From 9bb93f3fe5ad7a9c182b8cb81014ca0d0342cb20 Mon Sep 17 00:00:00 2001
From: domingo1021 <domingo.backend@gmail.com>
Date: Sun, 30 Jun 2024 15:46:13 +0800
Subject: [PATCH] refactor: add cacheError decorator to catch cache error (#9)

---
 src/cores/decorators/cacheError.decorator.ts | 22 ++++++++++++++++++++
 src/modules/cache/cache.service.ts           |  4 ++++
 2 files changed, 26 insertions(+)
 create mode 100644 src/cores/decorators/cacheError.decorator.ts

diff --git a/src/cores/decorators/cacheError.decorator.ts b/src/cores/decorators/cacheError.decorator.ts
new file mode 100644
index 0000000..0f2c77a
--- /dev/null
+++ b/src/cores/decorators/cacheError.decorator.ts
@@ -0,0 +1,22 @@
+/**
+ * Loose the cache dependency by wrapping the cache errors, if cache malfunction, the application will still work.
+ *
+ * @returns {Promise<any>}
+ */
+export const WrapCacheErrors = () => {
+  return (_target: any, _propertyKey: string, descriptor: PropertyDescriptor) => {
+    const originalMethod = descriptor.value;
+
+    descriptor.value = async function (...args: any[]) {
+      try {
+        const result = await originalMethod.apply(this, args);
+        return result;
+      } catch (err) {
+        console.error('Cache Error: ', err.message);
+        return null;
+      }
+    };
+
+    return descriptor;
+  };
+};
diff --git a/src/modules/cache/cache.service.ts b/src/modules/cache/cache.service.ts
index 6a232fc..a4606b7 100644
--- a/src/modules/cache/cache.service.ts
+++ b/src/modules/cache/cache.service.ts
@@ -3,6 +3,8 @@ import { Injectable, Inject, OnModuleDestroy } from '@nestjs/common';
 
 import { Cache } from 'cache-manager';
 
+import { WrapCacheErrors } from '#cores/decorators/cacheError.decorator';
+
 @Injectable()
 export class CacheService implements OnModuleDestroy {
   constructor(@Inject(CACHE_MANAGER) private cacheManager: Cache) {}
@@ -13,6 +15,7 @@ export class CacheService implements OnModuleDestroy {
    * @param {string} key - The key of the value to retrieve.
    * @returns {Promise<T | null>} The cached value, or null if the value is not in the cache.
    */
+  @WrapCacheErrors()
   async get<T>(key: string): Promise<T | null> {
     const cachedValue = await this.cacheManager.get<T>(key);
     if (!cachedValue) return null;
@@ -26,6 +29,7 @@ export class CacheService implements OnModuleDestroy {
    * @param ttl the time to live in seconds, default is until 4:00 AM next day
    * @returns {Promise<void>}
    */
+  @WrapCacheErrors()
   async set(key: string, value: any, ttl: number = -1): Promise<void> {
     if (ttl === -1) {
       const now = new Date();