lib: add nowAbsolute to fast timers (#3749)

Signed-off-by: flakey5 <[email protected]>

Author: flakey5

benchmarks/timers/now-absolute.mjs

@@ -0,0 +1,13 @@
+import { bench, group, run } from 'mitata'
+import timers from '../../lib/util/timers.js'
+
+group(() => {
+  bench('Date.now()', () => {
+    Date.now()
+  })
+  bench('nowAbsolute()', () => {
+    timers.nowAbsolute()
+  })
+})
+
+await run()

lib/cache/memory-cache-store.js

@@ -1,6 +1,7 @@
 'use strict'
 
 const { Writable } = require('node:stream')
+const { nowAbsolute } = require('../util/timers.js')
 
 /**
  * @typedef {import('../../types/cache-interceptor.d.ts').default.CacheKey} CacheKey
@@ -76,7 +77,7 @@ class MemoryCacheStore {
 
     const topLevelKey = `${key.origin}:${key.path}`
 
-    const now = Date.now()
+    const now = nowAbsolute()
     const entry = this.#entries.get(topLevelKey)?.find((entry) => (
       entry.deleteAt > now &&
       entry.method === key.method &&

lib/handler/cache-handler.js

@@ -6,6 +6,7 @@ const {
   parseCacheControlHeader,
   parseVaryHeader
 } = require('../util/cache')
+const { nowAbsolute } = require('../util/timers.js')
 
 function noop () {}
 
@@ -121,7 +122,7 @@ class CacheHandler extends DecoratorHandler {
       return downstreamOnHeaders()
     }
 
-    const now = Date.now()
+    const now = nowAbsolute()
     const staleAt = determineStaleAt(now, headers, cacheControlDirectives)
     if (staleAt) {
       const varyDirectives = this.#cacheKey.headers && headers.vary
@@ -300,7 +301,7 @@ function determineStaleAt (now, headers, cacheControlDirectives) {
     // https://www.rfc-editor.org/rfc/rfc9111.html#section-5.3
     const expiresDate = new Date(headers.expire)
     if (expiresDate instanceof Date && !isNaN(expiresDate)) {
-      return now + (Date.now() - expiresDate.getTime())
+      return now + (nowAbsolute() - expiresDate.getTime())
     }
   }
 

lib/interceptor/cache.js

@@ -7,6 +7,7 @@ const CacheHandler = require('../handler/cache-handler')
 const MemoryCacheStore = require('../cache/memory-cache-store')
 const CacheRevalidationHandler = require('../handler/cache-revalidation-handler')
 const { assertCacheStore, assertCacheMethods, makeCacheKey } = require('../util/cache.js')
+const { nowAbsolute } = require('../util/timers.js')
 
 const AGE_HEADER = Buffer.from('age')
 
@@ -101,7 +102,7 @@ module.exports = (opts = {}) => {
         if (typeof handler.onHeaders === 'function') {
           // Add the age header
           // https://www.rfc-editor.org/rfc/rfc9111.html#name-age
-          const age = Math.round((Date.now() - cachedAt) / 1000)
+          const age = Math.round((nowAbsolute() - cachedAt) / 1000)
 
           // TODO (fix): What if rawHeaders already contains age header?
           rawHeaders = [...rawHeaders, AGE_HEADER, Buffer.from(`${age}`)]
@@ -133,7 +134,7 @@ module.exports = (opts = {}) => {
         }
 
         // Check if the response is stale
-        const now = Date.now()
+        const now = nowAbsolute()
         if (now < result.staleAt) {
           // Dump request body.
           if (util.isStream(opts.body)) {

lib/util/timers.js

@@ -21,6 +21,13 @@
  */
 let fastNow = 0
 
+/**
+ * The fastNowAbsolute variable contains the rough result of Date.now()
+ *
+ * @type {number}
+ */
+let fastNowAbsolute = Date.now()
+
 /**
  * RESOLUTION_MS represents the target resolution time in milliseconds.
  *
@@ -122,6 +129,8 @@ function onTick () {
    */
   fastNow += TICK_MS
 
+  fastNowAbsolute = Date.now()
+
   /**
    * The `idx` variable is used to iterate over the `fastTimers` array.
    * Expired timers are removed by replacing them with the last element in the array.
@@ -390,6 +399,9 @@ module.exports = {
   now () {
     return fastNow
   },
+  nowAbsolute () {
+    return fastNowAbsolute
+  },
   /**
    * Trigger the onTick function to process the fastTimers array.
    * Exported for testing purposes only.
@@ -419,5 +431,11 @@ module.exports = {
    * Marking as deprecated to discourage any use outside of testing.
    * @deprecated
    */
-  kFastTimer
+  kFastTimer,
+  /**
+   * Exporting for testing purposes only.
+   * Marking as deprecated to discourage any use outside of testing.
+   * @deprecated
+   */
+  RESOLUTION_MS
 }

test/cache-interceptor/cache-stores.js

@@ -5,6 +5,7 @@ const { deepStrictEqual, notEqual, equal } = require('node:assert')
 const { Readable } = require('node:stream')
 const { once } = require('node:events')
 const MemoryCacheStore = require('../../lib/cache/memory-cache-store')
+const { nowAbsolute } = require('../../lib/util/timers.js')
 
 cacheStoreTests(MemoryCacheStore)
 
@@ -32,9 +33,9 @@ function cacheStoreTests (CacheStore) {
         statusCode: 200,
         statusMessage: '',
         rawHeaders: [Buffer.from('1'), Buffer.from('2'), Buffer.from('3')],
-        cachedAt: Date.now(),
-        staleAt: Date.now() + 10000,
-        deleteAt: Date.now() + 20000
+        cachedAt: nowAbsolute(),
+        staleAt: nowAbsolute() + 10000,
+        deleteAt: nowAbsolute() + 20000
       }
       const requestBody = ['asd', '123']
 
@@ -71,9 +72,9 @@ function cacheStoreTests (CacheStore) {
         statusCode: 200,
         statusMessage: '',
         rawHeaders: [Buffer.from('1'), Buffer.from('2'), Buffer.from('3')],
-        cachedAt: Date.now(),
-        staleAt: Date.now() + 10000,
-        deleteAt: Date.now() + 20000
+        cachedAt: nowAbsolute(),
+        staleAt: nowAbsolute() + 10000,
+        deleteAt: nowAbsolute() + 20000
       }
       const anotherBody = ['asd2', '1234']
 
@@ -108,9 +109,9 @@ function cacheStoreTests (CacheStore) {
         statusCode: 200,
         statusMessage: '',
         rawHeaders: [Buffer.from('1'), Buffer.from('2'), Buffer.from('3')],
-        cachedAt: Date.now() - 10000,
-        staleAt: Date.now() - 1,
-        deleteAt: Date.now() + 20000
+        cachedAt: nowAbsolute() - 10000,
+        staleAt: nowAbsolute() - 1,
+        deleteAt: nowAbsolute() + 20000
       }
       const requestBody = ['part1', 'part2']
 
@@ -140,9 +141,9 @@ function cacheStoreTests (CacheStore) {
       const requestValue = {
         statusCode: 200,
         statusMessage: '',
-        cachedAt: Date.now() - 20000,
-        staleAt: Date.now() - 10000,
-        deleteAt: Date.now() - 5
+        cachedAt: nowAbsolute() - 20000,
+        staleAt: nowAbsolute() - 10000,
+        deleteAt: nowAbsolute() - 5
       }
       const requestBody = ['part1', 'part2']
 
@@ -174,9 +175,9 @@ function cacheStoreTests (CacheStore) {
         vary: {
           'some-header': 'hello world'
         },
-        cachedAt: Date.now(),
-        staleAt: Date.now() + 10000,
-        deleteAt: Date.now() + 20000
+        cachedAt: nowAbsolute(),
+        staleAt: nowAbsolute() + 10000,
+        deleteAt: nowAbsolute() + 20000
       }
       const requestBody = ['part1', 'part2']
 

test/interceptors/cache.js

@@ -6,6 +6,7 @@ const { createServer } = require('node:http')
 const { once } = require('node:events')
 const FakeTimers = require('@sinonjs/fake-timers')
 const { Client, interceptors, cacheStores } = require('../../index')
+const { tick } = require('../../lib/util/timers')
 
 describe('Cache Interceptor', () => {
   test('doesn\'t cache request w/ no cache-control header', async () => {
@@ -160,6 +161,7 @@ describe('Cache Interceptor', () => {
     const clock = FakeTimers.install({
       shouldClearNativeTimers: true
     })
+    tick(0)
 
     const server = createServer((req, res) => {
       res.setHeader('cache-control', 'public, s-maxage=1, stale-while-revalidate=10')
@@ -205,6 +207,7 @@ describe('Cache Interceptor', () => {
     strictEqual(await response.body.text(), 'asd')
 
     clock.tick(1500)
+    tick(1500)
 
     // Now we send two more requests. Both of these should reach the origin,
     //  but now with a conditional header asking if the resource has been

test/timers.js

@@ -255,4 +255,16 @@ describe('timers', () => {
 
     await t.completed
   })
+
+  test('nowAbsolute', (t) => {
+    t = tspl(t, { plan: 1 })
+
+    const actualNow = Date.now()
+
+    const lowerBound = actualNow - timers.RESOLUTION_MS
+    const upperBound = actualNow + timers.RESOLUTION_MS
+    const fastNowAbsolute = timers.nowAbsolute()
+
+    t.equal(fastNowAbsolute >= lowerBound && fastNowAbsolute <= upperBound, true)
+  })
 })