feat(cache): added the built-in nodejs/sqlite as the in-memory cache.

lib/interceptor/cache.js

@@ -1,19 +1,21 @@
 import assert from 'node:assert'
-// import { LRUCache } from 'lru-cache'
 import { DecoratorHandler, parseHeaders, parseCacheControl } from '../utils.js'
+import { DatabaseSync } from 'node:sqlite' // --experimental-sqlite
 
 class CacheHandler extends DecoratorHandler {
   #handler
   #store
   #key
+  #opts
   #value = null
 
-  constructor({ key, handler, store }) {
+  constructor({ key, handler, store, opts = [] }) {
     super(handler)
 
     this.#key = key
     this.#handler = handler
     this.#store = store
+    this.#opts = opts
   }
 
   onConnect(abort) {
@@ -64,11 +66,10 @@ class CacheHandler extends DecoratorHandler {
             (rawHeaders?.reduce((xs, x) => xs + x.length, 0) ?? 0) +
             (statusMessage?.length ?? 0) +
             64,
-          ttl: ttl * 1e3,
+          ttl, // in ms!
         }
       }
     }
-
     return this.#handler.onHeaders(statusCode, rawHeaders, resume, statusMessage, headers)
   }
 
@@ -88,20 +89,16 @@ class CacheHandler extends DecoratorHandler {
 
   onComplete(rawTrailers) {
     if (this.#value) {
-      // get
-      const entries = this.#handler.entries
       const resHeaders = parseHeaders(this.#value.data.rawHeaders)
-      const reqHeaders = this.#handler.opts
+      const reqHeaders = this.#opts
 
-      // set
       this.#value.data.rawTrailers = rawTrailers
       this.#value.size = this.#value.size
         ? this.#value.size + rawTrailers?.reduce((xs, x) => xs + x.length, 0)
         : 0
       this.#value.vary = formatVaryData(resHeaders, reqHeaders)
-      entries.push(this.#value)
-      sortEntriesByVary(entries)
-      this.#store.set(this.#key, entries)
+
+      this.#store.set(this.#key, this.#value)
     }
     return this.#handler.onComplete(rawTrailers)
   }
@@ -115,20 +112,72 @@ function formatVaryData(resHeaders, reqHeaders) {
     .filter(([_key, val]) => val)
 }
 
-// TODO (fix): Async filesystem cache.
+// Can we move this class somewhere else, to the util.js file or its own module?
 class CacheStore {
-  constructor({ maxSize = 1024 * 1024, maxEntrySize = 128 * 1024 }) {
-    this.maxSize = maxSize
-    this.maxEntrySize = maxEntrySize
-    this.cache = new Map()
+  constructor() {
+    this.database = null
+    this.init()
   }
 
-  set(key, value, opts) {
-    this.cache.set(key, value)
+  init() {
+    this.database = new DatabaseSync('file:memdb1?mode=memory&cache=shared')
+
+    this.database.exec(`
+      CREATE TABLE IF NOT EXISTS cacheInterceptor(
+        key TEXT,
+        data TEXT,
+        vary TEXT,
+        size INTEGER,
+        ttl INTEGER,
+        insertTime INTEGER
+      ) STRICT
+    `)
+  }
+
+  set(key, entry, opts) {
+    if (!this.database) {
+      throw new Error('Database not initialized')
+    }
+
+    entry.data = JSON.stringify(entry.data)
+    entry.vary = JSON.stringify(entry.vary)
+
+    const insert = this.database.prepare(
+      'INSERT INTO cacheInterceptor (key, data, vary, size, ttl, insertTime) VALUES (?, ?, ?, ?, ?, ?)',
+    )
+
+    insert.run(key, entry.data, entry.vary, entry.size, entry.ttl, Date.now())
+
+    this.purge()
   }
 
   get(key) {
-    return this.cache.get(key)
+    if (!this.database) {
+      throw new Error('Database not initialized')
+    }
+    this.purge()
+    const query = this.database.prepare('SELECT * FROM cacheInterceptor WHERE key = ?')
+    const rows = query.all(key)
+    rows.map((i) => {
+      i.data = JSON.parse(i.data)
+      i.vary = JSON.parse(i.vary)
+      return i
+    })
+
+    // Just in case purge hasn't finished
+    const nonExpiredRows = rows.filter((i) => i.insertTime + i.ttl > Date.now())
+
+    return nonExpiredRows
+  }
+
+  purge() {
+    const query = this.database.prepare('DELETE FROM cacheInterceptor WHERE insertTime + ttl < ?')
+    query.run(Date.now())
+  }
+
+  deleteAll() {
+    const query = this.database.prepare('DELETE FROM cacheInterceptor')
+    query.run()
   }
 }
 
@@ -151,12 +200,12 @@ function findEntryByHeaders(entries, reqHeaders) {
   return entries?.find(
     (entry) =>
       entry.vary?.every(([key, val]) => {
-        return reqHeaders[key] === val
+        return reqHeaders?.headers[key] === val
       }) ?? true,
   )
 }
 
-const DEFAULT_CACHE_STORE = new CacheStore({ maxSize: 128 * 1024, maxEntrySize: 1024 })
+const DEFAULT_CACHE_STORE = new CacheStore()
 
 export default (opts) => (dispatch) => (opts, handler) => {
   if (!opts.cache || opts.upgrade) {
@@ -189,14 +238,19 @@ export default (opts) => (dispatch) => (opts, handler) => {
 
   opts.host = opts.host ?? new URL(opts.origin).host
 
+  if (!opts.headers) {
+    opts.headers = {}
+  }
+
+  // idea: use DEFAULT_CACHE_STORE by default if 'cache' not specified, since the cache interceptor was already specified to be used.
   const store = opts.cache === true ? DEFAULT_CACHE_STORE : opts.cache
 
   if (!store) {
     throw new Error(`Cache store not provided.`)
   }
 
   let key = `${opts.method}:${opts.path}`
-  console.log('getting key: ' + key)
+
   let entries = store.get(key)
 
   if (Array.isArray(entries) && entries.length === 0 && opts.method === 'HEAD') {
@@ -219,11 +273,14 @@ export default (opts) => (dispatch) => (opts, handler) => {
     try {
       handler.onConnect(abort)
       signal.throwIfAborted()
+
       handler.onHeaders(statusCode, rawHeaders, resume, statusMessage)
       signal.throwIfAborted()
+
       if (opts.method !== 'HEAD') {
         for (const chunk of body) {
           const ret = handler.onData(chunk)
+
           signal.throwIfAborted()
           if (ret === false) {
             // TODO (fix): back pressure...
@@ -239,8 +296,6 @@ export default (opts) => (dispatch) => (opts, handler) => {
 
     return true
   } else {
-    handler.opts = opts
-    handler.entries = entries
-    return dispatch(opts, new CacheHandler({ handler, store, key }))
+    return dispatch(opts, new CacheHandler({ handler, store, key, opts }))
   }
 }

package.json

@@ -12,7 +12,6 @@
     "cache-control-parser": "^2.0.6",
     "cacheable-lookup": "^7.0.0",
     "http-errors": "^2.0.0",
-    "lru-cache": "^11.0.0",
     "undici": "^6.19.5"
   },
   "devDependencies": {