Add support to set/update custom signals

- Also takes care of setting the signals in the fetch request

Author: ashish-kothari

common/api-review/remote-config.api.md

@@ -9,6 +9,11 @@ import { FirebaseApp } from '@firebase/app';
 // @public
 export function activate(remoteConfig: RemoteConfig): Promise<boolean>;
 
+// @alpha
+export type CustomSignals = {
+    [key: string]: string | number;
+};
+
 // @public
 export function ensureInitialized(remoteConfig: RemoteConfig): Promise<void>;
 
@@ -62,6 +67,11 @@ export interface RemoteConfigSettings {
     minimumFetchIntervalMillis: number;
 }
 
+// Warning: (ae-incompatible-release-tags) The symbol "setCustomSignals" is marked as @public, but its signature references "CustomSignals" which is marked as @alpha
+//
+// @public (undocumented)
+export function setCustomSignals(remoteConfig: RemoteConfig, customSignals: CustomSignals): Promise<void>;
+
 // @public
 export function setLogLevel(remoteConfig: RemoteConfig, logLevel: LogLevel): void;
 

packages/remote-config-types/index.d.ts

@@ -173,6 +173,20 @@ export type FetchStatus = 'no-fetch-yet' | 'success' | 'failure' | 'throttle';
  */
 export type LogLevel = 'debug' | 'error' | 'silent';
 
+/**
+ * Defines the type for representing custom signals and their values.
+ * 
+ * <p>The values in CustomSignals must be one of the following types:
+ *
+ * <ul>
+ *   <li><code>string</code>
+ *   <li><code>number</code>
+ * </ul>
+ *
+ * @alpha
+ */
+export type CustomSignals = {[key: string]: string | number};
+
 declare module '@firebase/component' {
   interface NameServiceMapping {
     'remoteConfig-compat': RemoteConfig;

packages/remote-config/src/api.ts

@@ -17,6 +17,7 @@
 
 import { _getProvider, FirebaseApp, getApp } from '@firebase/app';
 import {
+  CustomSignals,
   LogLevel as RemoteConfigLogLevel,
   RemoteConfig,
   Value
@@ -108,6 +109,7 @@ export async function fetchConfig(remoteConfig: RemoteConfig): Promise<void> {
   // * it applies to all retries (like curl's max-time arg)
   // * it is consistent with the Fetch API's signal input
   const abortSignal = new RemoteConfigAbortSignal();
+  const customSignals = rc._storageCache.getCustomSignals();
 
   setTimeout(async () => {
     // Note a very low delay, eg < 10ms, can elapse before listeners are initialized.
@@ -118,7 +120,8 @@ export async function fetchConfig(remoteConfig: RemoteConfig): Promise<void> {
   try {
     await rc._client.fetch({
       cacheMaxAgeMillis: rc.settings.minimumFetchIntervalMillis,
-      signal: abortSignal
+      signal: abortSignal,
+      customSignals: rc._storageCache.getCustomSignals()
     });
 
     await rc._storageCache.setLastFetchStatus('success');
@@ -258,3 +261,9 @@ export function setLogLevel(
 function getAllKeys(obj1: {} = {}, obj2: {} = {}): string[] {
   return Object.keys({ ...obj1, ...obj2 });
 }
+
+export async function setCustomSignals(
+  remoteConfig: RemoteConfig, customSignals: CustomSignals): Promise<void> {
+  const rc = getModularInstance(remoteConfig) as RemoteConfigImpl;
+  return rc._storageCache.setCustomSignals(customSignals);
+}

packages/remote-config/src/client/remote_config_fetch_client.ts

@@ -15,6 +15,8 @@
  * limitations under the License.
  */
 
+import { CustomSignals } from "../public_types";
+
 /**
  * Defines a client, as in https://en.wikipedia.org/wiki/Client%E2%80%93server_model, for the
  * Remote Config server (https://firebase.google.com/docs/reference/remote-config/rest).
@@ -99,6 +101,13 @@ export interface FetchRequest {
    * <p>Comparable to passing `headers = { 'If-None-Match': <eTag> }` to the native Fetch API.
    */
   eTag?: string;
+
+
+  /** The custom signals stored for the app instance.
+   * 
+   * <p>Optional in case no custom signals are set for the instance.
+   */
+  customSignals?: CustomSignals;
 }
 
 /**

packages/remote-config/src/client/rest_client.ts

@@ -15,6 +15,7 @@
  * limitations under the License.
  */
 
+import { CustomSignals } from '../public_types';
 import {
   FetchResponse,
   RemoteConfigFetchClient,
@@ -41,6 +42,7 @@ interface FetchRequestBody {
   app_instance_id_token: string;
   app_id: string;
   language_code: string;
+  custom_signals?: CustomSignals;
   /* eslint-enable camelcase */
 }
 
@@ -92,7 +94,8 @@ export class RestClient implements RemoteConfigFetchClient {
       app_instance_id: installationId,
       app_instance_id_token: installationToken,
       app_id: this.appId,
-      language_code: getUserLanguage()
+      language_code: getUserLanguage(),
+      custom_signals: request.customSignals
       /* eslint-enable camelcase */
     };
 

packages/remote-config/src/public_types.ts

@@ -134,6 +134,20 @@ export type FetchStatus = 'no-fetch-yet' | 'success' | 'failure' | 'throttle';
  */
 export type LogLevel = 'debug' | 'error' | 'silent';
 
+/**
+ * Defines the type for representing custom signals and their values.
+ * 
+ * <p>The values in CustomSignals must be one of the following types:
+ *
+ * <ul>
+ *   <li><code>string</code>
+ *   <li><code>number</code>
+ * </ul>
+ *
+ * @alpha
+ */
+export type CustomSignals = {[key: string]: string | number};
+
 declare module '@firebase/component' {
   interface NameServiceMapping {
     'remote-config': RemoteConfig;

packages/remote-config/src/storage/storage.ts

@@ -15,7 +15,7 @@
  * limitations under the License.
  */
 
-import { FetchStatus } from '@firebase/remote-config-types';
+import { FetchStatus, CustomSignals } from '@firebase/remote-config-types';
 import {
   FetchResponse,
   FirebaseRemoteConfigObject
@@ -70,7 +70,8 @@ type ProjectNamespaceKeyFieldValue =
   | 'last_successful_fetch_timestamp_millis'
   | 'last_successful_fetch_response'
   | 'settings'
-  | 'throttle_metadata';
+  | 'throttle_metadata'
+  | 'custom_signals';
 
 // Visible for testing.
 export function openDatabase(): Promise<IDBDatabase> {
@@ -181,6 +182,53 @@ export class Storage {
     return this.delete('throttle_metadata');
   }
 
+  getCustomSignals(): Promise<CustomSignals | undefined> {
+    return this.get<CustomSignals>('custom_signals');
+  }
+
+  async setCustomSignals(customSignals: CustomSignals): Promise<void> {
+    const db = await this.openDbPromise;
+    return new Promise((resolve, reject) => {
+      const transaction = db.transaction([APP_NAMESPACE_STORE], 'readwrite');
+      const objectStore = transaction.objectStore(APP_NAMESPACE_STORE);
+      const compositeKey = this.createCompositeKey("custom_signals");
+      try {
+        const storedSignalsRequest = objectStore.get(compositeKey);
+        storedSignalsRequest.onerror = event => {
+          reject(toFirebaseError(event, ErrorCode.STORAGE_GET));
+        };
+        storedSignalsRequest.onsuccess = event => {
+          const storedSignals = (event.target as IDBRequest).result.value;
+          const combinedSignals = {
+            ...storedSignals,
+            ...customSignals
+          };
+          const signalsToUpdate = Object.fromEntries(Object.entries(combinedSignals).filter(([_, v]) => v !== null));
+          if (signalsToUpdate) {
+            const setSignalsRequest = objectStore.put({compositeKey, signalsToUpdate});
+            setSignalsRequest.onerror = event => {
+              reject(toFirebaseError(event, ErrorCode.STORAGE_SET));
+            };
+            setSignalsRequest.onsuccess = event => {
+              const result = (event.target as IDBRequest).result;
+              if (result) {
+                resolve(result.value);
+              } else {
+                resolve(undefined);
+              }
+            };
+          }
+        };
+      } catch (e) {
+        reject(
+          ERROR_FACTORY.create(ErrorCode.STORAGE_SET, {
+            originalErrorMessage: (e as Error)?.message
+          })
+        );
+      }
+    });
+  }
+
   async get<T>(key: ProjectNamespaceKeyFieldValue): Promise<T | undefined> {
     const db = await this.openDbPromise;
     return new Promise((resolve, reject) => {

packages/remote-config/src/storage/storage_cache.ts

@@ -15,7 +15,7 @@
  * limitations under the License.
  */
 
-import { FetchStatus } from '@firebase/remote-config-types';
+import { FetchStatus, CustomSignals } from '@firebase/remote-config-types';
 import { FirebaseRemoteConfigObject } from '../client/remote_config_fetch_client';
 import { Storage } from './storage';
 
@@ -31,6 +31,8 @@ export class StorageCache {
   private lastFetchStatus?: FetchStatus;
   private lastSuccessfulFetchTimestampMillis?: number;
   private activeConfig?: FirebaseRemoteConfigObject;
+  private customSignals?: CustomSignals;
+
 
   /**
    * Memory-only getters
@@ -47,6 +49,11 @@ export class StorageCache {
     return this.activeConfig;
   }
 
+  getCustomSignals(): CustomSignals | undefined {
+    return this.customSignals;
+  }
+
+
   /**
    * Read-ahead getter
    */
@@ -55,6 +62,7 @@ export class StorageCache {
     const lastSuccessfulFetchTimestampMillisPromise =
       this.storage.getLastSuccessfulFetchTimestampMillis();
     const activeConfigPromise = this.storage.getActiveConfig();
+    const customSignalsPromise = this.storage.getCustomSignals();
 
     // Note:
     // 1. we consistently check for undefined to avoid clobbering defined values
@@ -78,6 +86,11 @@ export class StorageCache {
     if (activeConfig) {
       this.activeConfig = activeConfig;
     }
+
+    const customSignals = await customSignalsPromise;
+    if (customSignals) {
+      this.customSignals = customSignals;
+    }
   }
 
   /**
@@ -99,4 +112,9 @@ export class StorageCache {
     this.activeConfig = activeConfig;
     return this.storage.setActiveConfig(activeConfig);
   }
+
+  setCustomSignals(customSignals: CustomSignals): Promise<void> {
+    this.customSignals = customSignals;
+    return this.storage.setCustomSignals(customSignals);
+  }
 }