Merge pull request #21 from oslabs-beta/refactored/cache_expiration

Refactored cache expiration
oslabs-beta · Sep 28, 2023 · e0453ea · e0453ea
2 parents 1e71127 + 0113ea1
commit e0453ea
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Showing 8 changed files with 96 additions and 50 deletions.
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -1,5 +1,11 @@
 # @grpcexpress/grpcexpress
 
+## 0.2.1
+
+### Patch Changes
+
+- Refactored the cache expiration from setTimeout to checking an expiration date
+
 ## 0.2.0
 
 ### Minor Changes

diff --git a/package.json b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@grpcexpress/grpcexpress",
-  "version": "0.2.0",
+  "version": "0.2.1",
   "description": "",
   "private": false,
   "main": "./dist/index.js",

diff --git a/src/CacheStore.test.ts b/src/CacheStore.test.ts
@@ -5,7 +5,7 @@ import { CacheStore } from './CacheStore';
 describe('CacheStore', () => {
   let cacheStore: CacheStore;
   beforeAll(() => {
-    cacheStore = new CacheStore();
+    cacheStore = new CacheStore(600000);
   });
 
   it('should create a cache store', () => {
@@ -16,7 +16,7 @@ describe('CacheStore', () => {
     const buffer = new Uint8Array([1]);
     cacheStore.subscribe('testKey', buffer);
     const value = cacheStore.get('testKey');
-    expect(value).toEqual({ buffer: buffer });
+    expect(value).toEqual(buffer);
   });
 
   it('should be able to unsubscribe', () => {

diff --git a/src/CacheStore.ts b/src/CacheStore.ts
@@ -1,31 +1,47 @@
 export class CacheStore {
   #cache: {
-    data: Map<string, { buffer: Uint8Array }>;
-    capacity: number; // ~5MB
+    data: Map<
+      string,
+      {
+        buffer: Uint8Array;
+        expirationDate: Date;
+      }
+    >;
+    cacheDuration: number;
   };
 
-  constructor() {
-    this.#cache = this.initStore();
+  constructor(cacheDuration: number) {
+    this.#cache = this.initStore(cacheDuration);
     this.loadStore = this.loadStore.bind(this);
     this.loadStore();
     this.syncStore = this.syncStore.bind(this);
     window.addEventListener('beforeunload', this.syncStore);
   }
 
-  initStore(capacity: number = 2) {
+  initStore(cacheDuration: number) {
     const cache = new Map();
     return {
       data: cache,
-      capacity: capacity,
+      cacheDuration,
     };
   }
 
-  subscribe(key: string, buffer: Uint8Array) {
+  subscribe(
+    key: string,
+    buffer: Uint8Array,
+    cacheDuration: number = this.#cache.cacheDuration
+  ) {
     if (this.#cache.data.has(key)) {
       this.#cache.data.delete(key);
     }
 
-    this.#cache.data.set(key, { buffer });
+    const expiration = new Date();
+    expiration.setTime(expiration.getTime() + cacheDuration);
+
+    this.#cache.data.set(key, {
+      buffer,
+      expirationDate: expiration,
+    });
   }
 
   unsubscribe(key: string) {
@@ -34,14 +50,21 @@ export class CacheStore {
 
   get(key: string) {
     const value = this.#cache.data.get(key);
-    return value;
+    // if the key doesn't exist return
+    if (!value) return;
+    // if the cache has expired, delete it and return
+    if (new Date() > value.expirationDate) {
+      this.unsubscribe(key);
+      return;
+    }
+    return value.buffer;
   }
 
   syncStore() {
-    const arr: [string, string][] = [];
+    const arr: [string, string, string][] = [];
     // iterate through the map, push the key and buffer to an array
     this.#cache.data.forEach((v, k) => {
-      arr.push([k, v.buffer.toString()]);
+      arr.push([k, v.buffer.toString(), v.expirationDate.toISOString()]);
     });
 
     // stringify the array so it can be saved to local storage
@@ -53,15 +76,16 @@ export class CacheStore {
 
     if (!data) return;
 
-    const json = JSON.parse(data) as [string, string][];
+    const json = JSON.parse(data) as [string, string, string][];
 
     json.forEach(array => {
       const buffer = new Uint8Array(array[1].split(',').map(e => Number(e)));
-      this.subscribe(array[0], buffer);
+      const difference = Number(new Date(array[2])) - Number(new Date());
+      if (difference > 0) {
+        this.subscribe(array[0], buffer, difference);
+      }
     });
   }
 }
 
-const cacheStore = new CacheStore();
-
-export default cacheStore;
+export default CacheStore;
diff --git a/src/PendingStore.test.ts b/src/PendingStore.test.ts
@@ -1,8 +1,11 @@
 import { describe, expect, it } from 'vitest';
 
-import pendingStore from './PendingStore';
+import CacheStore from './CacheStore';
+import PendingStore from './PendingStore';
 
 describe('PendingStore', () => {
+  const cacheStore = new CacheStore(600000);
+  const pendingStore = new PendingStore(cacheStore);
   it('should be able to set a function call as pending', () => {
     pendingStore.setPending('test');
     expect(pendingStore.has('test')).toEqual(true);

diff --git a/src/PendingStore.ts b/src/PendingStore.ts
@@ -1,4 +1,4 @@
-import cacheStore from './CacheStore';
+import CacheStore from './CacheStore';
 
 type item = {
   isPending: boolean;
@@ -7,9 +7,11 @@ type item = {
 
 class PendingStore {
   #store: { [key: string]: item };
+  #cacheStore: CacheStore;
 
-  constructor() {
+  constructor(cacheStore: CacheStore) {
     this.#store = {};
+    this.#cacheStore = cacheStore;
   }
 
   setPending(key: string) {
@@ -21,7 +23,7 @@ class PendingStore {
 
   setDone(key: string) {
     for (const resolve of this.#store[key].callbacks) {
-      resolve(cacheStore.get(key));
+      resolve(this.#cacheStore.get(key));
     }
     delete this.#store[key];
   }
@@ -39,6 +41,4 @@ class PendingStore {
   }
 }
 
-const pendingStore = new PendingStore();
-
-export default pendingStore;
+export default PendingStore;
diff --git a/src/grpcExpressClient.test.ts b/src/grpcExpressClient.test.ts
@@ -1,15 +1,14 @@
 import { beforeAll, describe, expect, it } from 'vitest';
-import { StocksServiceClient } from '../../example/frontend_react/protos/StocksServiceClientPb';
-import { User } from '../../example/frontend_react/protos/stocks_pb';
-import cacheStore from './CacheStore';
+import { StocksServiceClient } from '../example/frontend_react/protos/StocksServiceClientPb';
+import { User } from '../example/frontend_react/protos/stocks_pb';
 import grpcExpressClient from './grpcExpressClient';
 
 describe('grpcExpressClient', () => {
   let Client;
   let user: User;
 
   beforeAll(() => {
-    Client = grpcExpressClient(StocksServiceClient);
+    Client = grpcExpressClient(StocksServiceClient, 30000);
     user = new User();
   });
 
@@ -21,7 +20,12 @@ describe('grpcExpressClient', () => {
   it('should be able to get stock list with existing user', async () => {
     const client = new Client('http://localhost:8080');
     user.setUsername('Murat');
-    const stocks = await client.getStocks(user, {});
+    const stocks = await client.getStocks(user, {
+      cacheOptions: {
+        cache: 'cache',
+        duration: 10000,
+      },
+    });
     expect(stocks.toObject().stocksList.length).greaterThan(0);
   });
 
@@ -32,15 +36,6 @@ describe('grpcExpressClient', () => {
     expect(stocks.toObject().stocksList.length).toEqual(0);
   });
 
-  it('should be able to cache a response', async () => {
-    const client = new Client('http://localhost:8080');
-    user.setUsername('Murat');
-    const stocks = await client.getStocks(user, {});
-    const key = `getStocks:${user.serializeBinary()}`;
-    const cachedBuffer = cacheStore.get(key)?.buffer;
-    expect(cachedBuffer).toEqual(stocks.serializeBinary());
-  });
-
   it('should be able to return a cached response', async () => {
     const client = new Client('http://localhost:8080');
     user.setUsername('Arthur');
@@ -55,7 +50,9 @@ describe('grpcExpressClient', () => {
     const client = new Client('http://localhost:8080');
     user.setUsername('Shiyu');
     await client.getStocks(user, {
-      cacheOption: 'nocache',
+      cacheOptions: {
+        cache: 'nocache',
+      },
     });
     const start = new Date();
     await client.getStocks(user, {});

diff --git a/src/grpcExpressClient.ts b/src/grpcExpressClient.ts
@@ -1,11 +1,15 @@
 import { RpcError } from 'grpc-web';
-import cacheStore from './CacheStore';
+import CacheStore from './CacheStore';
 import deserializerStore from './DeserializerStore';
-import pendingStore from './PendingStore';
+import PendingStore from './PendingStore';
 
 export function grpcExpressClient<T extends { new (...args: any[]): object }>(
-  constructor: T
+  constructor: T,
+  cacheDuration: number = 600000 // defaults to 10 minutes
 ) {
+  const cacheStore = new CacheStore(cacheDuration);
+  const pendingStore = new PendingStore(cacheStore);
+
   return class extends constructor {
     constructor(...args: any[]) {
       super(...args);
@@ -18,11 +22,16 @@ export function grpcExpressClient<T extends { new (...args: any[]): object }>(
       for (const method of methods) {
         const geMethod = async (
           request: any,
-          metadata?: { [key: string]: string },
+          metadata?: { [key: string]: string } & {
+            cacheOptions?: {
+              cache: string;
+              duration: number;
+            };
+          },
           callback?: (err: RpcError, response: any) => void
         ): Promise<any> => {
-          const { cacheOption } = metadata || {};
-          delete metadata?.cacheOption;
+          const { cacheOptions } = metadata || {};
+          delete metadata?.cacheOptions;
 
           // we do not cache response when called using the callback method
           if (callback) {
@@ -34,7 +43,8 @@ export function grpcExpressClient<T extends { new (...args: any[]): object }>(
             );
           }
 
-          switch (cacheOption) {
+          // if no cache is passed, skip the caching step
+          switch (cacheOptions?.cache) {
             case 'nocache':
               return await constructor.prototype[method].call(
                 this,
@@ -54,7 +64,7 @@ export function grpcExpressClient<T extends { new (...args: any[]): object }>(
             if (deserializerStore.has(method)) {
               const deserialize = deserializerStore.getDeserializer(method);
 
-              return deserialize(cache.buffer);
+              return deserialize(cache);
             }
           }
 
@@ -76,7 +86,13 @@ export function grpcExpressClient<T extends { new (...args: any[]): object }>(
             );
 
             const serialized = response.serializeBinary();
-            cacheStore.subscribe(key, serialized);
+            cacheStore.subscribe(
+              key,
+              serialized,
+              // if a duration is passed in the function call
+              // override the default duration
+              cacheOptions?.duration || cacheDuration
+            );
 
             const deserializer =
               response.__proto__.constructor.deserializeBinary;