Reduce the size of web server (#34767)

By moving `setRevalidateHeaders` to a separate file we can shake off the dependency of `etag` and a polyfill for `Buffer` from the web server (which brings hundreds of kilobytes).

## Bug

- [ ] Related issues linked using `fixes #number`
- [ ] Integration tests added
- [ ] Errors have helpful link attached, see `contributing.md`

## Feature

- [ ] Implements an existing feature request or RFC. Make sure the feature request has been accepted for implementation before opening a PR.
- [ ] Related issues linked using `fixes #number`
- [ ] Integration tests added
- [ ] Documentation added
- [ ] Telemetry added. In case of a feature if it's used or not.
- [ ] Errors have helpful link attached, see `contributing.md`

## Documentation / Examples

- [ ] Make sure the linting passes by running `yarn lint`

packages/next/server/base-server.ts

@@ -16,6 +16,7 @@ import type { CacheFs } from '../shared/lib/utils'
 import type { PreviewData } from 'next/types'
 import type { PagesManifest } from '../build/webpack/plugins/pages-manifest-plugin'
 import type { BaseNextRequest, BaseNextResponse } from './base-http'
+import type { PayloadOptions } from './send-payload'
 
 import { join, resolve } from 'path'
 import { parse as parseQs } from 'querystring'
@@ -42,7 +43,7 @@ import * as envConfig from '../shared/lib/runtime-config'
 import { DecodeError, normalizeRepeatedSlashes } from '../shared/lib/utils'
 import { isTargetLikeServerless } from './utils'
 import Router, { replaceBasePath, route } from './router'
-import { PayloadOptions, setRevalidateHeaders } from './send-payload'
+import { setRevalidateHeaders } from './send-payload/revalidate-headers'
 import { IncrementalCache } from './incremental-cache'
 import { execOnce } from '../shared/lib/utils'
 import { isBlockedPage, isBot } from './utils'

packages/next/server/send-payload.ts → packages/next/server/send-payload/index.ts

@@ -1,42 +1,17 @@
 import type { IncomingMessage, ServerResponse } from 'http'
-import type { BaseNextResponse } from './base-http'
 
-import { isResSent } from '../shared/lib/utils'
+import { isResSent } from '../../shared/lib/utils'
 import generateETag from 'next/dist/compiled/etag'
 import fresh from 'next/dist/compiled/fresh'
-import RenderResult from './render-result'
+import RenderResult from '../render-result'
+import { setRevalidateHeaders } from './revalidate-headers'
 
 export type PayloadOptions =
   | { private: true }
   | { private: boolean; stateful: true }
   | { private: boolean; stateful: false; revalidate: number | false }
 
-export function setRevalidateHeaders(
-  res: ServerResponse | BaseNextResponse,
-  options: PayloadOptions
-) {
-  if (options.private || options.stateful) {
-    if (options.private || !res.hasHeader('Cache-Control')) {
-      res.setHeader(
-        'Cache-Control',
-        `private, no-cache, no-store, max-age=0, must-revalidate`
-      )
-    }
-  } else if (typeof options.revalidate === 'number') {
-    if (options.revalidate < 1) {
-      throw new Error(
-        `invariant: invalid Cache-Control duration provided: ${options.revalidate} < 1`
-      )
-    }
-
-    res.setHeader(
-      'Cache-Control',
-      `s-maxage=${options.revalidate}, stale-while-revalidate`
-    )
-  } else if (options.revalidate === false) {
-    res.setHeader('Cache-Control', `s-maxage=31536000, stale-while-revalidate`)
-  }
-}
+export { setRevalidateHeaders }
 
 export async function sendRenderResult({
   req,

packages/next/server/send-payload/revalidate-headers.ts

@@ -0,0 +1,30 @@
+import type { ServerResponse } from 'http'
+import type { BaseNextResponse } from '../base-http'
+import type { PayloadOptions } from './index'
+
+export function setRevalidateHeaders(
+  res: ServerResponse | BaseNextResponse,
+  options: PayloadOptions
+) {
+  if (options.private || options.stateful) {
+    if (options.private || !res.hasHeader('Cache-Control')) {
+      res.setHeader(
+        'Cache-Control',
+        `private, no-cache, no-store, max-age=0, must-revalidate`
+      )
+    }
+  } else if (typeof options.revalidate === 'number') {
+    if (options.revalidate < 1) {
+      throw new Error(
+        `invariant: invalid Cache-Control duration provided: ${options.revalidate} < 1`
+      )
+    }
+
+    res.setHeader(
+      'Cache-Control',
+      `s-maxage=${options.revalidate}, stale-while-revalidate`
+    )
+  } else if (options.revalidate === false) {
+    res.setHeader('Cache-Control', `s-maxage=31536000, stale-while-revalidate`)
+  }
+}

test/integration/production-swcminify/test/index.test.js

@@ -75,7 +75,7 @@ describe.skip('Production Usage with swcMinify', () => {
     expect(serverTrace.version).toBe(1)
     expect(
       serverTrace.files.some((file) =>
-        file.includes('next/dist/server/send-payload.js')
+        file.includes('next/dist/server/send-payload/index.js')
       )
     ).toBe(true)
     expect(

test/integration/production/test/index.test.js

@@ -95,7 +95,7 @@ describe('Production Usage', () => {
     expect(serverTrace.version).toBe(1)
     expect(
       serverTrace.files.some((file) =>
-        file.includes('next/dist/server/send-payload.js')
+        file.includes('next/dist/server/send-payload/index.js')
       )
     ).toBe(true)
     expect(