler with the provided request data.
+   *
+   * @param host - The host to which to send the request.
+   * @param path - The path to which to send the request.
+   * @param requestData - The request data.
+   * @returns A promise that resolves with the {@link SendResponse}.
+   */
+  public invokeRequestHandlerForSendResponse(host: string, path: string, requestData: object): Promise<SendResponse> {
+    const request: HttpRequestConfig = {
+      method: FIREBASE_MESSAGING_HTTP_METHOD,
+      url: `https://${host}${path}`,
+      data: requestData,
+      headers: LEGACY_FIREBASE_MESSAGING_HEADERS,
+      timeout: FIREBASE_MESSAGING_TIMEOUT,
+    };
+    return this.httpClient.send(request).then((response) => {
+      return this.buildSendResponse(response);
+    })
+      .catch((err) => {
+        if (err instanceof HttpError) {
+          return this.buildSendResponseFromError(err);
+        }
+        // Re-throw the error if it already has the proper format.
+        throw err;
+      });
+  }
+
   /**
    * Sends the given array of sub requests as a single batch to FCM, and parses the result into
    * a BatchResponse object.
@@ -136,4 +164,11 @@ export class FirebaseMessagingRequestHandler {
     }
     return result;
   }
+
+  private buildSendResponseFromError(err: HttpError): SendResponse {
+    return {
+      success: false,
+      error: createFirebaseError(err)
+    };
+  }
 }

src/messaging/messaging.ts

@@ -39,6 +39,7 @@ import {
   MessagingConditionResponse,
   DataMessagePayload,
   NotificationMessagePayload,
+  SendResponse,
 } from './messaging-api';
 
 // FCM endpoints
@@ -250,6 +251,124 @@ export class Messaging {
       });
   }
 
+  /**
+  * Sends each message in the given array via Firebase Cloud Messaging.
+  *
+  * Unlike {@link Messaging.sendAll}, this method makes a single RPC call for each message
+  * in the given array.
+  *
+  * The responses list obtained from the return value corresponds to the order of `messages`.
+  * An error from this method or a `BatchResponse` with all failures indicates a total failure,
+  * meaning that none of the messages in the list could be sent. Partial failures or no
+  * failures are only indicated by a `BatchResponse` return value.
+  *
+  * @param messages - A non-empty array
+  *   containing up to 500 messages.
+  * @param dryRun - Whether to send the messages in the dry-run
+  *   (validation only) mode.
+  * @returns A Promise fulfilled with an object representing the result of the
+  *   send operation.
+  */
+  public sendEach(messages: Message[], dryRun?: boolean): Promise<BatchResponse> {
+    if (validator.isArray(messages) && messages.constructor !== Array) {
+      // In more recent JS specs, an array-like object might have a constructor that is not of
+      // Array type. Our deepCopy() method doesn't handle them properly. Convert such objects to
+      // a regular array here before calling deepCopy(). See issue #566 for details.
+      messages = Array.from(messages);
+    }
+
+    const copy: Message[] = deepCopy(messages);
+    if (!validator.isNonEmptyArray(copy)) {
+      throw new FirebaseMessagingError(
+        MessagingClientErrorCode.INVALID_ARGUMENT, 'messages must be a non-empty array');
+    }
+    if (copy.length > FCM_MAX_BATCH_SIZE) {
+      throw new FirebaseMessagingError(
+        MessagingClientErrorCode.INVALID_ARGUMENT,
+        `messages list must not contain more than ${FCM_MAX_BATCH_SIZE} items`);
+    }
+    if (typeof dryRun !== 'undefined' && !validator.isBoolean(dryRun)) {
+      throw new FirebaseMessagingError(
+        MessagingClientErrorCode.INVALID_ARGUMENT, 'dryRun must be a boolean');
+    }
+
+    return this.getUrlPath()
+      .then((urlPath) => {
+        const requests: Promise<SendResponse>[] = copy.map((message) => {
+          validateMessage(message);
+          const request: { message: Message; validate_only?: boolean } = { message };
+          if (dryRun) {
+            request.validate_only = true;
+          }
+          return this.messagingRequestHandler.invokeRequestHandlerForSendResponse(FCM_SEND_HOST, urlPath, request);
+        });
+        return Promise.allSettled(requests);
+      }).then((results) => {
+        const responses: SendResponse[] = [];
+        results.forEach(result => {
+          if (result.status === 'fulfilled') {
+            responses.push(result.value);
+          } else { // rejected
+            responses.push({ success: false, error: result.reason })
+          }
+        })
+        const successCount: number = responses.filter((resp) => resp.success).length;
+        return {
+          responses,
+          successCount,
+          failureCount: responses.length - successCount,
+        };
+      });
+  }
+
+  /**
+   * Sends the given multicast message to all the FCM registration tokens
+   * specified in it.
+   *
+   * This method uses the {@link Messaging.sendEach} API under the hood to send the given
+   * message to all the target recipients. The responses list obtained from the
+   * return value corresponds to the order of tokens in the `MulticastMessage`.
+   * An error from this method or a `BatchResponse` with all failures indicates a total
+   * failure, meaning that the messages in the list could be sent. Partial failures or
+   * failures are only indicated by a `BatchResponse` return value.
+   *
+   * @param message - A multicast message
+   *   containing up to 500 tokens.
+   * @param dryRun - Whether to send the message in the dry-run
+   *   (validation only) mode.
+   * @returns A Promise fulfilled with an object representing the result of the
+   *   send operation.
+   */
+  public sendEachForMulticast(message: MulticastMessage, dryRun?: boolean): Promise<BatchResponse> {
+    const copy: MulticastMessage = deepCopy(message);
+    if (!validator.isNonNullObject(copy)) {
+      throw new FirebaseMessagingError(
+        MessagingClientErrorCode.INVALID_ARGUMENT, 'MulticastMessage must be a non-null object');
+    }
+    if (!validator.isNonEmptyArray(copy.tokens)) {
+      throw new FirebaseMessagingError(
+        MessagingClientErrorCode.INVALID_ARGUMENT, 'tokens must be a non-empty array');
+    }
+    if (copy.tokens.length > FCM_MAX_BATCH_SIZE) {
+      throw new FirebaseMessagingError(
+        MessagingClientErrorCode.INVALID_ARGUMENT,
+        `tokens list must not contain more than ${FCM_MAX_BATCH_SIZE} items`);
+    }
+
+    const messages: Message[] = copy.tokens.map((token) => {
+      return {
+        token,
+        android: copy.android,
+        apns: copy.apns,
+        data: copy.data,
+        notification: copy.notification,
+        webpush: copy.webpush,
+        fcmOptions: copy.fcmOptions,
+      };
+    });
+    return this.sendEach(messages, dryRun);
+  }
+
   /**
    * Sends all the messages in the given array via Firebase Cloud Messaging.
    * Employs batching to send the entire list as a single RPC call. Compared
@@ -258,8 +377,8 @@ export class Messaging {
    *
    * The responses list obtained from the return value
    * corresponds to the order of tokens in the `MulticastMessage`. An error
-   * from this method indicates a total failure -- i.e. none of the messages in
-   * the list could be sent. Partial failures are indicated by a `BatchResponse`
+   * from this method indicates a total failure, meaning that none of the messages
+   * in the list could be sent. Partial failures are indicated by a `BatchResponse`
    * return value.
    *
    * @param messages - A non-empty array
@@ -268,6 +387,8 @@ export class Messaging {
    *   (validation only) mode.
    * @returns A Promise fulfilled with an object representing the result of the
    *   send operation.
+   *
+   * @deprecated Use {@link Messaging.sendEach} instead.
    */
   public sendAll(messages: Message[], dryRun?: boolean): Promise<BatchResponse> {
     if (validator.isArray(messages) && messages.constructor !== Array) {
@@ -316,16 +437,18 @@ export class Messaging {
    * This method uses the `sendAll()` API under the hood to send the given
    * message to all the target recipients. The responses list obtained from the
    * return value corresponds to the order of tokens in the `MulticastMessage`.
-   * An error from this method indicates a total failure -- i.e. the message was
-   * not sent to any of the tokens in the list. Partial failures are indicated by
-   * a `BatchResponse` return value.
+   * An error from this method indicates a total failure, meaning that the message
+   * was not sent to any of the tokens in the list. Partial failures are indicated
+   * by a `BatchResponse` return value.
    *
    * @param message - A multicast message
    *   containing up to 500 tokens.
    * @param dryRun - Whether to send the message in the dry-run
    *   (validation only) mode.
    * @returns A Promise fulfilled with an object representing the result of the
    *   send operation.
+   *
+   * @deprecated Use {@link Messaging.sendEachForMulticast} instead.
    */
   public sendMulticast(message: MulticastMessage, dryRun?: boolean): Promise<BatchResponse> {
     const copy: MulticastMessage = deepCopy(message);

test/integration/messaging.spec.ts

@@ -108,6 +108,37 @@ describe('admin.messaging', () => {
       });
   });
 
+  it('sendEach()', () => {
+    const messages: Message[] = [message, message, message];
+    return getMessaging().sendEach(messages, true)
+      .then((response) => {
+        expect(response.responses.length).to.equal(messages.length);
+        expect(response.successCount).to.equal(messages.length);
+        expect(response.failureCount).to.equal(0);
+        response.responses.forEach((resp) => {
+          expect(resp.success).to.be.true;
+          expect(resp.messageId).matches(/^projects\/.*\/messages\/.*$/);
+        });
+      });
+  });
+
+  it('sendEach(500)', () => {
+    const messages: Message[] = [];
+    for (let i = 0; i < 500; i++) {
+      messages.push({ topic: `foo-bar-${i % 10}` });
+    }
+    return getMessaging().sendEach(messages, true)
+      .then((response) => {
+        expect(response.responses.length).to.equal(messages.length);
+        expect(response.successCount).to.equal(messages.length);
+        expect(response.failureCount).to.equal(0);
+        response.responses.forEach((resp) => {
+          expect(resp.success).to.be.true;
+          expect(resp.messageId).matches(/^projects\/.*\/messages\/.*$/);
+        });
+      });
+  });
+
   it('sendAll()', () => {
     const messages: Message[] = [message, message, message];
     return getMessaging().sendAll(messages, true)
@@ -139,6 +170,25 @@ describe('admin.messaging', () => {
       });
   });
 
+  it('sendEachForMulticast()', () => {
+    const multicastMessage: MulticastMessage = {
+      data: message.data,
+      android: message.android,
+      tokens: ['not-a-token', 'also-not-a-token'],
+    };
+    return getMessaging().sendEachForMulticast(multicastMessage, true)
+      .then((response) => {
+        expect(response.responses.length).to.equal(2);
+        expect(response.successCount).to.equal(0);
+        expect(response.failureCount).to.equal(2);
+        response.responses.forEach((resp) => {
+          expect(resp.success).to.be.false;
+          expect(resp.messageId).to.be.undefined;
+          expect(resp.error).to.have.property('code', 'messaging/invalid-argument');
+        });
+      });
+  });
+
   it('sendMulticast()', () => {
     const multicastMessage: MulticastMessage = {
       data: message.data,