[cache-adapter-local-memory] export classes

* v0.24.0

* changelog

CHANGELOG.md

@@ -3,6 +3,30 @@
 All notable changes to this project will be documented in this file.
 See [Conventional Commits](https://conventionalcommits.org) for commit guidelines.
 
+# [0.24.0](https://github.com/expo/entity/compare/v0.23.0...v0.24.0) (2022-02-16)
+
+
+### Features
+
+* add local memory cache package  ([#158](https://github.com/expo/entity/issues/158)) ([85d3575](https://github.com/expo/entity/commit/85d35752fa0919a62efb776a762a6829e83ca7af))
+
+### Chores
+
+* Refactor cachers to use an abstract class and interface  ([#157](https://github.com/expo/entity/pull/157)) 
+
+
+
+
+
+# [0.23.0](https://github.com/expo/entity/compare/v0.22.0...v0.23.0) (2022-02-09)
+
+### Breaking changes
+
+* Move data transforming responsibilities to the CacheAdapter instead of the ReadThroughEntityCache. Affects any classes extending the EntityCacheAdapter and relying on the transformation behavior of the ReadThroughEntityCache. ([#153](https://github.com/expo/entity/pull/153))
+
+
+
+
 # [0.22.0](https://github.com/expo/entity/compare/v0.21.0...v0.22.0) (2022-02-04)
 
 

lerna.json

@@ -4,5 +4,5 @@
   ],
   "npmClient": "yarn",
   "useWorkspaces": true,
-  "version": "0.22.0"
+  "version": "0.24.0"
 }

package.json

@@ -18,6 +18,7 @@
   "devDependencies": {
     "@expo/entity": "file:packages/entity",
     "@expo/results": "^1.0.0",
+    "@types/lru-cache": "^5.1.1",
     "@types/invariant": "^2.2.33",
     "@types/ioredis": "^4.26.4",
     "@types/jest": "^26.0.10",
@@ -43,6 +44,7 @@
   },
   "dependencies": {
     "@expo/entity": "file:packages/entity",
+    "@expo/entity-cache-adapter-local-memory": "file:packages/entity-cache-adapter-local-memory",
     "@expo/entity-cache-adapter-redis": "file:packages/entity-cache-adapter-redis",
     "@expo/entity-database-adapter-knex": "file:packages/entity-database-adapter-knex",
     "@expo/entity-secondary-cache-redis": "file:packages/entity-secondary-cache-redis",

packages/entity-cache-adapter-local-memory/CHANGELOG.md

@@ -0,0 +1,11 @@
+# Change Log
+
+All notable changes to this project will be documented in this file.
+See [Conventional Commits](https://conventionalcommits.org) for commit guidelines.
+
+# [0.24.0](https://github.com/expo/entity/compare/v0.23.0...v0.24.0) (2022-02-16)
+
+
+### Features
+
+* add local memory cache package  ([#158](https://github.com/expo/entity/issues/158)) ([85d3575](https://github.com/expo/entity/commit/85d35752fa0919a62efb776a762a6829e83ca7af))

packages/entity-cache-adapter-local-memory/README.md

@@ -0,0 +1,44 @@
+# `@expo/entity-cache-adapter-local-memory`
+
+Cross-request [LRU](https://github.com/isaacs/node-lru-cache) cache adapter for `@expo/entity`. Use
+this cache with caution - it is nonstandard. The cache is shared between requests in the node process.
+
+## Why NOT use this cache
+
+Because this is an in-memory cache, cross-box invalidation is not possible. Do not use this cache
+if you have the following use cases:
+
+- The objects stored have high mutability
+- Reading a stale object from the cache is not acceptable in your application
+- Cross-box invalidation is not possible
+
+## Typical use cases
+
+If your application sees many requests fetching the same objects, you can save a trip to your cache
+cluster and backing datastore by using this in-memory cache. Here are some good use cases:
+
+- The objects stored are mostly immutable
+- You have a low TTL setting in your cache
+
+## Usage
+
+During `EntityCompanionProvider` instantiation:
+
+```typescript
+export const createDefaultEntityCompanionProvider = (
+  metricsAdapter: IEntityMetricsAdapter = new NoOpEntityMetricsAdapter()
+): EntityCompanionProvider => {
+  return new EntityCompanionProvider(
+    metricsAdapter,
+    {
+      ...
+    },
+    {
+      ['local-memory']: {
+        cacheAdapterProvider: new LocalMemoryCacheAdapterProvider.getProvider(),
+      },
+    }
+  );
+};
+
+```

packages/entity-cache-adapter-local-memory/package.json

@@ -0,0 +1,38 @@
+{
+  "name": "@expo/entity-cache-adapter-local-memory",
+  "version": "0.24.0",
+  "description": "Cross-request local memory cache adapter for @expo/entity",
+  "files": [
+    "build",
+    "src"
+  ],
+  "main": "build/index.js",
+  "types": "build/index.d.ts",
+  "scripts": {
+    "tsc": "tsc",
+    "clean": "rm -rf build coverage coverage-integration",
+    "lint": "eslint src",
+    "lint-fix": "eslint src --fix",
+    "test": "jest --rootDir . --config ../../resources/jest.config.js",
+    "integration": "../../resources/run-with-docker yarn integration-no-setup",
+    "integration-no-setup": "jest --config ../../resources/jest-integration.config.js --rootDir . --runInBand --passWithNoTests",
+    "barrelsby": "barrelsby --directory src --location top --exclude tests__ --singleQuotes --exportDefault --delete"
+  },
+  "engines": {
+    "node": ">=12"
+  },
+  "keywords": [
+    "entity"
+  ],
+  "author": "Expo",
+  "license": "MIT",
+  "peerDependencies": {
+    "@expo/entity": "*"
+  },
+  "dependencies": {
+    "lru-cache": "^7.3.1"
+  },
+  "devDependencies": {
+    "@expo/entity": "^0.24.0"
+  }
+}

packages/entity-cache-adapter-local-memory/src/GenericLocalMemoryCacher.ts

@@ -0,0 +1,154 @@
+import { CacheLoadResult, CacheStatus, IEntityGenericCacher } from '@expo/entity';
+import LRUCache from 'lru-cache';
+
+// Sentinel value we store in local memory to negatively cache a database miss.
+// The sentinel value is distinct from any (positively) cached value.
+export const DOES_NOT_EXIST_LOCAL_MEMORY_CACHE = Symbol('doesNotExist');
+type LocalMemoryCacheValue<TFields> = Readonly<TFields> | typeof DOES_NOT_EXIST_LOCAL_MEMORY_CACHE;
+export type LocalMemoryCache<TFields> = LRUCache<string, LocalMemoryCacheValue<TFields>>;
+
+type LRUCacheOptionsV7<K, V> = {
+  /**
+   * the number of most recently used items to keep.
+   * note that we may store fewer items than this if maxSize is hit.
+   */
+  max: number;
+
+  /**
+   * if you wish to track item size, you must provide a maxSize
+   * note that we still will only keep up to max *actual items*,
+   * so size tracking may cause fewer than max items to be stored.
+   * At the extreme, a single item of maxSize size will cause everything
+   * else in the cache to be dropped when it is added.  Use with caution!
+   * Note also that size tracking can negatively impact performance,
+   * though for most cases, only minimally.
+   */
+
+  maxSize?: number;
+
+  /**
+   * function to calculate size of items.  useful if storing strings or
+   * buffers or other items where memory size depends on the object itself.
+   * also note that oversized items do NOT immediately get dropped from
+   * the cache, though they will cause faster turnover in the storage.
+   */
+  sizeCalculation?: (value: V, key: K) => number;
+
+  /**
+   * function to call when the item is removed from the cache
+   * Note that using this can negatively impact performance.
+   */
+  dispose?: (value: V, key: K) => void;
+
+  /**
+   * max time to live for items before they are considered stale
+   * note that stale items are NOT preemptively removed by default,
+   * and MAY live in the cache, contributing to its LRU max, long after
+   * they have expired.
+   * Also, as this cache is optimized for LRU/MRU operations, some of
+   * the staleness/TTL checks will reduce performance, as they will incur
+   * overhead by deleting items.
+   * Must be a positive integer in ms, defaults to 0, which means "no TTL"
+   */
+  ttl?: number;
+
+  /**
+   * return stale items from cache.get() before disposing of them
+   * boolean, default false
+   */
+  allowStale?: boolean;
+
+  /**
+   * update the age of items on cache.get(), renewing their TTL
+   * boolean, default false
+   */
+  updateAgeOnGet?: boolean;
+
+  /**
+   * update the age of items on cache.has(), renewing their TTL
+   * boolean, default false
+   */
+  updateAgeOnHas?: boolean;
+
+  /**
+   * update the "recently-used"-ness of items on cache.has()
+   * boolean, default false
+   */
+  updateRecencyOnHas?: boolean;
+};
+
+export default class GenericLocalMemoryCacher<TFields> implements IEntityGenericCacher<TFields> {
+  constructor(private readonly localMemoryCache: LocalMemoryCache<TFields>) {}
+
+  static createLRUCache<TFields>(
+    options: { maxSize?: number; ttlSeconds?: number } = {}
+  ): LocalMemoryCache<TFields> {
+    const DEFAULT_LRU_CACHE_MAX_AGE_SECONDS = 10;
+    const DEFAULT_LRU_CACHE_SIZE = 10000;
+    const maxAgeSeconds = options.ttlSeconds ?? DEFAULT_LRU_CACHE_MAX_AGE_SECONDS;
+    const lruCacheOptions: LRUCacheOptionsV7<string, TFields> = {
+      max: options.maxSize ?? DEFAULT_LRU_CACHE_SIZE,
+      sizeCalculation: (value: LocalMemoryCacheValue<TFields>) =>
+        value === DOES_NOT_EXIST_LOCAL_MEMORY_CACHE ? 0 : 1,
+      ttl: maxAgeSeconds * 1000, // convert to ms
+    };
+    return new LRUCache<string, LocalMemoryCacheValue<TFields>>(lruCacheOptions as any);
+  }
+
+  static createNoOpCache<TFields>(): LocalMemoryCache<TFields> {
+    return new LRUCache<string, LocalMemoryCacheValue<TFields>>({
+      max: 0,
+      maxAge: -1,
+    });
+  }
+
+  public async loadManyAsync(
+    keys: readonly string[]
+  ): Promise<ReadonlyMap<string, CacheLoadResult<TFields>>> {
+    const cacheResults = new Map<string, CacheLoadResult<TFields>>();
+    for (const key of keys) {
+      const cacheResult = this.localMemoryCache.get(key);
+      if (cacheResult === DOES_NOT_EXIST_LOCAL_MEMORY_CACHE) {
+        cacheResults.set(key, {
+          status: CacheStatus.NEGATIVE,
+        });
+      } else if (cacheResult) {
+        cacheResults.set(key, {
+          status: CacheStatus.HIT,
+          item: cacheResult as unknown as TFields,
+        });
+      } else {
+        cacheResults.set(key, {
+          status: CacheStatus.MISS,
+        });
+      }
+    }
+    return cacheResults;
+  }
+
+  public async cacheManyAsync(objectMap: ReadonlyMap<string, Readonly<TFields>>): Promise<void> {
+    for (const [key, item] of objectMap) {
+      this.localMemoryCache.set(key, item);
+    }
+  }
+
+  public async cacheDBMissesAsync(keys: readonly string[]): Promise<void> {
+    for (const key of keys) {
+      this.localMemoryCache.set(key, DOES_NOT_EXIST_LOCAL_MEMORY_CACHE);
+    }
+  }
+
+  public async invalidateManyAsync(keys: readonly string[]): Promise<void> {
+    for (const key of keys) {
+      this.localMemoryCache.del(key);
+    }
+  }
+
+  public makeCacheKey(parts: string[]): string {
+    const delimiter = ':';
+    const escapedParts = parts.map((part) =>
+      part.replace('\\', '\\\\').replace(delimiter, `\\${delimiter}`)
+    );
+    return escapedParts.join(delimiter);
+  }
+}

packages/entity-cache-adapter-local-memory/src/LocalMemoryCacheAdapter.ts

@@ -0,0 +1,80 @@
+import { EntityCacheAdapter, CacheLoadResult, EntityConfiguration, mapKeys } from '@expo/entity';
+import invariant from 'invariant';
+
+import GenericLocalMemoryCacher, { LocalMemoryCache } from './GenericLocalMemoryCacher';
+
+export default class LocalMemoryCacheAdapter<TFields> extends EntityCacheAdapter<TFields> {
+  private readonly genericLocalMemoryCacher: GenericLocalMemoryCacher<TFields>;
+
+  constructor(
+    entityConfiguration: EntityConfiguration<TFields>,
+    localMemoryCache: LocalMemoryCache<TFields>
+  ) {
+    super(entityConfiguration);
+    this.genericLocalMemoryCacher = new GenericLocalMemoryCacher(localMemoryCache);
+  }
+
+  public async loadManyAsync<N extends keyof TFields>(
+    fieldName: N,
+    fieldValues: readonly NonNullable<TFields[N]>[]
+  ): Promise<ReadonlyMap<NonNullable<TFields[N]>, CacheLoadResult<TFields>>> {
+    const localMemoryCacheKeyToFieldValueMapping = new Map(
+      fieldValues.map((fieldValue) => [this.makeCacheKey(fieldName, fieldValue), fieldValue])
+    );
+    const cacheResults = await this.genericLocalMemoryCacher.loadManyAsync(
+      Array.from(localMemoryCacheKeyToFieldValueMapping.keys())
+    );
+
+    return mapKeys(cacheResults, (cacheKey) => {
+      const fieldValue = localMemoryCacheKeyToFieldValueMapping.get(cacheKey);
+      invariant(
+        fieldValue !== undefined,
+        'Unspecified cache key %s returned from generic local memory cacher',
+        cacheKey
+      );
+      return fieldValue;
+    });
+  }
+
+  public async cacheManyAsync<N extends keyof TFields>(
+    fieldName: N,
+    objectMap: ReadonlyMap<NonNullable<TFields[N]>, Readonly<TFields>>
+  ): Promise<void> {
+    await this.genericLocalMemoryCacher.cacheManyAsync(
+      mapKeys(objectMap, (fieldValue) => this.makeCacheKey(fieldName, fieldValue))
+    );
+  }
+
+  public async cacheDBMissesAsync<N extends keyof TFields>(
+    fieldName: N,
+    fieldValues: readonly NonNullable<TFields[N]>[]
+  ): Promise<void> {
+    await this.genericLocalMemoryCacher.cacheDBMissesAsync(
+      fieldValues.map((fieldValue) => this.makeCacheKey(fieldName, fieldValue))
+    );
+  }
+
+  public async invalidateManyAsync<N extends keyof TFields>(
+    fieldName: N,
+    fieldValues: readonly NonNullable<TFields[N]>[]
+  ): Promise<void> {
+    await this.genericLocalMemoryCacher.invalidateManyAsync(
+      fieldValues.map((fieldValue) => this.makeCacheKey(fieldName, fieldValue))
+    );
+  }
+
+  private makeCacheKey<N extends keyof TFields>(
+    fieldName: N,
+    fieldValue: NonNullable<TFields[N]>
+  ): string {
+    const columnName = this.entityConfiguration.entityToDBFieldsKeyMapping.get(fieldName);
+    invariant(columnName, `database field mapping missing for ${fieldName}`);
+    const parts = [
+      this.entityConfiguration.tableName,
+      `${this.entityConfiguration.cacheKeyVersion}`,
+      columnName,
+      String(fieldValue),
+    ];
+    return this.genericLocalMemoryCacher.makeCacheKey(parts);
+  }
+}

packages/entity-cache-adapter-local-memory/src/LocalMemoryCacheAdapterProvider.ts

@@ -0,0 +1,45 @@
+import {
+  computeIfAbsent,
+  EntityCacheAdapter,
+  EntityConfiguration,
+  IEntityCacheAdapterProvider,
+} from '@expo/entity';
+
+import GenericLocalMemoryCacher, { LocalMemoryCache } from './GenericLocalMemoryCacher';
+import LocalMemoryCacheAdapter from './LocalMemoryCacheAdapter';
+
+export default class LocalMemoryCacheAdapterProvider implements IEntityCacheAdapterProvider {
+  // local memory cache adapters should be shared/reused across requests
+  static localMemoryCacheAdapterMap = new Map<string, LocalMemoryCacheAdapter<any>>();
+
+  static getNoOpProvider(): IEntityCacheAdapterProvider {
+    return new LocalMemoryCacheAdapterProvider(<TFields>() =>
+      GenericLocalMemoryCacher.createNoOpCache<TFields>()
+    );
+  }
+
+  static getProvider(
+    options: { maxSize?: number; ttlSeconds?: number } = {}
+  ): IEntityCacheAdapterProvider {
+    return new LocalMemoryCacheAdapterProvider(<TFields>() =>
+      GenericLocalMemoryCacher.createLRUCache<TFields>(options)
+    );
+  }
+
+  private constructor(
+    private readonly localMemoryCacheCreator: <TFields>() => LocalMemoryCache<TFields>
+  ) {}
+
+  public getCacheAdapter<TFields>(
+    entityConfiguration: EntityConfiguration<TFields>
+  ): EntityCacheAdapter<TFields> {
+    return computeIfAbsent(
+      LocalMemoryCacheAdapterProvider.localMemoryCacheAdapterMap,
+      entityConfiguration.tableName,
+      () => {
+        const localMemoryCache = this.localMemoryCacheCreator<TFields>();
+        return new LocalMemoryCacheAdapter(entityConfiguration, localMemoryCache);
+      }
+    );
+  }
+}

packages/entity-cache-adapter-local-memory/src/__integration-tests__/LocalMemoryCacheAdapter-integration-test.ts

@@ -0,0 +1,180 @@
+import { CacheStatus, ViewerContext } from '@expo/entity';
+import { v4 as uuidv4 } from 'uuid';
+
+import GenericLocalMemoryCacher from '../GenericLocalMemoryCacher';
+import LocalMemoryCacheAdapter from '../LocalMemoryCacheAdapter';
+import { LocalMemoryCacheAdapterProvider } from '../LocalMemoryCacheAdapterProvider';
+import LocalMemoryTestEntity from '../testfixtures/LocalMemoryTestEntity';
+import {
+  createLocalMemoryIntegrationTestEntityCompanionProvider,
+  createNoopLocalMemoryIntegrationTestEntityCompanionProvider,
+} from '../testfixtures/createLocalMemoryIntegrationTestEntityCompanionProvider';
+
+class TestViewerContext extends ViewerContext {}
+
+describe(LocalMemoryCacheAdapter, () => {
+  beforeEach(async () => {
+    LocalMemoryCacheAdapterProvider.localMemoryCacheAdapterMap.clear();
+  });
+
+  it('has correct caching behavior', async () => {
+    const viewerContext = new TestViewerContext(
+      createLocalMemoryIntegrationTestEntityCompanionProvider()
+    );
+    const cacheAdapter = viewerContext.entityCompanionProvider.getCompanionForEntity(
+      LocalMemoryTestEntity,
+      LocalMemoryTestEntity.getCompanionDefinition()
+    )['tableDataCoordinator']['cacheAdapter'];
+    const cacheKeyMaker = cacheAdapter['makeCacheKey'].bind(cacheAdapter);
+
+    const date = new Date();
+    const entity1Created = await LocalMemoryTestEntity.creator(viewerContext)
+      .setField('name', 'blah')
+      .setField('dateField', date)
+      .enforceCreateAsync();
+
+    // loading an entity should put it in cache
+    const entity1 = await LocalMemoryTestEntity.loader(viewerContext)
+      .enforcing()
+      .loadByIDAsync(entity1Created.getID());
+
+    const entitySpecificGenericCacher =
+      LocalMemoryCacheAdapterProvider.localMemoryCacheAdapterMap.get(
+        LocalMemoryTestEntity.getCompanionDefinition().entityConfiguration.tableName
+      )!['genericLocalMemoryCacher'];
+    const cachedResult = await entitySpecificGenericCacher.loadManyAsync([
+      cacheKeyMaker('id', entity1.getID()),
+    ]);
+    const cachedValue = cachedResult.get(cacheKeyMaker('id', entity1.getID()))!;
+    expect(cachedValue).toMatchObject({
+      status: CacheStatus.HIT,
+      item: {
+        id: entity1.getID(),
+        name: 'blah',
+        dateField: date,
+      },
+    });
+
+    // simulate non existent db fetch, should write negative result ('') to cache
+    const nonExistentId = uuidv4();
+
+    const entityNonExistentResult = await LocalMemoryTestEntity.loader(viewerContext).loadByIDAsync(
+      nonExistentId
+    );
+    expect(entityNonExistentResult.ok).toBe(false);
+
+    const nonExistentCachedResult = await entitySpecificGenericCacher.loadManyAsync([
+      cacheKeyMaker('id', nonExistentId),
+    ]);
+    expect(nonExistentCachedResult.get(cacheKeyMaker('id', nonExistentId))).toMatchObject({
+      status: CacheStatus.NEGATIVE,
+    });
+
+    // load again through entities framework to ensure it reads negative result
+    const entityNonExistentResult2 = await LocalMemoryTestEntity.loader(
+      viewerContext
+    ).loadByIDAsync(nonExistentId);
+    expect(entityNonExistentResult2.ok).toBe(false);
+
+    // invalidate from cache to ensure it invalidates correctly
+    await LocalMemoryTestEntity.loader(viewerContext).invalidateFieldsAsync(entity1.getAllFields());
+    const cachedResultMiss = await entitySpecificGenericCacher.loadManyAsync([
+      cacheKeyMaker('id', entity1.getID()),
+    ]);
+    const cachedValueMiss = cachedResultMiss.get(cacheKeyMaker('id', entity1.getID()));
+    expect(cachedValueMiss).toMatchObject({ status: CacheStatus.MISS });
+  });
+
+  it('shares the cache between different requests', async () => {
+    const genericLocalMemoryCacherLoadManySpy = jest.spyOn(
+      GenericLocalMemoryCacher.prototype as unknown as any,
+      'loadManyAsync'
+    );
+    const viewerContext = new TestViewerContext(
+      createLocalMemoryIntegrationTestEntityCompanionProvider()
+    );
+
+    const date = new Date();
+    const entity1Created = await LocalMemoryTestEntity.creator(viewerContext)
+      .setField('name', 'blah')
+      .setField('dateField', date)
+      .enforceCreateAsync();
+
+    // loading an entity should put it in cache
+    await LocalMemoryTestEntity.loader(viewerContext)
+      .enforcing()
+      .loadByIDAsync(entity1Created.getID());
+
+    // load entity with a different request
+    const viewerContext2 = new TestViewerContext(
+      createLocalMemoryIntegrationTestEntityCompanionProvider()
+    );
+    const entity1WithVc2 = await LocalMemoryTestEntity.loader(viewerContext2)
+      .enforcing()
+      .loadByIDAsync(entity1Created.getID());
+
+    const cacheAdapter = viewerContext.entityCompanionProvider.getCompanionForEntity(
+      LocalMemoryTestEntity,
+      LocalMemoryTestEntity.getCompanionDefinition()
+    )['tableDataCoordinator']['cacheAdapter'];
+    const cacheKeyMaker = cacheAdapter['makeCacheKey'].bind(cacheAdapter);
+    expect(entity1WithVc2.getAllFields()).toMatchObject({
+      id: entity1WithVc2.getID(),
+      name: 'blah',
+      dateField: date,
+    });
+    expect(genericLocalMemoryCacherLoadManySpy).toBeCalledWith([
+      cacheKeyMaker('id', entity1WithVc2.getID()),
+    ]);
+    expect(genericLocalMemoryCacherLoadManySpy).toBeCalledTimes(2);
+  });
+
+  it('respects the parameters of a noop cache', async () => {
+    const viewerContext = new TestViewerContext(
+      createNoopLocalMemoryIntegrationTestEntityCompanionProvider()
+    );
+    const cacheAdapter = viewerContext.entityCompanionProvider.getCompanionForEntity(
+      LocalMemoryTestEntity,
+      LocalMemoryTestEntity.getCompanionDefinition()
+    )['tableDataCoordinator']['cacheAdapter'];
+    const cacheKeyMaker = cacheAdapter['makeCacheKey'].bind(cacheAdapter);
+
+    const date = new Date();
+    const entity1Created = await LocalMemoryTestEntity.creator(viewerContext)
+      .setField('name', 'blah')
+      .setField('dateField', date)
+      .enforceCreateAsync();
+
+    // loading an entity will try to put it in cache but it's a noop cache, so it should be a miss
+    const entity1 = await LocalMemoryTestEntity.loader(viewerContext)
+      .enforcing()
+      .loadByIDAsync(entity1Created.getID());
+
+    const entitySpecificGenericCacher =
+      LocalMemoryCacheAdapterProvider.localMemoryCacheAdapterMap.get(
+        LocalMemoryTestEntity.getCompanionDefinition().entityConfiguration.tableName
+      )!['genericLocalMemoryCacher'];
+    const cachedResult = await entitySpecificGenericCacher.loadManyAsync([
+      cacheKeyMaker('id', entity1.getID()),
+    ]);
+    const cachedValue = cachedResult.get(cacheKeyMaker('id', entity1.getID()))!;
+    expect(cachedValue).toMatchObject({
+      status: CacheStatus.MISS,
+    });
+
+    // a non existent db fetch should try to write negative result ('') but it's a noop cache, so it should be a miss
+    const nonExistentId = uuidv4();
+
+    const entityNonExistentResult = await LocalMemoryTestEntity.loader(viewerContext).loadByIDAsync(
+      nonExistentId
+    );
+    expect(entityNonExistentResult.ok).toBe(false);
+
+    const nonExistentCachedResult = await entitySpecificGenericCacher.loadManyAsync([
+      cacheKeyMaker('id', nonExistentId),
+    ]);
+    expect(nonExistentCachedResult.get(cacheKeyMaker('id', nonExistentId))).toMatchObject({
+      status: CacheStatus.MISS,
+    });
+  });
+});

packages/entity-cache-adapter-local-memory/src/__tests__/LocalMemoryCacheAdapter-test.ts

@@ -0,0 +1,125 @@
+import { CacheStatus, UUIDField, EntityConfiguration } from '@expo/entity';
+
+import GenericLocalMemoryCacher, {
+  DOES_NOT_EXIST_LOCAL_MEMORY_CACHE,
+} from '../GenericLocalMemoryCacher';
+import LocalMemoryCacheAdapter from '../LocalMemoryCacheAdapter';
+
+type BlahFields = {
+  id: string;
+};
+
+const entityConfiguration = new EntityConfiguration<BlahFields>({
+  idField: 'id',
+  tableName: 'blah',
+  schema: {
+    id: new UUIDField({ columnName: 'id', cache: true }),
+  },
+  databaseAdapterFlavor: 'postgres',
+  cacheAdapterFlavor: 'local-memory',
+});
+
+describe(LocalMemoryCacheAdapter, () => {
+  describe('loadManyAsync', () => {
+    it('returns appropriate cache results', async () => {
+      const cacheAdapter = new LocalMemoryCacheAdapter(
+        entityConfiguration,
+        GenericLocalMemoryCacher.createLRUCache({
+          maxSize: Number.MAX_SAFE_INTEGER,
+          ttlSeconds: Number.MAX_SAFE_INTEGER,
+        })
+      );
+
+      const cacheHits = new Map<string, Readonly<BlahFields>>([['test-id-1', { id: 'test-id-1' }]]);
+      await cacheAdapter.cacheManyAsync('id', cacheHits);
+      await cacheAdapter.cacheDBMissesAsync('id', ['test-id-2']);
+
+      const results = await cacheAdapter.loadManyAsync('id', [
+        'test-id-1',
+        'test-id-2',
+        'test-id-3',
+      ]);
+
+      expect(results.get('test-id-1')).toMatchObject({
+        status: CacheStatus.HIT,
+        item: { id: 'test-id-1' },
+      });
+      expect(results.get('test-id-2')).toMatchObject({ status: CacheStatus.NEGATIVE });
+      expect(results.get('test-id-3')).toMatchObject({ status: CacheStatus.MISS });
+      expect(results.size).toBe(3);
+    });
+
+    it('returns empty map when passed empty array of fieldValues', async () => {
+      const cacheAdapter = new LocalMemoryCacheAdapter(
+        entityConfiguration,
+        GenericLocalMemoryCacher.createLRUCache({
+          maxSize: Number.MAX_SAFE_INTEGER,
+          ttlSeconds: Number.MAX_SAFE_INTEGER,
+        })
+      );
+      const results = await cacheAdapter.loadManyAsync('id', []);
+      expect(results).toEqual(new Map());
+    });
+  });
+
+  describe('cacheManyAsync', () => {
+    it('correctly caches all objects', async () => {
+      const localMemoryCache = GenericLocalMemoryCacher.createLRUCache<BlahFields>({
+        maxSize: Number.MAX_SAFE_INTEGER,
+        ttlSeconds: Number.MAX_SAFE_INTEGER,
+      });
+
+      const cacheAdapter = new LocalMemoryCacheAdapter(entityConfiguration, localMemoryCache);
+      await cacheAdapter.cacheManyAsync('id', new Map([['test-id-1', { id: 'test-id-1' }]]));
+
+      const cacheKey = cacheAdapter['makeCacheKey']('id', 'test-id-1');
+      expect(localMemoryCache.get(cacheKey)).toMatchObject({
+        id: 'test-id-1',
+      });
+    });
+  });
+
+  describe('cacheDBMissesAsync', () => {
+    it('correctly caches misses', async () => {
+      const localMemoryCache = GenericLocalMemoryCacher.createLRUCache<BlahFields>({
+        maxSize: Number.MAX_SAFE_INTEGER,
+        ttlSeconds: Number.MAX_SAFE_INTEGER,
+      });
+
+      const cacheAdapter = new LocalMemoryCacheAdapter(entityConfiguration, localMemoryCache);
+      await cacheAdapter.cacheDBMissesAsync('id', ['test-id-1']);
+
+      const cacheKey = cacheAdapter['makeCacheKey']('id', 'test-id-1');
+      expect(localMemoryCache.get(cacheKey)).toEqual(DOES_NOT_EXIST_LOCAL_MEMORY_CACHE);
+    });
+  });
+
+  describe('invalidateManyAsync', () => {
+    it('invalidates correctly', async () => {
+      const localMemoryCache = GenericLocalMemoryCacher.createLRUCache<BlahFields>({
+        maxSize: Number.MAX_SAFE_INTEGER,
+        ttlSeconds: Number.MAX_SAFE_INTEGER,
+      });
+
+      const cacheAdapter = new LocalMemoryCacheAdapter(entityConfiguration, localMemoryCache);
+      await cacheAdapter.cacheManyAsync('id', new Map([['test-id-1', { id: 'test-id-1' }]]));
+      await cacheAdapter.cacheDBMissesAsync('id', ['test-id-2']);
+      await cacheAdapter.invalidateManyAsync('id', ['test-id-1', 'test-id-2']);
+
+      const results = await cacheAdapter.loadManyAsync('id', ['test-id-1', 'test-id-2']);
+      expect(results.get('test-id-1')).toMatchObject({ status: CacheStatus.MISS });
+      expect(results.get('test-id-2')).toMatchObject({ status: CacheStatus.MISS });
+    });
+
+    it('returns when passed empty array of fieldValues', async () => {
+      const cacheAdapter = new LocalMemoryCacheAdapter(
+        entityConfiguration,
+        GenericLocalMemoryCacher.createLRUCache<BlahFields>({
+          maxSize: Number.MAX_SAFE_INTEGER,
+          ttlSeconds: Number.MAX_SAFE_INTEGER,
+        })
+      );
+      await cacheAdapter.invalidateManyAsync('id', []);
+    });
+  });
+});

packages/entity-cache-adapter-local-memory/src/index.ts

@@ -0,0 +1,10 @@
+/* eslint-disable tsdoc/syntax */
+/**
+ * @packageDocumentation
+ * @module @expo/entity-cache-adapter-local-memory
+ */
+
+export { default as LocalMemoryCacheAdapter } from './LocalMemoryCacheAdapter';
+export { default as LocalMemoryCacheAdapterProvider } from './LocalMemoryCacheAdapterProvider';
+export { default as GenericLocalMemoryCacher } from './GenericLocalMemoryCacher';
+export * from './GenericLocalMemoryCacher';

packages/entity-cache-adapter-local-memory/src/testfixtures/LocalMemoryTestEntity.ts

@@ -0,0 +1,100 @@
+import {
+  AlwaysAllowPrivacyPolicyRule,
+  EntityPrivacyPolicy,
+  ViewerContext,
+  UUIDField,
+  DateField,
+  StringField,
+  EntityConfiguration,
+  EntityCompanionDefinition,
+  Entity,
+} from '@expo/entity';
+
+export type LocalMemoryTestEntityFields = {
+  id: string;
+  name: string;
+  dateField: Date | null;
+};
+
+export default class LocalMemoryTestEntity extends Entity<
+  LocalMemoryTestEntityFields,
+  string,
+  ViewerContext
+> {
+  static getCompanionDefinition(): EntityCompanionDefinition<
+    LocalMemoryTestEntityFields,
+    string,
+    ViewerContext,
+    LocalMemoryTestEntity,
+    LocalMemoryTestEntityPrivacyPolicy
+  > {
+    return localMemoryTestEntityCompanionDefinition;
+  }
+}
+
+export class LocalMemoryTestEntityPrivacyPolicy extends EntityPrivacyPolicy<
+  LocalMemoryTestEntityFields,
+  string,
+  ViewerContext,
+  LocalMemoryTestEntity
+> {
+  protected override readonly createRules = [
+    new AlwaysAllowPrivacyPolicyRule<
+      LocalMemoryTestEntityFields,
+      string,
+      ViewerContext,
+      LocalMemoryTestEntity
+    >(),
+  ];
+  protected override readonly readRules = [
+    new AlwaysAllowPrivacyPolicyRule<
+      LocalMemoryTestEntityFields,
+      string,
+      ViewerContext,
+      LocalMemoryTestEntity
+    >(),
+  ];
+  protected override readonly updateRules = [
+    new AlwaysAllowPrivacyPolicyRule<
+      LocalMemoryTestEntityFields,
+      string,
+      ViewerContext,
+      LocalMemoryTestEntity
+    >(),
+  ];
+  protected override readonly deleteRules = [
+    new AlwaysAllowPrivacyPolicyRule<
+      LocalMemoryTestEntityFields,
+      string,
+      ViewerContext,
+      LocalMemoryTestEntity
+    >(),
+  ];
+}
+
+export const localMemoryTestEntityConfiguration =
+  new EntityConfiguration<LocalMemoryTestEntityFields>({
+    idField: 'id',
+    tableName: 'local_memory_test_entities',
+    schema: {
+      id: new UUIDField({
+        columnName: 'id',
+        cache: true,
+      }),
+      name: new StringField({
+        columnName: 'name',
+        cache: true,
+      }),
+      dateField: new DateField({
+        columnName: 'date_field',
+      }),
+    },
+    databaseAdapterFlavor: 'postgres',
+    cacheAdapterFlavor: 'local-memory',
+  });
+
+const localMemoryTestEntityCompanionDefinition = new EntityCompanionDefinition({
+  entityClass: LocalMemoryTestEntity,
+  entityConfiguration: localMemoryTestEntityConfiguration,
+  privacyPolicyClass: LocalMemoryTestEntityPrivacyPolicy,
+});

packages/entity-cache-adapter-local-memory/src/testfixtures/createLocalMemoryIntegrationTestEntityCompanionProvider.ts

@@ -0,0 +1,48 @@
+import {
+  NoOpEntityMetricsAdapter,
+  IEntityMetricsAdapter,
+  EntityCompanionProvider,
+  StubQueryContextProvider,
+  StubDatabaseAdapterProvider,
+} from '@expo/entity';
+
+import { LocalMemoryCacheAdapterProvider } from '../LocalMemoryCacheAdapterProvider';
+
+export const createLocalMemoryIntegrationTestEntityCompanionProvider = (
+  localMemoryOptions: { maxSize?: number; ttlSeconds?: number } = {},
+  metricsAdapter: IEntityMetricsAdapter = new NoOpEntityMetricsAdapter()
+): EntityCompanionProvider => {
+  const localMemoryCacheAdapterProvider =
+    localMemoryOptions.maxSize === 0 && localMemoryOptions.ttlSeconds === 0
+      ? LocalMemoryCacheAdapterProvider.getNoOpProvider()
+      : LocalMemoryCacheAdapterProvider.getProvider(localMemoryOptions);
+  return new EntityCompanionProvider(
+    metricsAdapter,
+    new Map([
+      [
+        'postgres',
+        {
+          adapterProvider: new StubDatabaseAdapterProvider(),
+          queryContextProvider: StubQueryContextProvider,
+        },
+      ],
+    ]),
+    new Map([
+      [
+        'local-memory',
+        {
+          cacheAdapterProvider: localMemoryCacheAdapterProvider,
+        },
+      ],
+    ])
+  );
+};
+
+export const createNoopLocalMemoryIntegrationTestEntityCompanionProvider = (
+  metricsAdapter: IEntityMetricsAdapter = new NoOpEntityMetricsAdapter()
+): EntityCompanionProvider => {
+  return createLocalMemoryIntegrationTestEntityCompanionProvider(
+    { maxSize: 0, ttlSeconds: 0 },
+    metricsAdapter
+  );
+};

packages/entity-cache-adapter-local-memory/tsconfig.json

@@ -0,0 +1,7 @@
+{
+  "extends": "../../tsconfig.json",
+  "compilerOptions": {
+    "outDir": "build",
+  },
+  "include": ["src"]
+}

packages/entity-cache-adapter-redis/CHANGELOG.md

@@ -3,6 +3,25 @@
 All notable changes to this project will be documented in this file.
 See [Conventional Commits](https://conventionalcommits.org) for commit guidelines.
 
+# [0.24.0](https://github.com/expo/entity/compare/v0.23.0...v0.24.0) (2022-02-16)
+
+### Chores
+
+* Refactor cachers to use an abstract class and interface  ([#157](https://github.com/expo/entity/pull/157)) 
+
+
+
+
+
+# [0.23.0](https://github.com/expo/entity/compare/v0.22.0...v0.23.0) (2022-02-09)
+
+### Chores
+
+* Move data transforming responsibilities to the CacheAdapter instead of the ReadThroughEntityCache. ([#153](https://github.com/expo/entity/pull/153))
+
+
+
+
 # [0.22.0](https://github.com/expo/entity/compare/v0.21.0...v0.22.0) (2022-02-04)
 
 **Note:** Version bump only for package @expo/entity-cache-adapter-redis

packages/entity-cache-adapter-redis/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@expo/entity-cache-adapter-redis",
-  "version": "0.22.0",
+  "version": "0.24.0",
   "description": "Redis cache adapter for @expo/entity",
   "files": [
     "build",
@@ -33,6 +33,6 @@
     "ioredis": "^4.27.3"
   },
   "devDependencies": {
-    "@expo/entity": "^0.22.0"
+    "@expo/entity": "^0.24.0"
   }
 }

packages/entity-cache-adapter-redis/src/GenericRedisCacher.ts

@@ -1,6 +1,14 @@
-import { CacheLoadResult, CacheStatus } from '@expo/entity';
+import {
+  CacheLoadResult,
+  CacheStatus,
+  EntityConfiguration,
+  transformCacheObjectToFields,
+  transformFieldsToCacheObject,
+  IEntityGenericCacher,
+} from '@expo/entity';
 import { Redis } from 'ioredis';
 
+import { redisTransformerMap } from './RedisCommon';
 import wrapNativeRedisCallAsync from './errors/wrapNativeRedisCallAsync';
 
 // Sentinel value we store in Redis to negatively cache a database miss.
@@ -26,12 +34,15 @@ export interface GenericRedisCacheContext {
   ttlSecondsNegative: number;
 }
 
-export default class GenericRedisCacher {
+export default class GenericRedisCacher<TFields> implements IEntityGenericCacher<TFields> {
-  constructor(private readonly context: GenericRedisCacheContext) {}
+  constructor(
+    private readonly context: GenericRedisCacheContext,
+    private readonly entityConfiguration: EntityConfiguration<TFields>
+  ) {}
 
   public async loadManyAsync(
     keys: readonly string[]
-  ): Promise<ReadonlyMap<string, CacheLoadResult>> {
+  ): Promise<ReadonlyMap<string, CacheLoadResult<TFields>>> {
     if (keys.length === 0) {
       return new Map();
     }
@@ -40,7 +51,7 @@ export default class GenericRedisCacher {
       this.context.redisClient.mget(...keys)
     );
 
-    const results = new Map<string, CacheLoadResult>();
+    const results = new Map<string, CacheLoadResult<TFields>>();
     for (let i = 0; i < keys.length; i++) {
       const key = keys[i]!;
       const redisResult = redisResults[i];
@@ -52,7 +63,11 @@ export default class GenericRedisCacher {
       } else if (redisResult) {
         results.set(key, {
           status: CacheStatus.HIT,
-          item: JSON.parse(redisResult),
+          item: transformCacheObjectToFields(
+            this.entityConfiguration,
+            redisTransformerMap,
+            JSON.parse(redisResult)
+          ),
         });
       } else {
         results.set(key, {
@@ -63,7 +78,7 @@ export default class GenericRedisCacher {
     return results;
   }
 
-  public async cacheManyAsync(objectMap: ReadonlyMap<string, object>): Promise<void> {
+  public async cacheManyAsync(objectMap: ReadonlyMap<string, Readonly<TFields>>): Promise<void> {
     if (objectMap.size === 0) {
       return;
     }
@@ -72,7 +87,9 @@ export default class GenericRedisCacher {
     objectMap.forEach((object, key) => {
       redisTransaction = redisTransaction.set(
         key,
-        JSON.stringify(object),
+        JSON.stringify(
+          transformFieldsToCacheObject(this.entityConfiguration, redisTransformerMap, object)
+        ),
         'EX',
         this.context.ttlSecondsPositive
       );
@@ -80,7 +97,7 @@ export default class GenericRedisCacher {
     await wrapNativeRedisCallAsync(() => redisTransaction.exec());
   }
 
-  public async cacheDBMissesAsync(keys: string[]): Promise<void> {
+  public async cacheDBMissesAsync(keys: readonly string[]): Promise<void> {
     if (keys.length === 0) {
       return;
     }
@@ -97,7 +114,7 @@ export default class GenericRedisCacher {
     await wrapNativeRedisCallAsync(() => redisTransaction.exec());
   }
 
-  public async invalidateManyAsync(keys: string[]): Promise<void> {
+  public async invalidateManyAsync(keys: readonly string[]): Promise<void> {
     if (keys.length === 0) {
       return;
     }

packages/entity-cache-adapter-redis/src/RedisCacheAdapter.ts

@@ -1,15 +1,8 @@
-import {
+import { EntityCacheAdapter, EntityConfiguration, CacheLoadResult, mapKeys } from '@expo/entity';
-  EntityCacheAdapter,
-  EntityConfiguration,
-  CacheLoadResult,
-  FieldTransformerMap,
-  mapKeys,
-} from '@expo/entity';
 import invariant from 'invariant';
 import { Redis } from 'ioredis';
 
 import GenericRedisCacher from './GenericRedisCacher';
-import { redisTransformerMap } from './RedisCommon';
 
 export interface RedisCacheAdapterContext {
   /**
@@ -49,28 +42,27 @@ export interface RedisCacheAdapterContext {
 }
 
 export default class RedisCacheAdapter<TFields> extends EntityCacheAdapter<TFields> {
-  private readonly genericRedisCacher: GenericRedisCacher;
+  private readonly genericRedisCacher: GenericRedisCacher<TFields>;
   constructor(
     entityConfiguration: EntityConfiguration<TFields>,
     private readonly context: RedisCacheAdapterContext
   ) {
     super(entityConfiguration);
 
-    this.genericRedisCacher = new GenericRedisCacher({
+    this.genericRedisCacher = new GenericRedisCacher(
-      redisClient: context.redisClient,
+      {
-      ttlSecondsNegative: context.ttlSecondsNegative,
+        redisClient: context.redisClient,
-      ttlSecondsPositive: context.ttlSecondsPositive,
+        ttlSecondsNegative: context.ttlSecondsNegative,
-    });
+        ttlSecondsPositive: context.ttlSecondsPositive,
-  }
+      },
-
+      entityConfiguration
-  public getFieldTransformerMap(): FieldTransformerMap {
+    );
-    return redisTransformerMap;
   }
 
   public async loadManyAsync<N extends keyof TFields>(
     fieldName: N,
     fieldValues: readonly NonNullable<TFields[N]>[]
-  ): Promise<ReadonlyMap<NonNullable<TFields[N]>, CacheLoadResult>> {
+  ): Promise<ReadonlyMap<NonNullable<TFields[N]>, CacheLoadResult<TFields>>> {
     const redisCacheKeyToFieldValueMapping = new Map(
       fieldValues.map((fieldValue) => [this.makeCacheKey(fieldName, fieldValue), fieldValue])
     );
@@ -91,7 +83,7 @@ export default class RedisCacheAdapter<TFields> extends EntityCacheAdapter<TFiel
 
   public async cacheManyAsync<N extends keyof TFields>(
     fieldName: N,
-    objectMap: ReadonlyMap<NonNullable<TFields[N]>, object>
+    objectMap: ReadonlyMap<NonNullable<TFields[N]>, Readonly<TFields>>
   ): Promise<void> {
     await this.genericRedisCacher.cacheManyAsync(
       mapKeys(objectMap, (fieldValue) => this.makeCacheKey(fieldName, fieldValue))

packages/entity-cache-adapter-redis/src/__integration-tests__/GenericRedisCacher-integration-test.ts

@@ -0,0 +1,125 @@
+import { CacheStatus, ViewerContext } from '@expo/entity';
+import Redis from 'ioredis';
+import { URL } from 'url';
+
+import GenericRedisCacher from '../GenericRedisCacher';
+import { RedisCacheAdapterContext } from '../RedisCacheAdapter';
+import RedisTestEntity, {
+  redisTestEntityConfiguration,
+  RedisTestEntityFields,
+} from '../testfixtures/RedisTestEntity';
+import { createRedisIntegrationTestEntityCompanionProvider } from '../testfixtures/createRedisIntegrationTestEntityCompanionProvider';
+
+class TestViewerContext extends ViewerContext {}
+
+describe(GenericRedisCacher, () => {
+  let redisCacheAdapterContext: RedisCacheAdapterContext;
+
+  beforeAll(() => {
+    redisCacheAdapterContext = {
+      redisClient: new Redis(new URL(process.env['REDIS_URL']!).toString()),
+      makeKeyFn(...parts: string[]): string {
+        const delimiter = ':';
+        const escapedParts = parts.map((part) =>
+          part.replace('\\', '\\\\').replace(delimiter, `\\${delimiter}`)
+        );
+        return escapedParts.join(delimiter);
+      },
+      cacheKeyPrefix: 'test-',
+      cacheKeyVersion: 1,
+      ttlSecondsPositive: 86400, // 1 day
+      ttlSecondsNegative: 600, // 10 minutes
+    };
+  });
+
+  beforeEach(async () => {
+    await redisCacheAdapterContext.redisClient.flushdb();
+  });
+  afterAll(async () => {
+    redisCacheAdapterContext.redisClient.disconnect();
+  });
+
+  it('has correct caching and loading behavior', async () => {
+    const viewerContext = new TestViewerContext(
+      createRedisIntegrationTestEntityCompanionProvider(redisCacheAdapterContext)
+    );
+    const genericRedisCacher = new GenericRedisCacher(
+      {
+        redisClient: redisCacheAdapterContext.redisClient,
+        ttlSecondsNegative: redisCacheAdapterContext.ttlSecondsNegative,
+        ttlSecondsPositive: redisCacheAdapterContext.ttlSecondsPositive,
+      },
+      redisTestEntityConfiguration
+    );
+    const date = new Date();
+    const entity1Created = await RedisTestEntity.creator(viewerContext)
+      .setField('name', 'blah')
+      .setField('dateField', date)
+      .enforceCreateAsync();
+    const testKey = `test-id-key-${entity1Created.getID()}`;
+    const objectMap = new Map<string, Readonly<RedisTestEntityFields>>([
+      [testKey, entity1Created.getAllFields()],
+    ]);
+    await genericRedisCacher.cacheManyAsync(objectMap);
+
+    const cachedJSON = await redisCacheAdapterContext.redisClient.get(testKey);
+    const cachedValue = JSON.parse(cachedJSON!);
+    expect(cachedValue).toMatchObject({
+      id: entity1Created.getID(),
+      dateField: date.toISOString(),
+    });
+
+    const loadedObjectMap = await genericRedisCacher.loadManyAsync([testKey]);
+    const cacheLoadResult = loadedObjectMap.get(testKey)!;
+    expect(cacheLoadResult).toMatchObject({
+      status: CacheStatus.HIT,
+      item: entity1Created.getAllFields(),
+    });
+    expect(loadedObjectMap.size).toBe(1);
+  });
+  it('has correct negative caching behaviour', async () => {
+    const genericRedisCacher = new GenericRedisCacher(
+      {
+        redisClient: redisCacheAdapterContext.redisClient,
+        ttlSecondsNegative: redisCacheAdapterContext.ttlSecondsNegative,
+        ttlSecondsPositive: redisCacheAdapterContext.ttlSecondsPositive,
+      },
+      redisTestEntityConfiguration
+    );
+
+    const testKey = `test-id-key-non-existent-id`;
+    await genericRedisCacher.cacheDBMissesAsync([testKey]);
+    const loadedObjectMap = await genericRedisCacher.loadManyAsync([testKey]);
+    const cacheLoadResult = loadedObjectMap.get(testKey)!;
+    expect(cacheLoadResult.status).toBe(CacheStatus.NEGATIVE);
+  });
+  it('has correct invalidation behaviour', async () => {
+    const viewerContext = new TestViewerContext(
+      createRedisIntegrationTestEntityCompanionProvider(redisCacheAdapterContext)
+    );
+    const genericRedisCacher = new GenericRedisCacher(
+      {
+        redisClient: redisCacheAdapterContext.redisClient,
+        ttlSecondsNegative: redisCacheAdapterContext.ttlSecondsNegative,
+        ttlSecondsPositive: redisCacheAdapterContext.ttlSecondsPositive,
+      },
+      redisTestEntityConfiguration
+    );
+    const date = new Date();
+    const entity1Created = await RedisTestEntity.creator(viewerContext)
+      .setField('name', 'blah')
+      .setField('dateField', date)
+      .enforceCreateAsync();
+    const testKey = `test-id-key-${entity1Created.getID()}`;
+    const objectMap = new Map<string, Readonly<RedisTestEntityFields>>([
+      [testKey, entity1Created.getAllFields()],
+    ]);
+    await genericRedisCacher.cacheManyAsync(objectMap);
+
+    await genericRedisCacher.invalidateManyAsync([testKey]);
+
+    const loadedObjectMap = await genericRedisCacher.loadManyAsync([testKey]);
+    const cacheLoadResult = loadedObjectMap.get(testKey)!;
+    expect(cacheLoadResult.status).toBe(CacheStatus.MISS);
+  });
+});

packages/entity-database-adapter-knex/CHANGELOG.md

@@ -3,6 +3,22 @@
 All notable changes to this project will be documented in this file.
 See [Conventional Commits](https://conventionalcommits.org) for commit guidelines.
 
+# [0.24.0](https://github.com/expo/entity/compare/v0.23.0...v0.24.0) (2022-02-16)
+
+**Note:** Version bump only for package @expo/entity-database-adapter-knex
+
+
+
+
+
+# [0.23.0](https://github.com/expo/entity/compare/v0.22.0...v0.23.0) (2022-02-09)
+
+**Note:** Version bump only for package @expo/entity-database-adapter-knex
+
+
+
+
+
 # [0.22.0](https://github.com/expo/entity/compare/v0.21.0...v0.22.0) (2022-02-04)
 
 

packages/entity-database-adapter-knex/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@expo/entity-database-adapter-knex",
-  "version": "0.22.0",
+  "version": "0.24.0",
   "description": "Knex database adapter for @expo/entity",
   "files": [
     "build",
@@ -33,7 +33,7 @@
     "knex": "^1.0.2"
   },
   "devDependencies": {
-    "@expo/entity": "^0.22.0",
+    "@expo/entity": "^0.24.0",
     "pg": "^8.7.1"
   }
 }

packages/entity-example/CHANGELOG.md

@@ -3,6 +3,22 @@
 All notable changes to this project will be documented in this file.
 See [Conventional Commits](https://conventionalcommits.org) for commit guidelines.
 
+# [0.24.0](https://github.com/expo/entity/compare/v0.23.0...v0.24.0) (2022-02-16)
+
+**Note:** Version bump only for package @expo/entity-example
+
+
+
+
+
+# [0.23.0](https://github.com/expo/entity/compare/v0.22.0...v0.23.0) (2022-02-09)
+
+**Note:** Version bump only for package @expo/entity-example
+
+
+
+
+
 # [0.22.0](https://github.com/expo/entity/compare/v0.21.0...v0.22.0) (2022-02-04)
 
 **Note:** Version bump only for package @expo/entity-example

packages/entity-example/package.json

@@ -1,7 +1,7 @@
 {
   "name": "@expo/entity-example",
   "private": true,
-  "version": "0.22.0",
+  "version": "0.24.0",
   "description": "An example integration of the @expo/entity framework",
   "scripts": {
     "tsc": "tsc",
@@ -23,7 +23,7 @@
   "author": "Expo",
   "license": "MIT",
   "dependencies": {
-    "@expo/entity": "^0.22.0",
+    "@expo/entity": "^0.24.0",
     "apollo-server-koa": "^2.16.1",
     "graphql": "^15.3.0",
     "koa": "^2.13.0",

packages/entity-full-integration-tests/CHANGELOG.md

@@ -3,6 +3,22 @@
 All notable changes to this project will be documented in this file.
 See [Conventional Commits](https://conventionalcommits.org) for commit guidelines.
 
+# [0.24.0](https://github.com/expo/entity/compare/v0.23.0...v0.24.0) (2022-02-16)
+
+**Note:** Version bump only for package @expo/entity-full-integration-tests
+
+
+
+
+
+# [0.23.0](https://github.com/expo/entity/compare/v0.22.0...v0.23.0) (2022-02-09)
+
+**Note:** Version bump only for package @expo/entity-full-integration-tests
+
+
+
+
+
 # [0.22.0](https://github.com/expo/entity/compare/v0.21.0...v0.22.0) (2022-02-04)
 
 **Note:** Version bump only for package @expo/entity-full-integration-tests

packages/entity-full-integration-tests/package.json

@@ -1,7 +1,7 @@
 {
   "name": "@expo/entity-full-integration-tests",
   "private": true,
-  "version": "0.22.0",
+  "version": "0.24.0",
   "description": "Full redis and knex integration tests for the entity framework",
   "scripts": {
     "tsc": "tsc",
@@ -27,8 +27,8 @@
     "@expo/entity-database-adapter-knex": "*"
   },
   "devDependencies": {
-    "@expo/entity": "^0.22.0",
+    "@expo/entity": "^0.24.0",
-    "@expo/entity-cache-adapter-redis": "^0.22.0",
+    "@expo/entity-cache-adapter-redis": "^0.24.0",
-    "@expo/entity-database-adapter-knex": "^0.22.0"
+    "@expo/entity-database-adapter-knex": "^0.24.0"
   }
 }

packages/entity-ip-address-field/CHANGELOG.md

@@ -3,6 +3,22 @@
 All notable changes to this project will be documented in this file.
 See [Conventional Commits](https://conventionalcommits.org) for commit guidelines.
 
+# [0.24.0](https://github.com/expo/entity/compare/v0.23.0...v0.24.0) (2022-02-16)
+
+**Note:** Version bump only for package @expo/entity-ip-address-field
+
+
+
+
+
+# [0.23.0](https://github.com/expo/entity/compare/v0.22.0...v0.23.0) (2022-02-09)
+
+**Note:** Version bump only for package @expo/entity-ip-address-field
+
+
+
+
+
 # [0.22.0](https://github.com/expo/entity/compare/v0.21.0...v0.22.0) (2022-02-04)
 
 **Note:** Version bump only for package @expo/entity-ip-address-field

packages/entity-ip-address-field/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@expo/entity-ip-address-field",
-  "version": "0.22.0",
+  "version": "0.24.0",
   "description": "IP address EntityField definitions for @expo/entity",
   "files": [
     "build",
@@ -28,7 +28,7 @@
     "ip-address": "^8.1.0"
   },
   "devDependencies": {
-    "@expo/entity": "^0.22.0",
+    "@expo/entity": "^0.24.0",
     "@types/jsbn": "^1.2.29"
   },
   "peerDependencies": {

packages/entity-secondary-cache-redis/CHANGELOG.md

@@ -3,6 +3,24 @@
 All notable changes to this project will be documented in this file.
 See [Conventional Commits](https://conventionalcommits.org) for commit guidelines.
 
+# [0.24.0](https://github.com/expo/entity/compare/v0.23.0...v0.24.0) (2022-02-16)
+
+### Chores
+
+* Refactor cachers to use an abstract class and interface  ([#157](https://github.com/expo/entity/pull/157))
+
+
+
+
+# [0.23.0](https://github.com/expo/entity/compare/v0.22.0...v0.23.0) (2022-02-09)
+
+### Chores
+
+* Move data transforming responsibilities to the CacheAdapter instead of the RedisSecondaryEntityCache. ([#153](https://github.com/expo/entity/pull/153))
+
+
+
+
 # [0.22.0](https://github.com/expo/entity/compare/v0.21.0...v0.22.0) (2022-02-04)
 
 **Note:** Version bump only for package @expo/entity-secondary-cache-redis

packages/entity-secondary-cache-redis/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@expo/entity-secondary-cache-redis",
-  "version": "0.22.0",
+  "version": "0.24.0",
   "description": "Redis secondary cache for @expo/entity",
   "files": [
     "build",
@@ -34,8 +34,8 @@
     "ioredis": "^4.17.3"
   },
   "devDependencies": {
-    "@expo/entity": "^0.22.0",
+    "@expo/entity": "^0.24.0",
-    "@expo/entity-cache-adapter-redis": "^0.22.0",
+    "@expo/entity-cache-adapter-redis": "^0.24.0",
     "nullthrows": "^1.1.1"
   }
 }

packages/entity-secondary-cache-redis/src/RedisSecondaryEntityCache.ts

@@ -1,136 +1,20 @@
-import {
+import { EntityConfiguration, GenericSecondaryEntityCache } from '@expo/entity';
-  CacheStatus,
+import { GenericRedisCacheContext, GenericRedisCacher } from '@expo/entity-cache-adapter-redis';
-  EntityConfiguration,
-  filterMap,
-  ISecondaryEntityCache,
-  transformCacheObjectToFields,
-  transformFieldsToCacheObject,
-  zipToMap,
-} from '@expo/entity';
-import {
-  GenericRedisCacheContext,
-  GenericRedisCacher,
-  redisTransformerMap,
-} from '@expo/entity-cache-adapter-redis';
-import invariant from 'invariant';
 
 /**
  * A custom secondary read-through entity cache is a way to add a custom second layer of caching for a particular
  * single entity load. One common way this may be used is to add a second layer of caching in a hot path that makes
  * a call to {@link EntityLoader.loadManyByFieldEqualityConjunctionAsync} is guaranteed to return at most one entity.
  */
-export default class RedisSecondaryEntityCache<TFields, TLoadParams>
+export default class RedisSecondaryEntityCache<
-  implements ISecondaryEntityCache<TFields, TLoadParams>
+  TFields,
-{
+  TLoadParams
-  private readonly genericRedisCacher: GenericRedisCacher;
+> extends GenericSecondaryEntityCache<TFields, TLoadParams> {
-
   constructor(
-    private readonly entityConfiguration: EntityConfiguration<TFields>,
+    entityConfiguration: EntityConfiguration<TFields>,
     genericRedisCacheContext: GenericRedisCacheContext,
-    private readonly constructRedisKey: (params: Readonly<TLoadParams>) => string
+    constructRedisKey: (params: Readonly<TLoadParams>) => string
   ) {
-    this.genericRedisCacher = new GenericRedisCacher(genericRedisCacheContext);
+    super(new GenericRedisCacher(genericRedisCacheContext, entityConfiguration), constructRedisKey);
-  }
-
-  /**
-   * Read-through cache function. Steps:
-   *
-   * 1. Check for cached objects
-   * 2. Query the fetcher for loadParams not in the cache
-   * 3. Cache the results from the fetcher
-   * 4. Negatively cache anything missing from the fetcher
-   * 5. Return the full set of data for the query.
-   *
-   * @param loadParamsArray - array of loadParams to load from the cache
-   * @param fetcher - closure used to provide underlying data source objects for loadParams
-   * @returns map from loadParams to the entity field object
-   */
-  public async loadManyThroughAsync(
-    loadParamsArray: readonly Readonly<TLoadParams>[],
-    fetcher: (
-      fetcherLoadParamsArray: readonly Readonly<TLoadParams>[]
-    ) => Promise<ReadonlyMap<Readonly<TLoadParams>, Readonly<TFields> | null>>
-  ): Promise<ReadonlyMap<Readonly<TLoadParams>, Readonly<TFields> | null>> {
-    const redisKeys = loadParamsArray.map(this.constructRedisKey);
-    const redisKeyToLoadParamsMap = zipToMap(redisKeys, loadParamsArray);
-
-    const cacheLoadResults = await this.genericRedisCacher.loadManyAsync(redisKeys);
-
-    invariant(
-      cacheLoadResults.size === loadParamsArray.length,
-      `${this.constructor.name} loadMany should return a result for each key`
-    );
-
-    const redisKeysToFetch = Array.from(
-      filterMap(
-        cacheLoadResults,
-        (cacheLoadResult) => cacheLoadResult.status === CacheStatus.MISS
-      ).keys()
-    );
-
-    // put transformed cache hits in result map
-    const results: Map<Readonly<TLoadParams>, Readonly<TFields> | null> = new Map();
-    cacheLoadResults.forEach((cacheLoadResult, redisKey) => {
-      if (cacheLoadResult.status === CacheStatus.HIT) {
-        const loadParams = redisKeyToLoadParamsMap.get(redisKey);
-        invariant(loadParams !== undefined, 'load params should be in redis key map');
-        results.set(
-          loadParams,
-          transformCacheObjectToFields(
-            this.entityConfiguration,
-            redisTransformerMap,
-            cacheLoadResult.item
-          )
-        );
-      }
-    });
-
-    // fetch any misses from DB, add DB objects to results, cache DB results, inform cache of any missing DB results
-    if (redisKeysToFetch.length > 0) {
-      const loadParamsToFetch = redisKeysToFetch.map((redisKey) => {
-        const loadParams = redisKeyToLoadParamsMap.get(redisKey);
-        invariant(loadParams !== undefined, 'load params should be in redis key map');
-        return loadParams;
-      });
-      const fetchResults = await fetcher(loadParamsToFetch);
-
-      const fetchMisses = loadParamsToFetch.filter((loadParams) => {
-        // all values of fetchResults should be field objects or undefined
-        return !fetchResults.get(loadParams);
-      });
-
-      for (const fetchMiss of fetchMisses) {
-        results.set(fetchMiss, null);
-      }
-
-      const objectsToCache: Map<string, object> = new Map();
-      for (const [loadParams, object] of fetchResults.entries()) {
-        if (object) {
-          objectsToCache.set(
-            this.constructRedisKey(loadParams),
-            transformFieldsToCacheObject(this.entityConfiguration, redisTransformerMap, object)
-          );
-          results.set(loadParams, object);
-        }
-      }
-
-      await Promise.all([
-        this.genericRedisCacher.cacheManyAsync(objectsToCache),
-        this.genericRedisCacher.cacheDBMissesAsync(fetchMisses.map(this.constructRedisKey)),
-      ]);
-    }
-
-    return results;
-  }
-
-  /**
-   * Invalidate the cache for objects cached by constructRedisKey(loadParams).
-   *
-   * @param loadParamsArray - load params to invalidate
-   */
-  public async invalidateManyAsync(
-    loadParamsArray: readonly Readonly<TLoadParams>[]
-  ): Promise<void> {
-    await this.genericRedisCacher.invalidateManyAsync(loadParamsArray.map(this.constructRedisKey));
   }
 }

packages/entity/CHANGELOG.md

@@ -3,6 +3,27 @@
 All notable changes to this project will be documented in this file.
 See [Conventional Commits](https://conventionalcommits.org) for commit guidelines.
 
+# [0.24.0](https://github.com/expo/entity/compare/v0.23.0...v0.24.0) (2022-02-16)
+
+**Note:** Version bump only for package @expo/entity
+
+
+
+
+
+### Chores
+
+* Refactor cachers to use an abstract class and interface  ([#157](https://github.com/expo/entity/pull/157)) 
+
+# [0.23.0](https://github.com/expo/entity/compare/v0.22.0...v0.23.0) (2022-02-09)
+
+### Breaking changes
+
+* Move data transforming responsibilities to the CacheAdapter instead of the ReadThroughEntityCache. Affects any classes extending the EntityCacheAdapter and relying on the transformation behavior of the ReadThroughEntityCache. ([#153](https://github.com/expo/entity/pull/153))
+
+
+
+
 # [0.22.0](https://github.com/expo/entity/compare/v0.21.0...v0.22.0) (2022-02-04)
 
 **Note:** Version bump only for package @expo/entity

packages/entity/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@expo/entity",
-  "version": "0.22.0",
+  "version": "0.24.0",
   "description": "A privacy-first data model",
   "files": [
     "build",

packages/entity/src/EntityCacheAdapter.ts

@@ -1,5 +1,4 @@
 import EntityConfiguration from './EntityConfiguration';
-import { FieldTransformerMap } from './internal/EntityFieldTransformationUtils';
 import { CacheLoadResult } from './internal/ReadThroughEntityCache';
 
 /**
@@ -9,13 +8,6 @@ import { CacheLoadResult } from './internal/ReadThroughEntityCache';
 export default abstract class EntityCacheAdapter<TFields> {
   constructor(protected readonly entityConfiguration: EntityConfiguration<TFields>) {}
 
-  /**
-   * Transformer definitions for field types. Used to modify values as they are read from or written to
-   * the cache. Override in concrete subclasses to change transformation behavior.
-   * If a field type is not present in the map, then fields of that type will not be transformed.
-   */
-  public abstract getFieldTransformerMap(): FieldTransformerMap;
-
   /**
    * Load many objects from cache.
    * @param fieldName - object field being queried
@@ -25,7 +17,7 @@ export default abstract class EntityCacheAdapter<TFields> {
   public abstract loadManyAsync<N extends keyof TFields>(
     fieldName: N,
     fieldValues: readonly NonNullable<TFields[N]>[]
-  ): Promise<ReadonlyMap<NonNullable<TFields[N]>, CacheLoadResult>>;
+  ): Promise<ReadonlyMap<NonNullable<TFields[N]>, CacheLoadResult<TFields>>>;
 
   /**
    * Cache many objects fetched from the DB.
@@ -34,7 +26,7 @@ export default abstract class EntityCacheAdapter<TFields> {
    */
   public abstract cacheManyAsync<N extends keyof TFields>(
     fieldName: N,
-    objectMap: ReadonlyMap<NonNullable<TFields[N]>, object>
+    objectMap: ReadonlyMap<NonNullable<TFields[N]>, Readonly<TFields>>
   ): Promise<void>;
 
   /**

packages/entity/src/EntityFieldDefinition.ts

@@ -28,6 +28,9 @@ export enum EntityEdgeDeletionBehavior {
   SET_NULL,
 }
 
+/**
+ * Defines an association between entities. An association is primarily used to define cascading deletion behavior.
+ */
 export interface EntityAssociationDefinition<
   TViewerContext extends ViewerContext,
   TAssociatedFields,
@@ -83,6 +86,10 @@ export interface EntityAssociationDefinition<
   edgeDeletionBehavior?: EntityEdgeDeletionBehavior;
 }
 
+/**
+ * Definition for a field referencing a column in the underlying database. Specifies things like
+ * cache behavior and associations, and handles input validation.
+ */
 export abstract class EntityFieldDefinition<T> {
   readonly columnName: string;
   readonly cache: boolean;
@@ -93,6 +100,7 @@ export abstract class EntityFieldDefinition<T> {
    * @param cache - Whether or not to cache loaded instances of the entity by this field. The column name is
    *              used to derive a cache key for the cache entry. If true, this column must be able uniquely
    *              identify the entity.
+   * @param association - Defines the association behavior for an entity that this column references.
    */
   constructor({
     columnName,

packages/entity/src/EntityFields.ts

@@ -2,59 +2,104 @@ import { validate as validateUUID } from 'uuid';
 
 import { EntityFieldDefinition } from './EntityFieldDefinition';
 
+/**
+ * {@link EntityFieldDefinition} for a column with a JS string type.
+ */
 export class StringField extends EntityFieldDefinition<string> {
   protected validateInputValueInternal(value: string): boolean {
     return typeof value === 'string';
   }
 }
+
+/**
+ * {@link EntityFieldDefinition} for a column with a JS string type.
+ * Enforces that the string is a valid UUID.
+ */
 export class UUIDField extends StringField {
   protected override validateInputValueInternal(value: string): boolean {
     return validateUUID(value);
   }
 }
+
+/**
+ * {@link EntityFieldDefinition} for a column with a JS Date type.
+ */
 export class DateField extends EntityFieldDefinition<Date> {
   protected validateInputValueInternal(value: Date): boolean {
     return value instanceof Date;
   }
 }
+
+/**
+ * {@link EntityFieldDefinition} for a column with a JS boolean type.
+ */
 export class BooleanField extends EntityFieldDefinition<boolean> {
   protected validateInputValueInternal(value: boolean): boolean {
     return typeof value === 'boolean';
   }
 }
 
+/**
+ * {@link EntityFieldDefinition} for a column with a JS number type.
+ * Enforces that the number is an integer.
+ */
 export class IntField extends EntityFieldDefinition<number> {
   protected validateInputValueInternal(value: number): boolean {
     return typeof value === 'number' && Number.isInteger(value);
   }
 }
 
+/**
+ * {@link EntityFieldDefinition} for a column with a JS number type.
+ * Enforces that the number is a float (which includes integers in JS).
+ */
 export class FloatField extends EntityFieldDefinition<number> {
   protected validateInputValueInternal(value: number): boolean {
     return typeof value === 'number';
   }
 }
 
+/**
+ * {@link EntityFieldDefinition} for a column with a JS string array type.
+ * Enforces that every member of the string array is a string.
+ */
 export class StringArrayField extends EntityFieldDefinition<string[]> {
   protected validateInputValueInternal(value: string[]): boolean {
     return Array.isArray(value) && value.every((subValue) => typeof subValue === 'string');
   }
 }
+
+/**
+ * {@link EntityFieldDefinition} for a column with a JS JSON object type.
+ */
 export class JSONObjectField extends EntityFieldDefinition<object> {
   protected validateInputValueInternal(value: object): boolean {
     return typeof value === 'object' && !Array.isArray(value);
   }
 }
+
+/**
+ * {@link EntityFieldDefinition} for a enum column with a JS string or number type.
+ */
 export class EnumField extends EntityFieldDefinition<string | number> {
   protected validateInputValueInternal(value: string | number): boolean {
     return typeof value === 'number' || typeof value === 'string';
   }
 }
+
+/**
+ * {@link EntityFieldDefinition} for a column with a JS JSON array type.
+ */
 export class JSONArrayField extends EntityFieldDefinition<any[]> {
   protected validateInputValueInternal(value: any[]): boolean {
     return Array.isArray(value);
   }
 }
+
+/**
+ * {@link EntityFieldDefinition} for a column that may be a JS JSON array type.
+ * Does not do any validation.
+ */
 export class MaybeJSONArrayField extends EntityFieldDefinition<any | any[]> {
   protected validateInputValueInternal(_value: any): boolean {
     return true;

packages/entity/src/GenericSecondaryEntityCache.ts

@@ -0,0 +1,98 @@
+import invariant from 'invariant';
+
+import { ISecondaryEntityCache } from './EntitySecondaryCacheLoader';
+import IEntityGenericCacher from './IEntityGenericCacher';
+import { CacheStatus } from './internal/ReadThroughEntityCache';
+import { filterMap, zipToMap } from './utils/collections/maps';
+
+/**
+ * A custom secondary read-through entity cache is a way to add a custom second layer of caching for a particular
+ * single entity load. One common way this may be used is to add a second layer of caching in a hot path that makes
+ * a call to {@link EntityLoader.loadManyByFieldEqualityConjunctionAsync} is guaranteed to return at most one entity.
+ */
+export default abstract class GenericSecondaryEntityCache<TFields, TLoadParams>
+  implements ISecondaryEntityCache<TFields, TLoadParams>
+{
+  constructor(
+    protected readonly cacher: IEntityGenericCacher<TFields>,
+    protected readonly constructCacheKey: (params: Readonly<TLoadParams>) => string
+  ) {}
+
+  public async loadManyThroughAsync(
+    loadParamsArray: readonly Readonly<TLoadParams>[],
+    fetcher: (
+      fetcherLoadParamsArray: readonly Readonly<TLoadParams>[]
+    ) => Promise<ReadonlyMap<Readonly<TLoadParams>, Readonly<TFields> | null>>
+  ): Promise<ReadonlyMap<Readonly<TLoadParams>, Readonly<TFields> | null>> {
+    const cacheKeys = loadParamsArray.map(this.constructCacheKey);
+    const cacheKeyToLoadParamsMap = zipToMap(cacheKeys, loadParamsArray);
+
+    const cacheLoadResults = await this.cacher.loadManyAsync(cacheKeys);
+
+    invariant(
+      cacheLoadResults.size === loadParamsArray.length,
+      `${this.constructor.name} loadMany should return a result for each key`
+    );
+
+    const cacheKeysToFetch = Array.from(
+      filterMap(
+        cacheLoadResults,
+        (cacheLoadResult) => cacheLoadResult.status === CacheStatus.MISS
+      ).keys()
+    );
+
+    // put cache hits in result map
+    const results: Map<Readonly<TLoadParams>, Readonly<TFields> | null> = new Map();
+    cacheLoadResults.forEach((cacheLoadResult, cacheKey) => {
+      if (cacheLoadResult.status === CacheStatus.HIT) {
+        const loadParams = cacheKeyToLoadParamsMap.get(cacheKey);
+        invariant(loadParams !== undefined, 'load params should be in cache key map');
+        results.set(loadParams, cacheLoadResult.item);
+      }
+    });
+
+    // fetch any misses from DB, add DB objects to results, cache DB results, inform cache of any missing DB results
+    if (cacheKeysToFetch.length > 0) {
+      const loadParamsToFetch = cacheKeysToFetch.map((cacheKey) => {
+        const loadParams = cacheKeyToLoadParamsMap.get(cacheKey);
+        invariant(loadParams !== undefined, 'load params should be in cache key map');
+        return loadParams;
+      });
+      const fetchResults = await fetcher(loadParamsToFetch);
+
+      const fetchMisses = loadParamsToFetch.filter((loadParams) => {
+        // all values of fetchResults should be field objects or undefined
+        return !fetchResults.get(loadParams);
+      });
+
+      for (const fetchMiss of fetchMisses) {
+        results.set(fetchMiss, null);
+      }
+
+      const objectsToCache: Map<string, Readonly<TFields>> = new Map();
+      for (const [loadParams, object] of fetchResults.entries()) {
+        if (object) {
+          objectsToCache.set(this.constructCacheKey(loadParams), object);
+          results.set(loadParams, object);
+        }
+      }
+
+      await Promise.all([
+        this.cacher.cacheManyAsync(objectsToCache),
+        this.cacher.cacheDBMissesAsync(fetchMisses.map(this.constructCacheKey)),
+      ]);
+    }
+
+    return results;
+  }
+
+  /**
+   * Invalidate the cache for objects cached by constructCacheKey(loadParams).
+   *
+   * @param loadParamsArray - load params to invalidate
+   */
+  public invalidateManyAsync(loadParamsArray: readonly Readonly<TLoadParams>[]): Promise<void> {
+    const cacheKeys = loadParamsArray.map(this.constructCacheKey);
+    return this.cacher.invalidateManyAsync(cacheKeys);
+  }
+}

packages/entity/src/IEntityGenericCacher.ts

@@ -0,0 +1,15 @@
+import { CacheLoadResult } from './internal/ReadThroughEntityCache';
+
+/**
+ * A cacher stores and loads key-value pairs. It also supports negative caching - it stores the absence
+ * of keys that don't exist in the backing datastore.
+ */
+export default interface IEntityGenericCacher<TFields> {
+  loadManyAsync(keys: readonly string[]): Promise<ReadonlyMap<string, CacheLoadResult<TFields>>>;
+
+  cacheManyAsync(objectMap: ReadonlyMap<string, Readonly<TFields>>): Promise<void>;
+
+  cacheDBMissesAsync(keys: readonly string[]): Promise<void>;
+
+  invalidateManyAsync(keys: readonly string[]): Promise<void>;
+}

packages/entity/src/index.ts

@@ -4,6 +4,7 @@
  * @module @expo/entity
  */
 
+export { default as GenericSecondaryEntityCache } from './GenericSecondaryEntityCache';
 export { default as EnforcingEntityLoader } from './EnforcingEntityLoader';
 export { default as Entity } from './Entity';
 export * from './Entity';
@@ -43,6 +44,7 @@ export * from './EntityQueryContext';
 export { default as IEntityCacheAdapterProvider } from './IEntityCacheAdapterProvider';
 export { default as IEntityDatabaseAdapterProvider } from './IEntityDatabaseAdapterProvider';
 export { default as EntityQueryContextProvider } from './EntityQueryContextProvider';
+export { default as IEntityGenericCacher } from './IEntityGenericCacher';
 export { default as ReadonlyEntity } from './ReadonlyEntity';
 export { default as ViewerContext } from './ViewerContext';
 export { default as ViewerScopedEntityCompanion } from './ViewerScopedEntityCompanion';

packages/entity/src/internal/ReadThroughEntityCache.ts

@@ -3,11 +3,6 @@ import invariant from 'invariant';
 import EntityCacheAdapter from '../EntityCacheAdapter';
 import EntityConfiguration from '../EntityConfiguration';
 import { filterMap } from '../utils/collections/maps';
-import {
-  FieldTransformerMap,
-  transformCacheObjectToFields,
-  transformFieldsToCacheObject,
-} from './EntityFieldTransformationUtils';
 
 export enum CacheStatus {
   HIT,
@@ -15,10 +10,10 @@ export enum CacheStatus {
   NEGATIVE,
 }
 
-export type CacheLoadResult =
+export type CacheLoadResult<TFields> =
   | {
       status: CacheStatus.HIT;
-      item: Readonly<object>;
+      item: Readonly<TFields>;
     }
   | {
       status: CacheStatus.MISS;
@@ -32,14 +27,10 @@ export type CacheLoadResult =
  * {@link EntityCacheAdapter} within the {@link EntityDataManager}.
  */
 export default class ReadThroughEntityCache<TFields> {
-  private readonly fieldTransformerMap: FieldTransformerMap;
-
   constructor(
     private readonly entityConfiguration: EntityConfiguration<TFields>,
     private readonly entityCacheAdapter: EntityCacheAdapter<TFields>
-  ) {
+  ) {}
-    this.fieldTransformerMap = entityCacheAdapter.getFieldTransformerMap();
-  }
 
   private isFieldCacheable<N extends keyof TFields>(fieldName: N): boolean {
     return this.entityConfiguration.cacheableKeys.has(fieldName);
@@ -91,13 +82,7 @@ export default class ReadThroughEntityCache<TFields> {
     const results: Map<NonNullable<TFields[N]>, readonly Readonly<TFields>[]> = new Map();
     cacheLoadResults.forEach((cacheLoadResult, fieldValue) => {
       if (cacheLoadResult.status === CacheStatus.HIT) {
-        results.set(fieldValue, [
+        results.set(fieldValue, [cacheLoadResult.item]);
-          transformCacheObjectToFields(
-            this.entityConfiguration,
-            this.fieldTransformerMap,
-            cacheLoadResult.item
-          ),
-        ]);
       }
     });
 
@@ -110,7 +95,7 @@ export default class ReadThroughEntityCache<TFields> {
         return !objectsFromFulfillerForFv || objectsFromFulfillerForFv.length === 0;
       });
 
-      const objectsToCache: Map<NonNullable<TFields[N]>, object> = new Map();
+      const objectsToCache: Map<NonNullable<TFields[N]>, Readonly<TFields>> = new Map();
       for (const [fieldValue, objects] of dbFetchResults.entries()) {
         if (objects.length > 1) {
           // multiple objects received for what was supposed to be a unique query, don't add to return map nor cache
@@ -123,14 +108,7 @@ export default class ReadThroughEntityCache<TFields> {
         }
         const uniqueObject = objects[0];
         if (uniqueObject) {
-          objectsToCache.set(
+          objectsToCache.set(fieldValue, uniqueObject);
-            fieldValue,
-            transformFieldsToCacheObject(
-              this.entityConfiguration,
-              this.fieldTransformerMap,
-              uniqueObject
-            )
-          );
           results.set(fieldValue, [uniqueObject]);
         }
       }

packages/entity/src/internal/__tests__/ReadThroughEntityCache-test.ts

@@ -40,7 +40,6 @@ describe(ReadThroughEntityCache, () => {
   describe('readManyThroughAsync', () => {
     it('fetches from DB upon cache miss and caches the result', async () => {
       const cacheAdapterMock = mock<EntityCacheAdapter<BlahFields>>();
-      when(cacheAdapterMock.getFieldTransformerMap()).thenReturn(new Map());
       const cacheAdapter = instance(cacheAdapterMock);
       const entityCache = new ReadThroughEntityCache(makeEntityConfiguration(true), cacheAdapter);
       const fetcher = createIdFetcher(['wat', 'who']);
@@ -77,7 +76,6 @@ describe(ReadThroughEntityCache, () => {
 
     it('does not fetch from the DB or cache results when all cache fetches are hits', async () => {
       const cacheAdapterMock = mock<EntityCacheAdapter<BlahFields>>();
-      when(cacheAdapterMock.getFieldTransformerMap()).thenReturn(new Map());
       const cacheAdapter = instance(cacheAdapterMock);
       const entityCache = new ReadThroughEntityCache(makeEntityConfiguration(true), cacheAdapter);
       const fetcher = createIdFetcher(['wat', 'who']);
@@ -114,7 +112,6 @@ describe(ReadThroughEntityCache, () => {
 
     it('negatively caches db misses', async () => {
       const cacheAdapterMock = mock<EntityCacheAdapter<BlahFields>>();
-      when(cacheAdapterMock.getFieldTransformerMap()).thenReturn(new Map());
       const cacheAdapter = instance(cacheAdapterMock);
       const entityCache = new ReadThroughEntityCache(makeEntityConfiguration(true), cacheAdapter);
 
@@ -135,7 +132,6 @@ describe(ReadThroughEntityCache, () => {
 
     it('does not return or fetch negatively cached results from DB', async () => {
       const cacheAdapterMock = mock<EntityCacheAdapter<BlahFields>>();
-      when(cacheAdapterMock.getFieldTransformerMap()).thenReturn(new Map());
       const cacheAdapter = instance(cacheAdapterMock);
       const entityCache = new ReadThroughEntityCache(makeEntityConfiguration(true), cacheAdapter);
       const fetcher = createIdFetcher([]);
@@ -153,7 +149,6 @@ describe(ReadThroughEntityCache, () => {
 
     it('does a mix and match of hit, miss, and negative', async () => {
       const cacheAdapterMock = mock<EntityCacheAdapter<BlahFields>>();
-      when(cacheAdapterMock.getFieldTransformerMap()).thenReturn(new Map());
       const cacheAdapter = instance(cacheAdapterMock);
       const entityCache = new ReadThroughEntityCache(makeEntityConfiguration(true), cacheAdapter);
       const fetcher = createIdFetcher(['wat', 'who', 'why']);
@@ -189,7 +184,6 @@ describe(ReadThroughEntityCache, () => {
 
     it('does not call into cache for field that is not cacheable', async () => {
       const cacheAdapterMock = mock<EntityCacheAdapter<BlahFields>>();
-      when(cacheAdapterMock.getFieldTransformerMap()).thenReturn(new Map());
       const cacheAdapter = instance(cacheAdapterMock);
       const entityCache = new ReadThroughEntityCache(makeEntityConfiguration(false), cacheAdapter);
       const fetcher = createIdFetcher(['wat']);
@@ -197,44 +191,6 @@ describe(ReadThroughEntityCache, () => {
       verify(cacheAdapterMock.loadManyAsync('id', anything())).never();
       expect(result).toEqual(new Map([['wat', [{ id: 'wat' }]]]));
     });
-
-    it('transforms fields for cache storage', async () => {
-      const cacheAdapterMock = mock<EntityCacheAdapter<BlahFields>>();
-      when(cacheAdapterMock.getFieldTransformerMap()).thenReturn(
-        new Map([
-          [
-            UUIDField.name,
-            {
-              read: (val) => val.split('-')[0],
-              write: (val) => `${val}-in-cache`,
-            },
-          ],
-        ])
-      );
-      const cacheAdapter = instance(cacheAdapterMock);
-      const entityCache = new ReadThroughEntityCache(makeEntityConfiguration(true), cacheAdapter);
-      const fetcher = createIdFetcher(['wat', 'who']);
-
-      when(cacheAdapterMock.loadManyAsync('id', deepEqual(['wat', 'who']))).thenResolve(
-        new Map([
-          ['wat', { status: CacheStatus.MISS }],
-          ['who', { status: CacheStatus.HIT, item: { id: 'who-in-cache' } }],
-        ])
-      );
-
-      const result = await entityCache.readManyThroughAsync('id', ['wat', 'who'], fetcher);
-
-      verify(cacheAdapterMock.loadManyAsync('id', deepEqual(['wat', 'who']))).once();
-      verify(
-        cacheAdapterMock.cacheManyAsync('id', deepEqual(new Map([['wat', { id: 'wat-in-cache' }]])))
-      ).once();
-      expect(result).toEqual(
-        new Map([
-          ['wat', [{ id: 'wat' }]],
-          ['who', [{ id: 'who' }]],
-        ])
-      );
-    });
   });
 
   describe('invalidateManyAsync', () => {

packages/entity/src/utils/testing/StubCacheAdapter.ts

@@ -3,7 +3,6 @@ import invariant from 'invariant';
 import EntityCacheAdapter from '../../EntityCacheAdapter';
 import EntityConfiguration from '../../EntityConfiguration';
 import IEntityCacheAdapterProvider from '../../IEntityCacheAdapterProvider';
-import { FieldTransformerMap } from '../../internal/EntityFieldTransformationUtils';
 import { CacheStatus, CacheLoadResult } from '../../internal/ReadThroughEntityCache';
 
 export class NoCacheStubCacheAdapterProvider implements IEntityCacheAdapterProvider {
@@ -15,15 +14,11 @@ export class NoCacheStubCacheAdapterProvider implements IEntityCacheAdapterProvi
 }
 
 export class NoCacheStubCacheAdapter<TFields> extends EntityCacheAdapter<TFields> {
-  public getFieldTransformerMap(): FieldTransformerMap {
-    return new Map();
-  }
-
   public async loadManyAsync<N extends keyof TFields>(
     _fieldName: N,
     fieldValues: readonly NonNullable<TFields[N]>[]
-  ): Promise<ReadonlyMap<NonNullable<TFields[N]>, CacheLoadResult>> {
+  ): Promise<ReadonlyMap<NonNullable<TFields[N]>, CacheLoadResult<TFields>>> {
-    return fieldValues.reduce((acc: Map<NonNullable<TFields[N]>, CacheLoadResult>, v) => {
+    return fieldValues.reduce((acc: Map<NonNullable<TFields[N]>, CacheLoadResult<TFields>>, v) => {
       acc.set(v, {
         status: CacheStatus.MISS,
       });
@@ -33,7 +28,7 @@ export class NoCacheStubCacheAdapter<TFields> extends EntityCacheAdapter<TFields
 
   public async cacheManyAsync<N extends keyof TFields>(
     _fieldName: N,
-    _objectMap: ReadonlyMap<NonNullable<TFields[N]>, object>
+    _objectMap: ReadonlyMap<NonNullable<TFields[N]>, Readonly<TFields>>
   ): Promise<void> {}
 
   public async cacheDBMissesAsync<N extends keyof TFields>(
@@ -53,27 +48,26 @@ export class InMemoryFullCacheStubCacheAdapterProvider implements IEntityCacheAd
   getCacheAdapter<TFields>(
     entityConfiguration: EntityConfiguration<TFields>
   ): EntityCacheAdapter<TFields> {
-    return new InMemoryFullCacheStubCacheAdapter(entityConfiguration, this.cache);
+    return new InMemoryFullCacheStubCacheAdapter(
+      entityConfiguration,
+      this.cache as Map<string, Readonly<TFields>>
+    );
   }
 }
 
 export class InMemoryFullCacheStubCacheAdapter<TFields> extends EntityCacheAdapter<TFields> {
   constructor(
     entityConfiguration: EntityConfiguration<TFields>,
-    readonly cache: Map<string, Readonly<object>>
+    readonly cache: Map<string, Readonly<TFields>>
   ) {
     super(entityConfiguration);
   }
 
-  public getFieldTransformerMap(): FieldTransformerMap {
-    return new Map();
-  }
-
   public async loadManyAsync<N extends keyof TFields>(
     fieldName: N,
     fieldValues: readonly NonNullable<TFields[N]>[]
-  ): Promise<ReadonlyMap<NonNullable<TFields[N]>, CacheLoadResult>> {
+  ): Promise<ReadonlyMap<NonNullable<TFields[N]>, CacheLoadResult<TFields>>> {
-    const results = new Map<NonNullable<TFields[N]>, CacheLoadResult>();
+    const results = new Map<NonNullable<TFields[N]>, CacheLoadResult<TFields>>();
     fieldValues.forEach((fieldValue) => {
       const cacheKey = this.createCacheKey(fieldName, fieldValue);
       if (!this.cache.has(cacheKey)) {
@@ -94,7 +88,7 @@ export class InMemoryFullCacheStubCacheAdapter<TFields> extends EntityCacheAdapt
 
   public async cacheManyAsync<N extends keyof TFields>(
     fieldName: N,
-    objectMap: ReadonlyMap<NonNullable<TFields[N]>, object>
+    objectMap: ReadonlyMap<NonNullable<TFields[N]>, Readonly<TFields>>
   ): Promise<void> {
     objectMap.forEach((obj, fieldValue) => {
       const cacheKey = this.createCacheKey(fieldName, fieldValue);

yarn.lock

@@ -507,28 +507,33 @@
     exec-sh "^0.3.2"
     minimist "^1.2.0"
 
+"@expo/entity-cache-adapter-local-memory@file:packages/entity-cache-adapter-local-memory":
+  version "0.23.0"
+  dependencies:
+    lru-cache "^7.3.1"
+
 "@expo/entity-cache-adapter-redis@file:packages/entity-cache-adapter-redis":
-  version "0.21.0"
+  version "0.23.0"
   dependencies:
     ioredis "^4.27.3"
 
 "@expo/entity-database-adapter-knex@file:packages/entity-database-adapter-knex":
-  version "0.21.0"
+  version "0.23.0"
   dependencies:
     knex "^1.0.2"
 
 "@expo/entity-ip-address-field@file:packages/entity-ip-address-field":
-  version "0.21.0"
+  version "0.23.0"
   dependencies:
     ip-address "^8.1.0"
 
 "@expo/entity-secondary-cache-redis@file:packages/entity-secondary-cache-redis":
-  version "0.21.0"
+  version "0.23.0"
   dependencies:
     ioredis "^4.17.3"
 
 "@expo/entity@file:packages/entity":
-  version "0.21.0"
+  version "0.23.0"
   dependencies:
     "@expo/results" "^1.0.0"
     dataloader "^2.0.0"
@@ -1995,6 +2000,11 @@
   resolved "https://registry.yarnpkg.com/@types/long/-/long-4.0.1.tgz#459c65fa1867dafe6a8f322c4c51695663cc55e9"
   integrity sha512-5tXH6Bx/kNGd3MgffdmP4dy2Z+G4eaXw0SE81Tq3BNadtnMR5/ySMzX4SLEzHJzSmPNn4HIdpQsBvXMUykr58w==
 
+"@types/lru-cache@^5.1.1":
+  version "5.1.1"
+  resolved "https://registry.yarnpkg.com/@types/lru-cache/-/lru-cache-5.1.1.tgz#c48c2e27b65d2a153b19bfc1a317e30872e01eef"
+  integrity sha512-ssE3Vlrys7sdIzs5LOxCzTVMsU7i9oa/IaW92wF32JFb3CVczqOkru2xspuKczHEbG3nvmPY7IFqVmGGHdNbYw==
+
 "@types/mime@*":
   version "2.0.1"
   resolved "https://registry.yarnpkg.com/@types/mime/-/mime-2.0.1.tgz#dc488842312a7f075149312905b5e3c0b054c79d"
@@ -6565,6 +6575,11 @@ lru-cache@^6.0.0:
   dependencies:
     yallist "^4.0.0"
 
+lru-cache@^7.3.1:
+  version "7.3.1"
+  resolved "https://registry.yarnpkg.com/lru-cache/-/lru-cache-7.3.1.tgz#7702e80694ec2bf19865567a469f2b081fcf53f5"
+  integrity sha512-nX1x4qUrKqwbIAhv4s9et4FIUVzNOpeY07bsjGUy8gwJrXH/wScImSQqXErmo/b2jZY2r0mohbLA9zVj7u1cNw==
+
 lunr@^2.3.9:
   version "2.3.9"
   resolved "https://registry.yarnpkg.com/lunr/-/lunr-2.3.9.tgz#18b123142832337dd6e964df1a5a7707b25d35e1"