Move validateCache logic outside SplitsCacheInLocal

Author: EmilianoSanchez

src/storages/inLocalStorage/SplitsCacheInLocal.ts

@@ -5,9 +5,7 @@ import { KeyBuilderCS } from '../KeyBuilderCS';
 import { ILogger } from '../../logger/types';
 import { LOG_PREFIX } from './constants';
 import { ISettings } from '../../types';
-import { getStorageHash } from '../KeyBuilder';
 import { setToArray } from '../../utils/lang/sets';
-import { DEFAULT_CACHE_EXPIRATION_IN_MILLIS } from '../../utils/constants/browser';
 
 /**
  * ISplitsCacheSync implementation that stores split definitions in browser LocalStorage.
@@ -26,42 +24,6 @@ export class SplitsCacheInLocal extends AbstractSplitsCacheSync {
     this.flagSetsFilter = settings.sync.__splitFiltersValidation.groupedFilters.bySet;
   }
 
-  /**
-   * Clean Splits cache if:
-   * - it has expired, i.e., its `lastUpdated` timestamp is older than the given `expirationTimestamp`
-   * - hash has changes, i.e., the SDK key, flags filter criteria or flags spec version was modified
-   */
-  public validateCache(settings: ISettings) {
-    // _checkExpiration
-    const expirationTimestamp = Date.now() - DEFAULT_CACHE_EXPIRATION_IN_MILLIS;
-    let value: string | number | null = localStorage.getItem(this.keys.buildLastUpdatedKey());
-    if (value !== null) {
-      value = parseInt(value, 10);
-      if (!isNaNNumber(value) && value < expirationTimestamp) this.clear();
-    }
-
-    // @TODO eventually remove `_checkFilterQuery`. Cache should be cleared at the storage level, reusing same logic than PluggableStorage
-    // _checkFilterQuery
-    const storageHashKey = this.keys.buildHashKey();
-    const storageHash = localStorage.getItem(storageHashKey);
-    const currentStorageHash = getStorageHash(settings);
-
-    if (storageHash !== currentStorageHash) {
-      this.log.info(LOG_PREFIX + 'SDK key, flags filter criteria or flags spec version was modified. Updating cache');
-      try {
-        // if there is cache, clear it
-        if (this.getChangeNumber() > -1) this.clear();
-
-        localStorage.setItem(storageHashKey, currentStorageHash);
-      } catch (e) {
-        this.log.error(LOG_PREFIX + e);
-      }
-    }
-    // if the filter didn't change, nothing is done
-
-    return this.getChangeNumber() > -1;
-  }
-
   private _decrementCount(key: string) {
     const count = toNumber(localStorage.getItem(key)) - 1;
     // @ts-expect-error

src/storages/inLocalStorage/__tests__/SplitsCacheInLocal.spec.ts

@@ -7,7 +7,6 @@ import { fullSettings } from '../../../utils/settingsValidation/__tests__/settin
 
 test('SPLIT CACHE / LocalStorage', () => {
   const cache = new SplitsCacheInLocal(fullSettings, new KeyBuilderCS('SPLITIO', 'user'));
-  cache.validateCache(fullSettings);
 
   cache.clear();
 
@@ -41,7 +40,6 @@ test('SPLIT CACHE / LocalStorage', () => {
 
 test('SPLIT CACHE / LocalStorage / Get Keys', () => {
   const cache = new SplitsCacheInLocal(fullSettings, new KeyBuilderCS('SPLITIO', 'user'));
-  cache.validateCache(fullSettings);
 
   cache.addSplit('lol1', something);
   cache.addSplit('lol2', somethingElse);
@@ -54,7 +52,6 @@ test('SPLIT CACHE / LocalStorage / Get Keys', () => {
 
 test('SPLIT CACHE / LocalStorage / Add Splits', () => {
   const cache = new SplitsCacheInLocal(fullSettings, new KeyBuilderCS('SPLITIO', 'user'));
-  cache.validateCache(fullSettings);
 
   cache.addSplits([
     ['lol1', something],
@@ -69,7 +66,6 @@ test('SPLIT CACHE / LocalStorage / Add Splits', () => {
 
 test('SPLIT CACHE / LocalStorage / trafficTypeExists and ttcache tests', () => {
   const cache = new SplitsCacheInLocal(fullSettings, new KeyBuilderCS('SPLITIO', 'user'));
-  cache.validateCache(fullSettings);
 
   cache.addSplits([ // loop of addSplit
     ['split1', splitWithUserTT],
@@ -108,7 +104,6 @@ test('SPLIT CACHE / LocalStorage / trafficTypeExists and ttcache tests', () => {
 
 test('SPLIT CACHE / LocalStorage / killLocally', () => {
   const cache = new SplitsCacheInLocal(fullSettings, new KeyBuilderCS('SPLITIO', 'user'));
-  cache.validateCache(fullSettings);
 
   cache.addSplit('lol1', something);
   cache.addSplit('lol2', somethingElse);
@@ -142,7 +137,6 @@ test('SPLIT CACHE / LocalStorage / killLocally', () => {
 
 test('SPLIT CACHE / LocalStorage / usesSegments', () => {
   const cache = new SplitsCacheInLocal(fullSettings, new KeyBuilderCS('SPLITIO', 'user'));
-  cache.validateCache(fullSettings);
 
   expect(cache.usesSegments()).toBe(true); // true initially, until data is synchronized
   cache.setChangeNumber(1); // to indicate that data has been synced.
@@ -174,7 +168,6 @@ test('SPLIT CACHE / LocalStorage / flag set cache tests', () => {
       }
     }
   }, new KeyBuilderCS('SPLITIO', 'user'));
-  cache.validateCache(fullSettings);
 
   const emptySet = new Set([]);
 
@@ -216,7 +209,6 @@ test('SPLIT CACHE / LocalStorage / flag set cache tests', () => {
 // if FlagSets are not defined, it should store all FlagSets in memory.
 test('SPLIT CACHE / LocalStorage / flag set cache tests without filters', () => {
   const cache = new SplitsCacheInLocal(fullSettings, new KeyBuilderCS('SPLITIO', 'user'));
-  cache.validateCache(fullSettings);
 
   const emptySet = new Set([]);
 
@@ -236,6 +228,5 @@ test('SPLIT CACHE / LocalStorage / flag set cache tests without filters', () =>
 
   // Validate that the feature flag cache is cleared when calling `clear` method
   cache.clear();
-  expect(localStorage.length).toBe(1); // only 'SPLITIO.hash' should remain in localStorage
-  expect(localStorage.key(0)).toBe('SPLITIO.hash');
+  expect(localStorage.length).toBe(0);
 });

src/storages/inLocalStorage/index.ts

@@ -13,6 +13,7 @@ import { DEBUG, NONE, STORAGE_LOCALSTORAGE } from '../../utils/constants';
 import { shouldRecordTelemetry, TelemetryCacheInMemory } from '../inMemory/TelemetryCacheInMemory';
 import { UniqueKeysCacheInMemoryCS } from '../inMemory/UniqueKeysCacheInMemoryCS';
 import { getMatching } from '../../utils/key';
+import { validateCache } from './validateCache';
 
 export interface InLocalStorageOptions {
   prefix?: string
@@ -51,9 +52,8 @@ export function InLocalStorage(options: InLocalStorageOptions = {}): IStorageSyn
       telemetry: shouldRecordTelemetry(params) ? new TelemetryCacheInMemory(splits, segments) : undefined,
       uniqueKeys: impressionsMode === NONE ? new UniqueKeysCacheInMemoryCS() : undefined,
 
-      // @TODO implement
       validateCache() {
-        return splits.validateCache(settings);
+        return validateCache(settings, keys, splits);
       },
 
       destroy() { },

src/storages/inLocalStorage/validateCache.ts

@@ -0,0 +1,43 @@
+import { ISettings } from '../../types';
+import { DEFAULT_CACHE_EXPIRATION_IN_MILLIS } from '../../utils/constants/browser';
+import { isNaNNumber } from '../../utils/lang';
+import { getStorageHash } from '../KeyBuilder';
+import { LOG_PREFIX } from './constants';
+import type { SplitsCacheInLocal } from './SplitsCacheInLocal';
+import { KeyBuilderCS } from '../KeyBuilderCS';
+
+/**
+ * Clean cache if:
+ * - it has expired, i.e., its `lastUpdated` timestamp is older than the given `expirationTimestamp`
+ * - hash has changed, i.e., the SDK key, flags filter criteria or flags spec version was modified
+ */
+export function validateCache(settings: ISettings, keys: KeyBuilderCS, splits: SplitsCacheInLocal): boolean {
+  const { log } = settings;
+
+  // Check expiration and clear cache if needed
+  const expirationTimestamp = Date.now() - DEFAULT_CACHE_EXPIRATION_IN_MILLIS;
+  let value: string | number | null = localStorage.getItem(keys.buildLastUpdatedKey());
+  if (value !== null) {
+    value = parseInt(value, 10);
+    if (!isNaNNumber(value) && value < expirationTimestamp) splits.clear();
+  }
+
+  // Check hash and clear cache if needed
+  const storageHashKey = keys.buildHashKey();
+  const storageHash = localStorage.getItem(storageHashKey);
+  const currentStorageHash = getStorageHash(settings);
+
+  if (storageHash !== currentStorageHash) {
+    log.info(LOG_PREFIX + 'SDK key, flags filter criteria or flags spec version was modified. Updating cache');
+    try {
+      if (splits.getChangeNumber() > -1) splits.clear();
+
+      localStorage.setItem(storageHashKey, currentStorageHash);
+    } catch (e) {
+      log.error(LOG_PREFIX + e);
+    }
+  }
+
+  // Check if the cache is ready
+  return splits.getChangeNumber() > -1;
+}

src/storages/pluggable/index.ts

@@ -92,7 +92,8 @@ export function PluggableStorage(options: PluggableStorageOptions): IStorageAsyn
     // Connects to wrapper and emits SDK_READY event on main client
     const connectPromise = wrapper.connect().then(() => {
       if (isSyncronizer) {
-        // In standalone or producer mode, clear storage if SDK key or feature flag filter has changed
+        // @TODO reuse InLocalStorage::validateCache logic
+        // In standalone or producer mode, clear storage if SDK key, flags filter criteria or flags spec version was modified
         return wrapper.get(keys.buildHashKey()).then((hash) => {
           const currentHash = getStorageHash(settings);
           if (hash !== currentHash) {