Comparable to the browser's Cache API for responses, but the Cache API requires a Service\n * Worker, which requires HTTPS, which would significantly complicate SDK installation. Also, the\n * Cache API doesn't support matching entries by time.\n */\nexport class CachingClient implements RemoteConfigFetchClient {\n constructor(\n private readonly client: RemoteConfigFetchClient,\n private readonly storage: Storage,\n private readonly storageCache: StorageCache,\n private readonly logger: Logger\n ) {}\n\n /**\n * Returns true if the age of the cached fetched configs is less than or equal to\n * {@link Settings#minimumFetchIntervalInSeconds}.\n *\n *
This is comparable to passing `headers = { 'Cache-Control': max-age Visible for testing.\n */\n isCachedDataFresh(\n cacheMaxAgeMillis: number,\n lastSuccessfulFetchTimestampMillis: number | undefined\n ): boolean {\n // Cache can only be fresh if it's populated.\n if (!lastSuccessfulFetchTimestampMillis) {\n this.logger.debug('Config fetch cache check. Cache unpopulated.');\n return false;\n }\n\n // Calculates age of cache entry.\n const cacheAgeMillis = Date.now() - lastSuccessfulFetchTimestampMillis;\n\n const isCachedDataFresh = cacheAgeMillis <= cacheMaxAgeMillis;\n\n this.logger.debug(\n 'Config fetch cache check.' +\n ` Cache age millis: ${cacheAgeMillis}.` +\n ` Cache max age millis (minimumFetchIntervalMillis setting): ${cacheMaxAgeMillis}.` +\n ` Is cache hit: ${isCachedDataFresh}.`\n );\n\n return isCachedDataFresh;\n }\n\n async fetch(request: FetchRequest): Promise Adapted from getUserLanguage in packages/auth/src/utils.js for TypeScript.\n *\n * Defers default language specification to server logic for consistency.\n *\n * @param navigatorLanguage Enables tests to override read-only {@link NavigatorLanguage}.\n */\nexport function getUserLanguage(\n navigatorLanguage: NavigatorLanguage = navigator\n): string {\n return (\n // Most reliable, but only supported in Chrome/Firefox.\n (navigatorLanguage.languages && navigatorLanguage.languages[0]) ||\n // Supported in most browsers, but returns the language of the browser\n // UI, not the language set in browser settings.\n navigatorLanguage.language\n // Polyfill otherwise.\n );\n}\n","/**\n * @license\n * Copyright 2019 Google LLC\n *\n * Licensed under the Apache License, Version 2.0 (the \"License\");\n * you may not use this file except in compliance with the License.\n * You may obtain a copy of the License at\n *\n * http://www.apache.org/licenses/LICENSE-2.0\n *\n * Unless required by applicable law or agreed to in writing, software\n * distributed under the License is distributed on an \"AS IS\" BASIS,\n * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n * See the License for the specific language governing permissions and\n * limitations under the License.\n */\n\nimport { FirebaseInstallations } from '@firebase/installations-types';\nimport {\n FetchResponse,\n RemoteConfigFetchClient,\n FirebaseRemoteConfigObject,\n FetchRequest\n} from './remote_config_fetch_client';\nimport { ERROR_FACTORY, ErrorCode } from '../errors';\nimport { getUserLanguage } from '../language';\n\n/**\n * Defines request body parameters required to call the fetch API:\n * https://firebase.google.com/docs/reference/remote-config/rest\n *\n * Not exported because this file encapsulates REST API specifics.\n *\n * Not passing User Properties because Analytics' source of truth on Web is server-side.\n */\ninterface FetchRequestBody {\n // Disables camelcase linting for request body params.\n /* eslint-disable camelcase*/\n sdk_version: string;\n app_instance_id: string;\n app_instance_id_token: string;\n app_id: string;\n language_code: string;\n /* eslint-enable camelcase */\n}\n\n/**\n * Implements the Client abstraction for the Remote Config REST API.\n */\nexport class RestClient implements RemoteConfigFetchClient {\n constructor(\n private readonly firebaseInstallations: FirebaseInstallations,\n private readonly sdkVersion: string,\n private readonly namespace: string,\n private readonly projectId: string,\n private readonly apiKey: string,\n private readonly appId: string\n ) {}\n\n /**\n * Fetches from the Remote Config REST API.\n *\n * @throws a {@link ErrorCode.FETCH_NETWORK} error if {@link GlobalFetch#fetch} can't\n * connect to the network.\n * @throws a {@link ErrorCode.FETCH_PARSE} error if {@link Response#json} can't parse the\n * fetch response.\n * @throws a {@link ErrorCode.FETCH_STATUS} error if the service returns an HTTP error status.\n */\n async fetch(request: FetchRequest): Promise Abstracts throttle, response cache and network implementation details.\n *\n * Modeled after the native {@link GlobalFetch} interface, which is relatively modern and\n * convenient, but simplified for Remote Config's use case.\n *\n * Disambiguation: {@link GlobalFetch} interface and the Remote Config service define \"fetch\"\n * methods. The RestClient uses the former to make HTTP calls. This interface abstracts the latter.\n */\nexport interface RemoteConfigFetchClient {\n /**\n * @throws if response status is not 200 or 304.\n */\n fetch(request: FetchRequest): Promise AbortController's AbortSignal conveniently decouples fetch timeout logic from other aspects\n * of networking, such as retries. Firebase doesn't use AbortController enough to justify a\n * polyfill recommendation, like we do with the Fetch API, but this minimal shim can easily be\n * swapped out if/when we do.\n */\nexport class RemoteConfigAbortSignal {\n listeners: Array<() => void> = [];\n addEventListener(listener: () => void): void {\n this.listeners.push(listener);\n }\n abort(): void {\n this.listeners.forEach(listener => listener());\n }\n}\n\n/**\n * Defines per-request inputs for the Remote Config fetch request.\n *\n * Modeled after the native {@link Request} interface, but simplified for Remote Config's\n * use case.\n */\nexport interface FetchRequest {\n /**\n * Uses cached config if it is younger than this age.\n *\n * Required because it's defined by settings, which always have a value.\n *\n * Comparable to passing `headers = { 'Cache-Control': max-age Required because all requests should be abortable.\n *\n * Comparable to the native\n * Fetch API's \"signal\" field on its request configuration object\n * https://fetch.spec.whatwg.org/#dom-requestinit-signal.\n *\n * Disambiguation: Remote Config commonly refers to API inputs as\n * \"signals\". See the private ConfigFetchRequestBody interface for those:\n * http://google3/firebase/remote_config/web/src/core/rest_client.ts?l=14&rcl=255515243.\n */\n signal: RemoteConfigAbortSignal;\n\n /**\n * The ETag header value from the last response.\n *\n * Optional in case this is the first request.\n *\n * Comparable to passing `headers = { 'If-None-Match': Modeled after the native {@link Response} interface, but simplified for Remote Config's\n * use case.\n */\nexport interface FetchResponse {\n /**\n * The HTTP status, which is useful for differentiating success responses with data from\n * those without.\n *\n * {@link RemoteConfigClient} is modeled after the native {@link GlobalFetch} interface, so\n * HTTP status is first-class.\n *\n * Disambiguation: the fetch response returns a legacy \"state\" value that is redundant with the\n * HTTP status code. The former is normalized into the latter.\n */\n status: number;\n\n /**\n * Defines the ETag response header value.\n *\n * Only defined for 200 and 304 responses.\n */\n eTag?: string;\n\n /**\n * Defines the map of parameters returned as \"entries\" in the fetch response body.\n *\n * Only defined for 200 responses.\n */\n config?: FirebaseRemoteConfigObject;\n\n // Note: we're not extracting experiment metadata until\n // ABT and Analytics have Web SDKs.\n}\n","/**\n * @license\n * Copyright 2019 Google LLC\n *\n * Licensed under the Apache License, Version 2.0 (the \"License\");\n * you may not use this file except in compliance with the License.\n * You may obtain a copy of the License at\n *\n * http://www.apache.org/licenses/LICENSE-2.0\n *\n * Unless required by applicable law or agreed to in writing, software\n * distributed under the License is distributed on an \"AS IS\" BASIS,\n * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n * See the License for the specific language governing permissions and\n * limitations under the License.\n */\n\nimport { Value as ValueType, ValueSource } from '@firebase/remote-config-types';\n\nconst DEFAULT_VALUE_FOR_BOOLEAN = false;\nconst DEFAULT_VALUE_FOR_STRING = '';\nconst DEFAULT_VALUE_FOR_NUMBER = 0;\n\nconst BOOLEAN_TRUTHY_VALUES = ['1', 'true', 't', 'yes', 'y', 'on'];\n\nexport class Value implements ValueType {\n constructor(\n private readonly _source: ValueSource,\n private readonly _value: string = DEFAULT_VALUE_FOR_STRING\n ) {}\n\n asString(): string {\n return this._value;\n }\n\n asBoolean(): boolean {\n if (this._source === 'static') {\n return DEFAULT_VALUE_FOR_BOOLEAN;\n }\n return BOOLEAN_TRUTHY_VALUES.indexOf(this._value.toLowerCase()) >= 0;\n }\n\n asNumber(): number {\n if (this._source === 'static') {\n return DEFAULT_VALUE_FOR_NUMBER;\n }\n let num = Number(this._value);\n if (isNaN(num)) {\n num = DEFAULT_VALUE_FOR_NUMBER;\n }\n return num;\n }\n\n getSource(): ValueSource {\n return this._source;\n }\n}\n","/**\n * @license\n * Copyright 2019 Google LLC\n *\n * Licensed under the Apache License, Version 2.0 (the \"License\");\n * you may not use this file except in compliance with the License.\n * You may obtain a copy of the License at\n *\n * http://www.apache.org/licenses/LICENSE-2.0\n *\n * Unless required by applicable law or agreed to in writing, software\n * distributed under the License is distributed on an \"AS IS\" BASIS,\n * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n * See the License for the specific language governing permissions and\n * limitations under the License.\n */\n\nimport { FirebaseApp } from '@firebase/app-types';\nimport {\n RemoteConfig as RemoteConfigType,\n FetchStatus,\n Settings,\n Value as ValueType,\n LogLevel as RemoteConfigLogLevel\n} from '@firebase/remote-config-types';\nimport { StorageCache } from './storage/storage_cache';\nimport {\n RemoteConfigFetchClient,\n RemoteConfigAbortSignal\n} from './client/remote_config_fetch_client';\nimport { Value } from './value';\nimport { ErrorCode, hasErrorCode } from './errors';\nimport { Storage } from './storage/storage';\nimport { Logger, LogLevel as FirebaseLogLevel } from '@firebase/logger';\n\nconst DEFAULT_FETCH_TIMEOUT_MILLIS = 60 * 1000; // One minute\nconst DEFAULT_CACHE_MAX_AGE_MILLIS = 12 * 60 * 60 * 1000; // Twelve hours.\n\n/**\n * Encapsulates business logic mapping network and storage dependencies to the public SDK API.\n *\n * See {@link https://github.com/FirebasePrivate/firebase-js-sdk/blob/master/packages/firebase/index.d.ts|interface documentation} for method descriptions.\n */\nexport class RemoteConfig implements RemoteConfigType {\n // Tracks completion of initialization promise.\n private _isInitializationComplete = false;\n\n // De-duplicates initialization calls.\n private _initializePromise?: Promise Aborting after the request completes is a no-op, so we don't need a\n // corresponding clearTimeout.\n //\n // Locating abort logic here because:\n // * it uses a developer setting (timeout)\n // * it applies to all retries (like curl's max-time arg)\n // * it is consistent with the Fetch API's signal input\n const abortSignal = new RemoteConfigAbortSignal();\n\n setTimeout(async () => {\n // Note a very low delay, eg < 10ms, can elapse before listeners are initialized.\n abortSignal.abort();\n }, this.settings.fetchTimeoutMillis);\n\n // Catches *all* errors thrown by client so status can be set consistently.\n try {\n await this._client.fetch({\n cacheMaxAgeMillis: this.settings.minimumFetchIntervalMillis,\n signal: abortSignal\n });\n\n await this._storageCache.setLastFetchStatus('success');\n } catch (e) {\n const lastFetchStatus = hasErrorCode(e, ErrorCode.FETCH_THROTTLE)\n ? 'throttle'\n : 'failure';\n await this._storageCache.setLastFetchStatus(lastFetchStatus);\n throw e;\n }\n }\n\n async fetchAndActivate(): Promise The Remote Config SDK can be used with multiple app installations, and each app can interact\n * with multiple namespaces, so this store uses app (ID + name) and namespace as common parent keys\n * for a set of key-value pairs. See {@link Storage#createCompositeKey}.\n *\n * Visible for testing.\n */\nexport const APP_NAMESPACE_STORE = 'app_namespace_store';\n\nconst DB_NAME = 'firebase_remote_config';\nconst DB_VERSION = 1;\n\n/**\n * Encapsulates metadata concerning throttled fetch requests.\n */\nexport interface ThrottleMetadata {\n // The number of times fetch has backed off. Used for resuming backoff after a timeout.\n backoffCount: number;\n // The Unix timestamp in milliseconds when callers can retry a request.\n throttleEndTimeMillis: number;\n}\n\n/**\n * Provides type-safety for the \"key\" field used by {@link APP_NAMESPACE_STORE}.\n *\n * This seems like a small price to avoid potentially subtle bugs caused by a typo.\n */\ntype ProjectNamespaceKeyFieldValue =\n | 'active_config'\n | 'active_config_etag'\n | 'last_fetch_status'\n | 'last_successful_fetch_timestamp_millis'\n | 'last_successful_fetch_response'\n | 'settings'\n | 'throttle_metadata';\n\n// Visible for testing.\nexport function openDatabase(): Promise Visible for testing\n */\nexport const MAX_VALUE_MILLIS = 4 * 60 * 60 * 1000; // Four hours, like iOS and Android.\n\n/**\n * The percentage of backoff time to randomize by.\n * See\n * http://go/safe-client-behavior#step-1-determine-the-appropriate-retry-interval-to-handle-spike-traffic\n * for context.\n *\n * Visible for testing\n */\nexport const RANDOM_FACTOR = 0.5;\n\n/**\n * Based on the backoff method from\n * https://github.com/google/closure-library/blob/master/closure/goog/math/exponentialbackoff.js.\n * Extracted here so we don't need to pass metadata and a stateful ExponentialBackoff object around.\n */\nexport function calculateBackoffMillis(backoffCount: number): number {\n // Calculates an exponentially increasing value.\n // Deviation: calculates value from count and a constant interval, so we only need to save value\n // and count to restore state.\n const currBaseValue =\n INTERVAL_MILLIS * Math.pow(BACKOFF_FACTOR, backoffCount);\n\n // A random \"fuzz\" to avoid waves of retries.\n // Deviation: randomFactor is required.\n const randomWait = Math.round(\n // A fraction of the backoff value to add/subtract.\n // Deviation: changes multiplication order to improve readability.\n RANDOM_FACTOR *\n currBaseValue *\n // A random float (rounded to int by Math.round above) in the range [-1, 1]. Determines\n // if we add or subtract.\n (Math.random() - 0.5) *\n 2\n );\n\n // Limits backoff to max to avoid effectively permanent backoff.\n return Math.min(MAX_VALUE_MILLIS, currBaseValue + randomWait);\n}\n","/**\n * @license\n * Copyright 2019 Google LLC\n *\n * Licensed under the Apache License, Version 2.0 (the \"License\");\n * you may not use this file except in compliance with the License.\n * You may obtain a copy of the License at\n *\n * http://www.apache.org/licenses/LICENSE-2.0\n *\n * Unless required by applicable law or agreed to in writing, software\n * distributed under the License is distributed on an \"AS IS\" BASIS,\n * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n * See the License for the specific language governing permissions and\n * limitations under the License.\n */\n\nimport {\n RemoteConfigAbortSignal,\n RemoteConfigFetchClient,\n FetchResponse,\n FetchRequest\n} from './remote_config_fetch_client';\nimport { ThrottleMetadata, Storage } from '../storage/storage';\nimport { calculateBackoffMillis } from './exponential_backoff';\nimport { ErrorCode, ERROR_FACTORY } from '../errors';\nimport { FirebaseError } from '@firebase/util';\n\n/**\n * Supports waiting on a backoff by:\n *\n * Visible for testing.\n */\nexport function setAbortableTimeout(\n signal: RemoteConfigAbortSignal,\n throttleEndTimeMillis: number\n): Promise Comparable to CachingClient, but uses backoff logic instead of cache max age and doesn't cache\n * responses (because the SDK has no use for error responses).\n */\nexport class RetryingClient implements RemoteConfigFetchClient {\n constructor(\n private readonly client: RemoteConfigFetchClient,\n private readonly storage: Storage\n ) {}\n\n async fetch(request: FetchRequest): Promise\n *
\n *\n *