Add refresh method to handle invalidation (#2)

Author: Ben Clark

.vscode/settings.json

@@ -50,5 +50,8 @@
     "**/.eslintcache": true,
     "**/.cache": true,
     "**/.fuse_hidden*": true
+  },
+  "editor.codeActionsOnSave": {
+    "source.fixAll.eslint": true
   }
 }

README.md

@@ -34,7 +34,11 @@ const myObjectCache = new LeprechaunCache({
   onBackgroundError: e => { console.error(e); }
 })
 
-const myObject = myObjectCache.get('object-id') //get the object with key 'object-id'. If it doesn't exist, onMiss will be called, and the data will be stored in the cache with a soft TTL of 1000ms
+const myObject = await myObjectCache.get('object-id') //get the object with key 'object-id'. If it doesn't exist, onMiss will be called, and the data will be stored in the cache with a soft TTL of 1000ms
+
+const myObject = await myObjectCache.refresh('object-id') //Force refresh (calls the onMiss handler and updates the cache) and return the result
+
+await myObjectCache.clear('object-id') //Remove the item from the cache
 ```
 
 ## Constructor Options

package-lock.json

@@ -1,6 +1,6 @@
 {
   "name": "@acuris/leprechaun-cache",
-  "version": "0.0.6",
+  "version": "0.0.7",
   "private": false,
   "description": "Caching library that supports double checked caching and stale returns to avoid stampede and slow responses",
   "keywords": [

package.json

@@ -72,6 +72,10 @@ export class LeprechaunCache<T extends Cacheable = Cacheable> {
     return promise
   }
 
+  public async refresh(key: string): Promise<T> {
+    return this.updateCache(key, this.softTtlMs, true)
+  }
+
   private async doGet(key: string, ttl: number): Promise<T> {
     const result = await this.cacheStore.get(this.keyPrefix + key)
     if (!result) {

src/leprechaun-cache.ts

@@ -224,6 +224,7 @@ describe('Leprechaun Cache (integration)', () => {
     const results2 = await cache.get(key)
     expect(results2).to.deep.equal(data2)
   })
+
   it('should save and return undefined and null and false correctly', async () => {
     const onMissStub = sandbox.stub()
     onMissStub.withArgs('key-undefined').resolves(undefined)
@@ -263,4 +264,31 @@ describe('Leprechaun Cache (integration)', () => {
     expect(result5).to.equal(0)
     expect(await cache.get('key-zero')).to.equal(0)
   })
+
+  it('should refresh the cache when refresh is called when not yet expired', async () => {
+    const onMissStub = sandbox.stub()
+    const res1 = { res: 1 }
+    const res2 = { res: 2 }
+    onMissStub.onCall(0).resolves(res1)
+    onMissStub.onCall(1).resolves(res2)
+
+    const cache = new LeprechaunCache({
+      softTtlMs: 10000,
+      hardTtlMs: 10000,
+      waitForUnlockMs: 1000,
+      spinMs: 50,
+      lockTtlMs: 1000,
+      cacheStore,
+      returnStale: true,
+      onMiss: onMissStub
+    })
+
+    const result1 = await cache.get('key')
+    expect(result1).to.deep.equal(res1)
+    await delay(10)
+
+    await cache.refresh('key')
+    const result2 = await cache.get('key')
+    expect(result2).to.deep.equal(res2)
+  })
 })

test/integration/leprechaun-cache-redis.spec.ts

@@ -274,4 +274,30 @@ describe('Leprechaun Cache', () => {
 
     expect(await memoryCacheStore.get('prefix-key')).to.not.be.null
   })
+
+  it('should refresh the cache when refresh is called when not yet expired', async () => {
+    const onMissStub = sandbox.stub()
+    const res1 = { res: 1 }
+    const res2 = { res: 2 }
+    onMissStub.onCall(0).resolves(res1)
+    onMissStub.onCall(1).resolves(res2)
+
+    const cache = new LeprechaunCache({
+      softTtlMs: 10000,
+      hardTtlMs: 10000,
+      waitForUnlockMs: 1000,
+      spinMs: 50,
+      lockTtlMs: 1000,
+      cacheStore: memoryCacheStore,
+      returnStale: true,
+      onMiss: onMissStub
+    })
+
+    const result1 = await cache.get('key')
+    expect(result1).to.deep.equal(res1)
+
+    await cache.refresh('key')
+    const result2 = await cache.get('key')
+    expect(result2).to.deep.equal(res2)
+  })
 })