feat: add body parser limit for server actions (#51104)

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behind a change

### What?
Add configuration options to modify the `bodyParser` size as it used to
be available in Page Router.
### Why?
Server Actions "Error: Body exceeded 1mb limit" cannot be resolved since
the body-parser limit size is hardcoded to `1mb`.
### How?

Closes NEXT-
Fixes #

-->

### What?

Add configuration options to modify the `bodyParser` size as it used to
be available in Page Router for APIs.

```js
export const config = {
  api: {
    responseLimit: false | '8mb' 
  },
}
```

Reference: [API Routes Response Size
Limit](https://nextjs.org/docs/messages/api-routes-response-size-limit)

### Why?

Server Actions "Error: Body exceeded 1mb limit" cannot be resolved since
the body-parser limit size is hardcoded to `1mb`.

```js
// /packages/next/src/server/app-render/action-handler.ts

// ...
const actionData = (await parseBody(req, '1mb')) || ''
// ...
```

Reference:
https://github.com/vercel/next.js/blob/canary/packages/next/src/server/app-render/action-handler.ts#L355
### How?

- Added option "serverActionsLimit" as `SizeLimit` type to
`config-shared.ts`
- Modified `action-handler.ts` to validate `serverActions` &
`serverActionsLimit` options in nextConfig
- Added conditional `serverActionsLimit` value and `1mb` if falsy

**Working on testing**

Fixes #49891 | #51097 | #51099

---------

Co-authored-by: JJ Kasper <jj@jjsweb.site>
Co-authored-by: Shu Ding <g@shud.in>

packages/next/src/build/entries.ts

@@ -377,6 +377,7 @@ export function getEdgeServerEntry(opts: {
     middlewareConfig: Buffer.from(
       JSON.stringify(opts.middlewareConfig || {})
     ).toString('base64'),
+    serverActionsSizeLimit: opts.config.experimental.serverActionsSizeLimit,
   }
 
   return {

packages/next/src/build/webpack-config.ts

@@ -773,8 +773,8 @@ export default async function getBaseWebpackConfig(
   const hasServerComponents = hasAppDir
   const disableOptimizedLoading = true
   const enableTypedRoutes = !!config.experimental.typedRoutes && hasAppDir
-  const serverActions = !!config.experimental.serverActions && hasAppDir
-  const bundledReactChannel = serverActions ? '-experimental' : ''
+  const useServerActions = !!config.experimental.serverActions && hasAppDir
+  const bundledReactChannel = useServerActions ? '-experimental' : ''
 
   if (isClient) {
     if (
@@ -2418,7 +2418,7 @@ export default async function getBaseWebpackConfig(
               appDir,
               dev,
               isEdgeServer,
-              useServerActions: serverActions,
+              useServerActions,
             })),
       hasAppDir &&
         !isClient &&

packages/next/src/build/webpack/loaders/next-edge-ssr-loader/index.ts

@@ -1,4 +1,6 @@
 import type webpack from 'webpack'
+import type { SizeLimit } from '../../../../../types'
+
 import { getModuleBuildInfo } from '../get-module-build-info'
 import { WEBPACK_RESOURCE_QUERIES } from '../../../../lib/constants'
 import { stringifyRequest } from '../../stringify-request'
@@ -21,6 +23,7 @@ export type EdgeSSRLoaderQuery = {
   incrementalCacheHandlerPath?: string
   preferredRegion: string | string[] | undefined
   middlewareConfig: string
+  serverActionsSizeLimit?: SizeLimit
 }
 
 /*
@@ -54,6 +57,7 @@ const edgeSSRLoader: webpack.LoaderDefinitionFunction<EdgeSSRLoaderQuery> =
       incrementalCacheHandlerPath,
       preferredRegion,
       middlewareConfig: middlewareConfigBase64,
+      serverActionsSizeLimit,
     } = this.getOptions()
 
     const middlewareConfig: MiddlewareConfig = JSON.parse(
@@ -173,6 +177,11 @@ const edgeSSRLoader: webpack.LoaderDefinitionFunction<EdgeSSRLoaderQuery> =
       reactLoadableManifest,
       clientReferenceManifest: ${isServerComponent} ? rscManifest : null,
       serverActionsManifest: ${isServerComponent} ? rscServerManifest : null,
+      serverActionsSizeLimit: ${isServerComponent} ? ${
+      typeof serverActionsSizeLimit === 'undefined'
+        ? 'undefined'
+        : JSON.stringify(serverActionsSizeLimit)
+    } : undefined,
       subresourceIntegrityManifest,
       config: ${stringifiedConfig},
       buildId: ${JSON.stringify(buildId)},

packages/next/src/build/webpack/loaders/next-edge-ssr-loader/render.ts

@@ -14,6 +14,7 @@ import {
 import { SERVER_RUNTIME } from '../../../../lib/constants'
 import { PrerenderManifest } from '../../..'
 import { normalizeAppPath } from '../../../../shared/lib/router/utils/app-paths'
+import { SizeLimit } from '../../../../../types'
 
 export function getRender({
   dev,
@@ -31,6 +32,7 @@ export function getRender({
   clientReferenceManifest,
   subresourceIntegrityManifest,
   serverActionsManifest,
+  serverActionsSizeLimit,
   config,
   buildId,
   nextFontManifest,
@@ -51,6 +53,7 @@ export function getRender({
   subresourceIntegrityManifest?: Record<string, string>
   clientReferenceManifest?: ClientReferenceManifest
   serverActionsManifest: any
+  serverActionsSizeLimit?: SizeLimit
   appServerMod: any
   config: NextConfigComplete
   buildId: string
@@ -85,6 +88,7 @@ export function getRender({
         disableOptimizedLoading: true,
         clientReferenceManifest,
         serverActionsManifest,
+        serverActionsSizeLimit,
       },
       renderToHTML,
       incrementalCacheHandler,

packages/next/src/build/webpack/plugins/flight-client-entry-plugin.ts

@@ -30,12 +30,14 @@ import {
 import { traverseModules, forEachEntryModule } from '../utils'
 import { normalizePathSep } from '../../../shared/lib/page-path/normalize-path-sep'
 import { getProxiedPluginState } from '../../build-context'
+import { SizeLimit } from '../../../../types'
 
 interface Options {
   dev: boolean
   appDir: string
   isEdgeServer: boolean
   useServerActions: boolean
+  serverActionsSizeLimit?: SizeLimit
 }
 
 const PLUGIN_NAME = 'ClientEntryPlugin'
@@ -151,13 +153,15 @@ export class ClientReferenceEntryPlugin {
   appDir: string
   isEdgeServer: boolean
   useServerActions: boolean
+  serverActionsSizeLimit?: SizeLimit
   assetPrefix: string
 
   constructor(options: Options) {
     this.dev = options.dev
     this.appDir = options.appDir
     this.isEdgeServer = options.isEdgeServer
     this.useServerActions = options.useServerActions
+    this.serverActionsSizeLimit = options.serverActionsSizeLimit
     this.assetPrefix = !this.dev && !this.isEdgeServer ? '../' : ''
   }
 

packages/next/src/export/index.ts

@@ -472,6 +472,7 @@ export default async function exportApp(
       largePageDataBytes: nextConfig.experimental.largePageDataBytes,
       serverComponents: options.hasAppDir,
       hasServerComponents: options.hasAppDir,
+      serverActionsSizeLimit: nextConfig.experimental.serverActionsSizeLimit,
       nextFontManifest: require(join(
         distDir,
         'server',

packages/next/src/server/app-render/action-handler.ts

@@ -5,6 +5,7 @@ import type {
   ServerResponse,
 } from 'http'
 import type { WebNextRequest } from '../base-http/web'
+import type { SizeLimit } from '../../../types'
 
 import {
   ACTION,
@@ -245,6 +246,7 @@ export async function handleAction({
   generateFlight,
   staticGenerationStore,
   requestStore,
+  serverActionsSizeLimit,
 }: {
   req: IncomingMessage
   res: ServerResponse
@@ -258,6 +260,7 @@ export async function handleAction({
   }) => Promise<RenderResult>
   staticGenerationStore: StaticGenerationStore
   requestStore: RequestStore
+  serverActionsSizeLimit?: SizeLimit
 }): Promise<undefined | RenderResult | 'not-found'> {
   let actionId = req.headers[ACTION.toLowerCase()] as string
   const contentType = req.headers['content-type']
@@ -372,7 +375,9 @@ export async function handleAction({
           } else {
             const { parseBody } =
               require('../api-utils/node') as typeof import('../api-utils/node')
-            const actionData = (await parseBody(req, '1mb')) || ''
+
+            const actionData =
+              (await parseBody(req, serverActionsSizeLimit ?? '1mb')) || ''
 
             if (isURLEncodedAction) {
               const formData = formDataFromSearchQueryString(actionData)

packages/next/src/server/app-render/app-render.tsx

@@ -156,6 +156,7 @@ export async function renderToHTMLOrFlight(
     nextFontManifest,
     supportsDynamicHTML,
     nextConfigOutput,
+    serverActionsSizeLimit,
   } = renderOpts
 
   const appUsingSizeAdjust = nextFontManifest?.appUsingSizeAdjust
@@ -1606,6 +1607,7 @@ export async function renderToHTMLOrFlight(
       generateFlight,
       staticGenerationStore,
       requestStore,
+      serverActionsSizeLimit,
     })
 
     if (actionRequestResult === 'not-found') {

packages/next/src/server/app-render/types.ts

@@ -1,5 +1,6 @@
 import type { LoadComponentsReturnType } from '../load-components'
-import type { ServerRuntime } from '../../../types'
+import type { ServerRuntime, SizeLimit } from '../../../types'
+import { NextConfigComplete } from '../../server/config-shared'
 import type { ClientReferenceManifest } from '../../build/webpack/plugins/flight-manifest-plugin'
 import type { NextFontManifest } from '../../build/webpack/plugins/next-font-manifest-plugin'
 
@@ -138,6 +139,14 @@ export type RenderOptsPartial = {
   originalPathname?: string
   isDraftMode?: boolean
   deploymentId?: string
+  loadConfig?: (
+    phase: string,
+    dir: string,
+    customConfig?: object | null,
+    rawConfig?: boolean,
+    silent?: boolean
+  ) => Promise<NextConfigComplete>
+  serverActionsSizeLimit?: SizeLimit
 }
 
 export type RenderOpts = LoadComponentsReturnType & RenderOptsPartial

packages/next/src/server/base-server.ts

@@ -19,7 +19,7 @@ import {
   normalizeRepeatedSlashes,
   MissingStaticPage,
 } from '../shared/lib/utils'
-import type { PreviewData, ServerRuntime } from 'next/types'
+import type { PreviewData, ServerRuntime, SizeLimit } from 'next/types'
 import type { PagesManifest } from '../build/webpack/plugins/pages-manifest-plugin'
 import type { OutgoingHttpHeaders } from 'http2'
 import type { BaseNextRequest, BaseNextResponse } from './base-http'
@@ -255,6 +255,7 @@ export default abstract class Server<ServerOptions extends Options = Options> {
     supportsDynamicHTML?: boolean
     isBot?: boolean
     clientReferenceManifest?: ClientReferenceManifest
+    serverActionsSizeLimit?: SizeLimit
     serverActionsManifest?: any
     nextFontManifest?: NextFontManifest
     renderServerComponentData?: boolean
@@ -1650,6 +1651,8 @@ export default abstract class Server<ServerOptions extends Options = Options> {
               incrementalCache,
               isRevalidate: isSSG,
               originalPathname: components.ComponentMod.originalPathname,
+              serverActionsSizeLimit:
+                this.nextConfig.experimental.serverActionsSizeLimit,
             }
           : {}),
         isDataReq,

packages/next/src/server/config-schema.ts

@@ -304,6 +304,16 @@ const configSchema = {
         serverActions: {
           type: 'boolean',
         },
+        serverActionsSizeLimit: {
+          oneOf: [
+            {
+              type: 'number',
+            },
+            {
+              type: 'string',
+            },
+          ] as any,
+        },
         extensionAlias: {
           type: 'object',
         },

packages/next/src/server/config-shared.ts

@@ -9,6 +9,7 @@ import {
 import { SubresourceIntegrityAlgorithm } from '../build/webpack/plugins/subresource-integrity-plugin'
 import { WEB_VITALS } from '../shared/lib/utils'
 import type { NextParsedUrlQuery } from './request-meta'
+import { SizeLimit } from '../../types'
 
 export type NextConfigComplete = Required<NextConfig> & {
   images: Required<ImageConfigComplete>
@@ -281,6 +282,11 @@ export interface ExperimentalConfig {
    * Enable `react@experimental` channel for the `app` directory.
    */
   serverActions?: boolean
+
+  /**
+   * Allows adjusting body parser size limit for server actions.
+   */
+  serverActionsSizeLimit?: SizeLimit
 }
 
 export type ExportPathMap = {

packages/next/src/server/config.ts

@@ -416,6 +416,17 @@ function assignDefaults(
     result.output = 'standalone'
   }
 
+  if (typeof result.experimental?.serverActionsSizeLimit !== 'undefined') {
+    const value = parseInt(
+      result.experimental.serverActionsSizeLimit.toString()
+    )
+    if (isNaN(value) || value < 1) {
+      throw new Error(
+        'Server Actions Size Limit must be a valid number or filesize format lager than 1MB: https://nextjs.org/docs/app/building-your-application/data-fetching/server-actions'
+      )
+    }
+  }
+
   warnOptionHasBeenMovedOutOfExperimental(
     result,
     'transpilePackages',

packages/next/src/server/render.tsx

@@ -23,6 +23,7 @@ import type {
   GetStaticProps,
   PreviewData,
   ServerRuntime,
+  SizeLimit,
 } from 'next/types'
 import type { UnwrapPromise } from '../lib/coalesced-function'
 import type { ReactReadableStream } from './stream-utils/node-web-streams-helper'
@@ -260,6 +261,7 @@ export type RenderOptsPartial = {
   isBot?: boolean
   runtime?: ServerRuntime
   serverComponents?: boolean
+  serverActionsSizeLimit?: SizeLimit
   customServer?: boolean
   crossOrigin?: 'anonymous' | 'use-credentials' | '' | undefined
   images: ImageConfigComplete