1 files changed, 561 insertions, 0 deletions
diff --git a/vanilla/node_modules/undici/lib/handler/cache-handler.js b/vanilla/node_modules/undici/lib/handler/cache-handler.js
new file mode 100644
index 0000000..93a70e8
--- /dev/null
+++ b/vanilla/node_modules/undici/lib/handler/cache-handler.js
@@ -0,0 +1,561 @@
+'use strict'
+
+const util = require('../core/util')
+const {
+  parseCacheControlHeader,
+  parseVaryHeader,
+  isEtagUsable
+} = require('../util/cache')
+const { parseHttpDate } = require('../util/date.js')
+
+function noop () {}
+
+// Status codes that we can use some heuristics on to cache
+const HEURISTICALLY_CACHEABLE_STATUS_CODES = [
+  200, 203, 204, 206, 300, 301, 308, 404, 405, 410, 414, 501
+]
+
+// Status codes which semantic is not handled by the cache
+// https://datatracker.ietf.org/doc/html/rfc9111#section-3
+// This list should not grow beyond 206 unless the RFC is updated
+// by a newer one including more. Please introduce another list if
+// implementing caching of responses with the 'must-understand' directive.
+const NOT_UNDERSTOOD_STATUS_CODES = [
+  206
+]
+
+const MAX_RESPONSE_AGE = 2147483647000
+
+/**
+ * @typedef {import('../../types/dispatcher.d.ts').default.DispatchHandler} DispatchHandler
+ *
+ * @implements {DispatchHandler}
+ */
+class CacheHandler {
+  /**
+   * @type {import('../../types/cache-interceptor.d.ts').default.CacheKey}
+   */
+  #cacheKey
+
+  /**
+   * @type {import('../../types/cache-interceptor.d.ts').default.CacheHandlerOptions['type']}
+   */
+  #cacheType
+
+  /**
+   * @type {number | undefined}
+   */
+  #cacheByDefault
+
+  /**
+   * @type {import('../../types/cache-interceptor.d.ts').default.CacheStore}
+   */
+  #store
+
+  /**
+   * @type {import('../../types/dispatcher.d.ts').default.DispatchHandler}
+   */
+  #handler
+
+  /**
+   * @type {import('node:stream').Writable | undefined}
+   */
+  #writeStream
+
+  /**
+   * @param {import('../../types/cache-interceptor.d.ts').default.CacheHandlerOptions} opts
+   * @param {import('../../types/cache-interceptor.d.ts').default.CacheKey} cacheKey
+   * @param {import('../../types/dispatcher.d.ts').default.DispatchHandler} handler
+   */
+  constructor ({ store, type, cacheByDefault }, cacheKey, handler) {
+    this.#store = store
+    this.#cacheType = type
+    this.#cacheByDefault = cacheByDefault
+    this.#cacheKey = cacheKey
+    this.#handler = handler
+  }
+
+  onRequestStart (controller, context) {
+    this.#writeStream?.destroy()
+    this.#writeStream = undefined
+    this.#handler.onRequestStart?.(controller, context)
+  }
+
+  onRequestUpgrade (controller, statusCode, headers, socket) {
+    this.#handler.onRequestUpgrade?.(controller, statusCode, headers, socket)
+  }
+
+  /**
+   * @param {import('../../types/dispatcher.d.ts').default.DispatchController} controller
+   * @param {number} statusCode
+   * @param {import('../../types/header.d.ts').IncomingHttpHeaders} resHeaders
+   * @param {string} statusMessage
+   */
+  onResponseStart (
+    controller,
+    statusCode,
+    resHeaders,
+    statusMessage
+  ) {
+    const downstreamOnHeaders = () =>
+      this.#handler.onResponseStart?.(
+        controller,
+        statusCode,
+        resHeaders,
+        statusMessage
+      )
+    const handler = this
+
+    if (
+      !util.safeHTTPMethods.includes(this.#cacheKey.method) &&
+      statusCode >= 200 &&
+      statusCode <= 399
+    ) {
+      // Successful response to an unsafe method, delete it from cache
+      //  https://www.rfc-editor.org/rfc/rfc9111.html#name-invalidating-stored-response
+      try {
+        this.#store.delete(this.#cacheKey)?.catch?.(noop)
+      } catch {
+        // Fail silently
+      }
+      return downstreamOnHeaders()
+    }
+
+    const cacheControlHeader = resHeaders['cache-control']
+    const heuristicallyCacheable = resHeaders['last-modified'] && HEURISTICALLY_CACHEABLE_STATUS_CODES.includes(statusCode)
+    if (
+      !cacheControlHeader &&
+      !resHeaders['expires'] &&
+      !heuristicallyCacheable &&
+      !this.#cacheByDefault
+    ) {
+      // Don't have anything to tell us this response is cachable and we're not
+      //  caching by default
+      return downstreamOnHeaders()
+    }
+
+    const cacheControlDirectives = cacheControlHeader ? parseCacheControlHeader(cacheControlHeader) : {}
+    if (!canCacheResponse(this.#cacheType, statusCode, resHeaders, cacheControlDirectives)) {
+      return downstreamOnHeaders()
+    }
+
+    const now = Date.now()
+    const resAge = resHeaders.age ? getAge(resHeaders.age) : undefined
+    if (resAge && resAge >= MAX_RESPONSE_AGE) {
+      // Response considered stale
+      return downstreamOnHeaders()
+    }
+
+    const resDate = typeof resHeaders.date === 'string'
+      ? parseHttpDate(resHeaders.date)
+      : undefined
+
+    const staleAt =
+      determineStaleAt(this.#cacheType, now, resAge, resHeaders, resDate, cacheControlDirectives) ??
+      this.#cacheByDefault
+    if (staleAt === undefined || (resAge && resAge > staleAt)) {
+      return downstreamOnHeaders()
+    }
+
+    const baseTime = resDate ? resDate.getTime() : now
+    const absoluteStaleAt = staleAt + baseTime
+    if (now >= absoluteStaleAt) {
+      // Response is already stale
+      return downstreamOnHeaders()
+    }
+
+    let varyDirectives
+    if (this.#cacheKey.headers && resHeaders.vary) {
+      varyDirectives = parseVaryHeader(resHeaders.vary, this.#cacheKey.headers)
+      if (!varyDirectives) {
+        // Parse error
+        return downstreamOnHeaders()
+      }
+    }
+
+    const deleteAt = determineDeleteAt(baseTime, cacheControlDirectives, absoluteStaleAt)
+    const strippedHeaders = stripNecessaryHeaders(resHeaders, cacheControlDirectives)
+
+    /**
+     * @type {import('../../types/cache-interceptor.d.ts').default.CacheValue}
+     */
+    const value = {
+      statusCode,
+      statusMessage,
+      headers: strippedHeaders,
+      vary: varyDirectives,
+      cacheControlDirectives,
+      cachedAt: resAge ? now - resAge : now,
+      staleAt: absoluteStaleAt,
+      deleteAt
+    }
+
+    // Not modified, re-use the cached value
+    // https://www.rfc-editor.org/rfc/rfc9111.html#name-handling-304-not-modified
+    if (statusCode === 304) {
+      const handle304 = (cachedValue) => {
+        if (!cachedValue) {
+          // Do not create a new cache entry, as a 304 won't have a body - so cannot be cached.
+          return downstreamOnHeaders()
+        }
+
+        // Re-use the cached value: statuscode, statusmessage, headers and body
+        value.statusCode = cachedValue.statusCode
+        value.statusMessage = cachedValue.statusMessage
+        value.etag = cachedValue.etag
+        value.headers = { ...cachedValue.headers, ...strippedHeaders }
+
+        downstreamOnHeaders()
+
+        this.#writeStream = this.#store.createWriteStream(this.#cacheKey, value)
+
+        if (!this.#writeStream || !cachedValue?.body) {
+          return
+        }
+
+        if (typeof cachedValue.body.values === 'function') {
+          const bodyIterator = cachedValue.body.values()
+
+          const streamCachedBody = () => {
+            for (const chunk of bodyIterator) {
+              const full = this.#writeStream.write(chunk) === false
+              this.#handler.onResponseData?.(controller, chunk)
+              // when stream is full stop writing until we get a 'drain' event
+              if (full) {
+                break
+              }
+            }
+          }
+
+          this.#writeStream
+            .on('error', function () {
+              handler.#writeStream = undefined
+              handler.#store.delete(handler.#cacheKey)
+            })
+            .on('drain', () => {
+              streamCachedBody()
+            })
+            .on('close', function () {
+              if (handler.#writeStream === this) {
+                handler.#writeStream = undefined
+              }
+            })
+
+          streamCachedBody()
+        } else if (typeof cachedValue.body.on === 'function') {
+          // Readable stream body (e.g. from async/remote cache stores)
+          cachedValue.body
+            .on('data', (chunk) => {
+              this.#writeStream.write(chunk)
+              this.#handler.onResponseData?.(controller, chunk)
+            })
+            .on('end', () => {
+              this.#writeStream.end()
+            })
+            .on('error', () => {
+              this.#writeStream = undefined
+              this.#store.delete(this.#cacheKey)
+            })
+
+          this.#writeStream
+            .on('error', function () {
+              handler.#writeStream = undefined
+              handler.#store.delete(handler.#cacheKey)
+            })
+            .on('close', function () {
+              if (handler.#writeStream === this) {
+                handler.#writeStream = undefined
+              }
+            })
+        }
+      }
+
+      /**
+       * @type {import('../../types/cache-interceptor.d.ts').default.CacheValue}
+       */
+      const result = this.#store.get(this.#cacheKey)
+      if (result && typeof result.then === 'function') {
+        result.then(handle304)
+      } else {
+        handle304(result)
+      }
+    } else {
+      if (typeof resHeaders.etag === 'string' && isEtagUsable(resHeaders.etag)) {
+        value.etag = resHeaders.etag
+      }
+
+      this.#writeStream = this.#store.createWriteStream(this.#cacheKey, value)
+
+      if (!this.#writeStream) {
+        return downstreamOnHeaders()
+      }
+
+      this.#writeStream
+        .on('drain', () => controller.resume())
+        .on('error', function () {
+          // TODO (fix): Make error somehow observable?
+          handler.#writeStream = undefined
+
+          // Delete the value in case the cache store is holding onto state from
+          //  the call to createWriteStream
+          handler.#store.delete(handler.#cacheKey)
+        })
+        .on('close', function () {
+          if (handler.#writeStream === this) {
+            handler.#writeStream = undefined
+          }
+
+          // TODO (fix): Should we resume even if was paused downstream?
+          controller.resume()
+        })
+
+      downstreamOnHeaders()
+    }
+  }
+
+  onResponseData (controller, chunk) {
+    if (this.#writeStream?.write(chunk) === false) {
+      controller.pause()
+    }
+
+    this.#handler.onResponseData?.(controller, chunk)
+  }
+
+  onResponseEnd (controller, trailers) {
+    this.#writeStream?.end()
+    this.#handler.onResponseEnd?.(controller, trailers)
+  }
+
+  onResponseError (controller, err) {
+    this.#writeStream?.destroy(err)
+    this.#writeStream = undefined
+    this.#handler.onResponseError?.(controller, err)
+  }
+}
+
+/**
+ * @see https://www.rfc-editor.org/rfc/rfc9111.html#name-storing-responses-to-authen
+ *
+ * @param {import('../../types/cache-interceptor.d.ts').default.CacheOptions['type']} cacheType
+ * @param {number} statusCode
+ * @param {import('../../types/header.d.ts').IncomingHttpHeaders} resHeaders
+ * @param {import('../../types/cache-interceptor.d.ts').default.CacheControlDirectives} cacheControlDirectives
+ */
+function canCacheResponse (cacheType, statusCode, resHeaders, cacheControlDirectives) {
+  // Status code must be final and understood.
+  if (statusCode < 200 || NOT_UNDERSTOOD_STATUS_CODES.includes(statusCode)) {
+    return false
+  }
+  // Responses with neither status codes that are heuristically cacheable, nor "explicit enough" caching
+  // directives, are not cacheable. "Explicit enough": see https://www.rfc-editor.org/rfc/rfc9111.html#section-3
+  if (!HEURISTICALLY_CACHEABLE_STATUS_CODES.includes(statusCode) && !resHeaders['expires'] &&
+    !cacheControlDirectives.public &&
+    cacheControlDirectives['max-age'] === undefined &&
+    // RFC 9111: a private response directive, if the cache is not shared
+    !(cacheControlDirectives.private && cacheType === 'private') &&
+    !(cacheControlDirectives['s-maxage'] !== undefined && cacheType === 'shared')
+  ) {
+    return false
+  }
+
+  if (cacheControlDirectives['no-store']) {
+    return false
+  }
+
+  if (cacheType === 'shared' && cacheControlDirectives.private === true) {
+    return false
+  }
+
+  // https://www.rfc-editor.org/rfc/rfc9111.html#section-4.1-5
+  if (resHeaders.vary?.includes('*')) {
+    return false
+  }
+
+  // https://www.rfc-editor.org/rfc/rfc9111.html#name-storing-responses-to-authen
+  if (resHeaders.authorization) {
+    if (!cacheControlDirectives.public || typeof resHeaders.authorization !== 'string') {
+      return false
+    }
+
+    if (
+      Array.isArray(cacheControlDirectives['no-cache']) &&
+      cacheControlDirectives['no-cache'].includes('authorization')
+    ) {
+      return false
+    }
+
+    if (
+      Array.isArray(cacheControlDirectives['private']) &&
+      cacheControlDirectives['private'].includes('authorization')
+    ) {
+      return false
+    }
+  }
+
+  return true
+}
+
+/**
+ * @param {string | string[]} ageHeader
+ * @returns {number | undefined}
+ */
+function getAge (ageHeader) {
+  const age = parseInt(Array.isArray(ageHeader) ? ageHeader[0] : ageHeader)
+
+  return isNaN(age) ? undefined : age * 1000
+}
+
+/**
+ * @param {import('../../types/cache-interceptor.d.ts').default.CacheOptions['type']} cacheType
+ * @param {number} now
+ * @param {number | undefined} age
+ * @param {import('../../types/header.d.ts').IncomingHttpHeaders} resHeaders
+ * @param {Date | undefined} responseDate
+ * @param {import('../../types/cache-interceptor.d.ts').default.CacheControlDirectives} cacheControlDirectives
+ *
+ * @returns {number | undefined} time that the value is stale at in seconds or undefined if it shouldn't be cached
+ */
+function determineStaleAt (cacheType, now, age, resHeaders, responseDate, cacheControlDirectives) {
+  if (cacheType === 'shared') {
+    // Prioritize s-maxage since we're a shared cache
+    //  s-maxage > max-age > Expire
+    //  https://www.rfc-editor.org/rfc/rfc9111.html#section-5.2.2.10-3
+    const sMaxAge = cacheControlDirectives['s-maxage']
+    if (sMaxAge !== undefined) {
+      return sMaxAge > 0 ? sMaxAge * 1000 : undefined
+    }
+  }
+
+  const maxAge = cacheControlDirectives['max-age']
+  if (maxAge !== undefined) {
+    return maxAge > 0 ? maxAge * 1000 : undefined
+  }
+
+  if (typeof resHeaders.expires === 'string') {
+    // https://www.rfc-editor.org/rfc/rfc9111.html#section-5.3
+    const expiresDate = parseHttpDate(resHeaders.expires)
+    if (expiresDate) {
+      if (now >= expiresDate.getTime()) {
+        return undefined
+      }
+
+      if (responseDate) {
+        if (responseDate >= expiresDate) {
+          return undefined
+        }
+
+        if (age !== undefined && age > (expiresDate - responseDate)) {
+          return undefined
+        }
+      }
+
+      return expiresDate.getTime() - now
+    }
+  }
+
+  if (typeof resHeaders['last-modified'] === 'string') {
+    // https://www.rfc-editor.org/rfc/rfc9111.html#name-calculating-heuristic-fresh
+    const lastModified = new Date(resHeaders['last-modified'])
+    if (isValidDate(lastModified)) {
+      if (lastModified.getTime() >= now) {
+        return undefined
+      }
+
+      const responseAge = now - lastModified.getTime()
+
+      return responseAge * 0.1
+    }
+  }
+
+  if (cacheControlDirectives.immutable) {
+    // https://www.rfc-editor.org/rfc/rfc8246.html#section-2.2
+    return 31536000
+  }
+
+  return undefined
+}
+
+/**
+ * @param {number} now
+ * @param {import('../../types/cache-interceptor.d.ts').default.CacheControlDirectives} cacheControlDirectives
+ * @param {number} staleAt
+ */
+function determineDeleteAt (now, cacheControlDirectives, staleAt) {
+  let staleWhileRevalidate = -Infinity
+  let staleIfError = -Infinity
+  let immutable = -Infinity
+
+  if (cacheControlDirectives['stale-while-revalidate']) {
+    staleWhileRevalidate = staleAt + (cacheControlDirectives['stale-while-revalidate'] * 1000)
+  }
+
+  if (cacheControlDirectives['stale-if-error']) {
+    staleIfError = staleAt + (cacheControlDirectives['stale-if-error'] * 1000)
+  }
+
+  if (staleWhileRevalidate === -Infinity && staleIfError === -Infinity) {
+    immutable = now + 31536000000
+  }
+
+  return Math.max(staleAt, staleWhileRevalidate, staleIfError, immutable)
+}
+
+/**
+ * Strips headers required to be removed in cached responses
+ * @param {import('../../types/header.d.ts').IncomingHttpHeaders} resHeaders
+ * @param {import('../../types/cache-interceptor.d.ts').default.CacheControlDirectives} cacheControlDirectives
+ * @returns {Record<string, string | string []>}
+ */
+function stripNecessaryHeaders (resHeaders, cacheControlDirectives) {
+  const headersToRemove = [
+    'connection',
+    'proxy-authenticate',
+    'proxy-authentication-info',
+    'proxy-authorization',
+    'proxy-connection',
+    'te',
+    'transfer-encoding',
+    'upgrade',
+    // We'll add age back when serving it
+    'age'
+  ]
+
+  if (resHeaders['connection']) {
+    if (Array.isArray(resHeaders['connection'])) {
+      // connection: a
+      // connection: b
+      headersToRemove.push(...resHeaders['connection'].map(header => header.trim()))
+    } else {
+      // connection: a, b
+      headersToRemove.push(...resHeaders['connection'].split(',').map(header => header.trim()))
+    }
+  }
+
+  if (Array.isArray(cacheControlDirectives['no-cache'])) {
+    headersToRemove.push(...cacheControlDirectives['no-cache'])
+  }
+
+  if (Array.isArray(cacheControlDirectives['private'])) {
+    headersToRemove.push(...cacheControlDirectives['private'])
+  }
+
+  let strippedHeaders
+  for (const headerName of headersToRemove) {
+    if (resHeaders[headerName]) {
+      strippedHeaders ??= { ...resHeaders }
+      delete strippedHeaders[headerName]
+    }
+  }
+
+  return strippedHeaders ?? resHeaders
+}
+
+/**
+ * @param {Date} date
+ * @returns {boolean}
+ */
+function isValidDate (date) {
+  return date instanceof Date && Number.isFinite(date.valueOf())
+}
+
+module.exports = CacheHandler