Optimize non-dynamic metadata routes to static in production build

packages/next/src/build/analysis/get-page-static-info.ts

@@ -83,13 +83,23 @@ function checkExports(swcAST: any): {
   ssg: boolean
   runtime?: string
   preferredRegion?: string | string[]
+  generateImageMetadata?: boolean
+  generateSitemaps?: boolean
 } {
+  const exportsSet = new Set<string>([
+    'getStaticProps',
+    'getServerSideProps',
+    'generateImageMetadata',
+    'generateSitemaps',
+  ])
   if (Array.isArray(swcAST?.body)) {
     try {
       let runtime: string | undefined
       let preferredRegion: string | string[] | undefined
       let ssr: boolean = false
       let ssg: boolean = false
+      let generateImageMetadata: boolean = false
+      let generateSitemaps: boolean = false
 
       for (const node of swcAST.body) {
         if (
@@ -122,22 +132,25 @@ function checkExports(swcAST: any): {
         if (
           node.type === 'ExportDeclaration' &&
           node.declaration?.type === 'FunctionDeclaration' &&
-          ['getStaticProps', 'getServerSideProps'].includes(
-            node.declaration.identifier?.value
-          )
+          exportsSet.has(node.declaration.identifier?.value)
         ) {
-          ssg = node.declaration.identifier.value === 'getStaticProps'
-          ssr = node.declaration.identifier.value === 'getServerSideProps'
+          const id = node.declaration.identifier.value
+          ssg = id === 'getStaticProps'
+          ssr = id === 'getServerSideProps'
+          generateImageMetadata = id === 'generateImageMetadata'
+          generateSitemaps = id === 'generateSitemaps'
         }
 
         if (
           node.type === 'ExportDeclaration' &&
           node.declaration?.type === 'VariableDeclaration'
         ) {
           const id = node.declaration?.declarations[0]?.id.value
-          if (['getStaticProps', 'getServerSideProps'].includes(id)) {
+          if (exportsSet.has(id)) {
             ssg = id === 'getStaticProps'
             ssr = id === 'getServerSideProps'
+            generateImageMetadata = id === 'generateImageMetadata'
+            generateSitemaps = id === 'generateSitemaps'
           }
         }
 
@@ -149,18 +162,36 @@ function checkExports(swcAST: any): {
               specifier.orig?.value
           )
 
-          ssg = values.some((value: any) => ['getStaticProps'].includes(value))
-          ssr = values.some((value: any) =>
-            ['getServerSideProps'].includes(value)
-          )
+          for (const value of values) {
+            if (!ssg && value === 'getStaticProps') ssg = true
+            if (!ssr && value === 'getServerSideProps') ssr = true
+            if (!generateImageMetadata && value === 'generateImageMetadata')
+              generateImageMetadata = true
+            if (!generateSitemaps && value === 'generateSitemaps')
+              generateSitemaps = true
+          }
         }
       }
 
-      return { ssr, ssg, runtime, preferredRegion }
+      return {
+        ssr,
+        ssg,
+        runtime,
+        preferredRegion,
+        generateImageMetadata,
+        generateSitemaps,
+      }
     } catch (err) {}
   }
 
-  return { ssg: false, ssr: false }
+  return {
+    ssg: false,
+    ssr: false,
+    runtime: undefined,
+    preferredRegion: undefined,
+    generateImageMetadata: false,
+    generateSitemaps: false,
+  }
 }
 
 async function tryToReadFile(filePath: string, shouldThrow: boolean) {
@@ -329,6 +360,20 @@ function warnAboutUnsupportedValue(
   warnedUnsupportedValueMap.set(pageFilePath, true)
 }
 
+// Detect if metadata routes is a dynamic route, which containing
+// generateImageMetadata or generateSitemaps as export
+export async function isDynamicMetadataRoute(
+  pageFilePath: string
+): Promise<boolean> {
+  const fileContent = (await tryToReadFile(pageFilePath, true)) || ''
+  if (!/generateImageMetadata|generateSitemaps/.test(fileContent)) return false
+
+  const swcAST = await parseModule(pageFilePath, fileContent)
+  const exportsInfo = checkExports(swcAST)
+
+  return !exportsInfo.generateImageMetadata || !exportsInfo.generateSitemaps
+}
+
 /**
  * For a given pageFilePath and nextConfig, if the config supports it, this
  * function will read the file and return the runtime that should be used.

packages/next/src/build/index.ts

@@ -90,8 +90,11 @@ import {
   eventBuildCompleted,
 } from '../telemetry/events'
 import { Telemetry } from '../telemetry/storage'
-import { getPageStaticInfo } from './analysis/get-page-static-info'
-import { createPagesMapping } from './entries'
+import {
+  isDynamicMetadataRoute,
+  getPageStaticInfo,
+} from './analysis/get-page-static-info'
+import { createPagesMapping, getPageFilePath } from './entries'
 import { generateBuildId } from './generate-build-id'
 import { isWriteable } from './is-writeable'
 import * as Log from './output/log'
@@ -462,6 +465,27 @@ export default async function build(
               pagesDir: pagesDir,
             })
           )
+
+        // If the metadata route doesn't contain generating dynamic exports,
+        // we can replace the dynamic catch-all route and use the static route instead.
+        for (const [pageKey, pagePath] of Object.entries(mappedAppPages)) {
+          if (pageKey.includes('[[...__metadata_id__]]')) {
+            const pageFilePath = getPageFilePath({
+              absolutePagePath: pagePath,
+              pagesDir,
+              appDir,
+              rootDir,
+            })
+
+            const isDynamic = await isDynamicMetadataRoute(pageFilePath)
+            if (!isDynamic) {
+              delete mappedAppPages[pageKey]
+              mappedAppPages[pageKey.replace('[[...__metadata_id__]]/', '')] =
+                pagePath
+            }
+          }
+        }
+
         NextBuildContext.mappedAppPages = mappedAppPages
       }
 

packages/next/src/build/webpack/loaders/next-metadata-route-loader.ts

@@ -102,7 +102,7 @@ const handler = imageModule.default
 const generateImageMetadata = imageModule.generateImageMetadata
 
 export async function GET(_, ctx) {
-  const { __metadata_id__ = [], ...params } = ctx.params
+  const { __metadata_id__ = [], ...params } = ctx.params || {}
   const targetId = __metadata_id__[0]
   let id = undefined
   const imageMetadata = generateImageMetadata ? await generateImageMetadata({ params }) : null
@@ -122,7 +122,7 @@ export async function GET(_, ctx) {
       })
     }
   }
-  return handler({ params, id })
+  return handler({ params: ctx.params ? params : undefined, id })
 }
 `
 }
@@ -141,7 +141,7 @@ const contentType = ${JSON.stringify(getContentType(resourcePath))}
 const fileType = ${JSON.stringify(getFilenameAndExtension(resourcePath).name)}
 
 export async function GET(_, ctx) {
-  const { __metadata_id__ = [], ...params } = ctx.params
+  const { __metadata_id__ = [], ...params } = ctx.params || {}
   const targetId = __metadata_id__[0]
   let id = undefined
   const sitemaps = generateSitemaps ? await generateSitemaps() : null

test/e2e/app-dir/metadata-dynamic-routes/index.test.ts

@@ -420,15 +420,31 @@ createNextDescribe(
         const edgeRoute = functionRoutes.find((route) =>
           route.startsWith('/(group)/twitter-image-')
         )
-        expect(edgeRoute).toMatch(
-          /\/\(group\)\/twitter-image-\w{6}\/\[\[\.\.\.__metadata_id__\]\]\/route/
+        expect(edgeRoute).toMatch(/\/\(group\)\/twitter-image-\w{6}\/route/)
+      })
+
+      it('should optimize routes without multiple generation API as static routes', async () => {
+        const appPathsManifest = JSON.parse(
+          await next.readFile('.next/server/app-paths-manifest.json')
         )
+
+        expect(appPathsManifest).toMatchObject({
+          // static routes
+          '/twitter-image/route': 'app/twitter-image/route.js',
+          '/sitemap.xml/route': 'app/sitemap.xml/route.js',
+
+          // dynamic
+          '/(group)/dynamic/[size]/sitemap.xml/[[...__metadata_id__]]/route':
+            'app/(group)/dynamic/[size]/sitemap.xml/[[...__metadata_id__]]/route.js',
+          '/(group)/dynamic/[size]/apple-icon-48jo90/[[...__metadata_id__]]/route':
+            'app/(group)/dynamic/[size]/apple-icon-48jo90/[[...__metadata_id__]]/route.js',
+        })
       })
 
       it('should include default og font files in file trace', async () => {
         const fileTrace = JSON.parse(
           await next.readFile(
-            '.next/server/app/opengraph-image/[[...__metadata_id__]]/route.js.nft.json'
+            '.next/server/app/metadata-base/unset/opengraph-image2/[[...__metadata_id__]]/route.js.nft.json'
           )
         )