Ensure i18n support with AMP

packages/next/build/index.ts

@@ -795,7 +795,7 @@ export default async function build(
               const outputPath = `/${locale}${page === '/' ? '' : page}`
 
               defaultMap[outputPath] = {
-                page: defaultMap[page].page,
+                page: defaultMap[page]?.page || page,
                 query: { __nextLocale: locale },
               }
 

packages/next/build/webpack/loaders/next-serverless-loader.ts

@@ -533,6 +533,18 @@ const nextServerlessLoader: loader.Loader = function () {
 
         ${handleBasePath}
 
+        // remove ?amp=1 from request URL if rendering for export
+        if (fromExport && parsedUrl.query.amp) {
+          const queryNoAmp = Object.assign({}, origQuery)
+          delete queryNoAmp.amp
+
+          req.url = formatUrl({
+            ...parsedUrl,
+            search: undefined,
+            query: queryNoAmp
+          })
+        }
+
         if (parsedUrl.pathname.match(/_next\\/data/)) {
           const {
             default: getrouteNoAssetPath,

packages/next/export/worker.ts

@@ -70,6 +70,7 @@ interface RenderOpts {
   fontManifest?: FontManifest
   locales?: string[]
   locale?: string
+  defaultLocale?: string
 }
 
 type ComponentModule = ComponentType<{}> & {
@@ -99,8 +100,9 @@ export default async function exportPage({
     const { query: originalQuery = {} } = pathMap
     const { page } = pathMap
     const filePath = normalizePagePath(path)
-    const ampPath = `${filePath}.amp`
     const isDynamic = isDynamicRoute(page)
+    const ampPath = `${filePath}.amp`
+    let renderAmpPath = ampPath
     let query = { ...originalQuery }
     let params: { [key: string]: string | string[] } | undefined
 
@@ -114,6 +116,10 @@ export default async function exportPage({
       if (localePathResult.detectedLocale) {
         updatedPath = localePathResult.pathname
         locale = localePathResult.detectedLocale
+
+        if (locale === renderOpts.defaultLocale) {
+          renderAmpPath = `${normalizePagePath(updatedPath)}.amp`
+        }
       }
     }
 
@@ -238,7 +244,7 @@ export default async function exportPage({
           res,
           'export',
           {
-            ampPath,
+            ampPath: renderAmpPath,
             /// @ts-ignore
             optimizeFonts,
             /// @ts-ignore
@@ -298,7 +304,7 @@ export default async function exportPage({
         curRenderOpts = {
           ...components,
           ...renderOpts,
-          ampPath,
+          ampPath: renderAmpPath,
           params,
           optimizeFonts,
           optimizeImages,
@@ -352,16 +358,23 @@ export default async function exportPage({
         if (serverless) {
           req.url += (req.url!.includes('?') ? '&' : '?') + 'amp=1'
           // @ts-ignore
-          ampHtml = (await renderMethod(req, res, 'export', undefined, params))
-            .html
+          ampHtml = (
+            await (renderMethod as any)(
+              req,
+              res,
+              'export',
+              curRenderOpts,
+              params
+            )
+          ).html
         } else {
           ampHtml = await renderMethod(
             req,
             res,
             page,
             // @ts-ignore
-            { ...query, amp: 1 },
-            curRenderOpts
+            { ...query, amp: '1' },
+            curRenderOpts as any
           )
         }
 

packages/next/next-server/server/next-server.ts

@@ -335,6 +335,7 @@ export default class Server {
           ...parsed,
           pathname: localePathResult.pathname,
         })
+        ;(req as any).__nextStrippedLocale = true
         parsedUrl.pathname = localePathResult.pathname
 
         // check if the locale prefix matches a domain's defaultLocale

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

@@ -899,6 +899,10 @@ export async function renderToHTML(
 
   let html = renderDocument(Document, {
     ...renderOpts,
+    canonicalBase:
+      !renderOpts.ampPath && (req as any).__nextStrippedLocale
+        ? `${renderOpts.canonicalBase || ''}/${renderOpts.locale}`
+        : renderOpts.canonicalBase,
     docComponentsRendered,
     buildManifest: filteredBuildManifest,
     // Only enabled in production as development mode has features relying on HMR (style injection for example)

test/integration/i18n-support/pages/amp/amp-first.js

@@ -0,0 +1,32 @@
+import { useAmp } from 'next/amp'
+import { useRouter } from 'next/router'
+
+export const config = {
+  amp: true,
+}
+
+export default function Page(props) {
+  const router = useRouter()
+
+  return (
+    <>
+      <p id="another">another page</p>
+      <p id="is-amp">{useAmp() ? 'yes' : 'no'}</p>
+      <p id="props">{JSON.stringify(props)}</p>
+      <p id="router-locale">{router.locale}</p>
+      <p id="router-locales">{JSON.stringify(router.locales)}</p>
+      <p id="router-query">{JSON.stringify(router.query)}</p>
+      <p id="router-pathname">{router.pathname}</p>
+      <p id="router-as-path">{router.asPath}</p>
+    </>
+  )
+}
+
+export const getServerSideProps = ({ locale, locales }) => {
+  return {
+    props: {
+      locale,
+      locales,
+    },
+  }
+}

test/integration/i18n-support/pages/amp/amp-hybrid.js

@@ -0,0 +1,23 @@
+import { useAmp } from 'next/amp'
+import { useRouter } from 'next/router'
+
+export const config = {
+  amp: 'hybrid',
+}
+
+export default function Page(props) {
+  const router = useRouter()
+
+  return (
+    <>
+      <p id="another">another page</p>
+      <p id="is-amp">{useAmp() ? 'yes' : 'no'}</p>
+      <p id="props">{JSON.stringify(props)}</p>
+      <p id="router-locale">{router.locale}</p>
+      <p id="router-locales">{JSON.stringify(router.locales)}</p>
+      <p id="router-query">{JSON.stringify(router.query)}</p>
+      <p id="router-pathname">{router.pathname}</p>
+      <p id="router-as-path">{router.asPath}</p>
+    </>
+  )
+}

test/integration/i18n-support/test/index.test.js

@@ -416,6 +416,53 @@ function runTests(isDev) {
     await checkDomainLocales('fr', 'example.fr')
   })
 
+  it('should generate AMP pages with all locales', async () => {
+    for (const locale of locales) {
+      const localePath = locale !== 'en-US' ? `/${locale}` : ''
+      const html = await renderViaHTTP(appPort, `${localePath}/amp/amp-hybrid`)
+      const $ = cheerio.load(html)
+      expect($('html').attr('lang')).toBe(locale)
+      expect($('#is-amp').text()).toBe('no')
+      expect($('#router-locale').text()).toBe(locale)
+      expect(JSON.parse($('#router-locales').text())).toEqual(locales)
+      expect($('#router-pathname').text()).toBe('/amp/amp-hybrid')
+      expect($('#router-as-path').text()).toBe('/amp/amp-hybrid')
+      expect(JSON.parse($('#router-query').text())).toEqual({})
+
+      const amphtmlPath = `${localePath}/amp/amp-hybrid${
+        isDev ? '?amp=1' : '.amp'
+      }`
+      expect($('link[rel=amphtml]').attr('href')).toBe(amphtmlPath)
+
+      const html2 = await renderViaHTTP(appPort, amphtmlPath)
+      const $2 = cheerio.load(html2)
+      expect($2('html').attr('lang')).toBe(locale)
+      expect($2('#is-amp').text()).toBe('yes')
+      expect($2('#router-locale').text()).toBe(locale)
+      expect(JSON.parse($2('#router-locales').text())).toEqual(locales)
+      expect($2('#router-pathname').text()).toBe('/amp/amp-hybrid')
+      expect($2('#router-as-path').text()).toBe('/amp/amp-hybrid')
+      expect(JSON.parse($2('#router-query').text())).toEqual({ amp: '1' })
+      expect($2('link[rel=amphtml]').attr('href')).toBeFalsy()
+    }
+  })
+
+  it('should work with AMP first page with all locales', async () => {
+    for (const locale of locales) {
+      const localePath = locale !== 'en-US' ? `/${locale}` : ''
+      const html = await renderViaHTTP(appPort, `${localePath}/amp/amp-first`)
+      const $ = cheerio.load(html)
+      expect($('html').attr('lang')).toBe(locale)
+      expect($('#is-amp').text()).toBe('yes')
+      expect($('#router-locale').text()).toBe(locale)
+      expect(JSON.parse($('#router-locales').text())).toEqual(locales)
+      expect($('#router-pathname').text()).toBe('/amp/amp-first')
+      expect($('#router-as-path').text()).toBe('/amp/amp-first')
+      expect(JSON.parse($('#router-query').text())).toEqual({})
+      expect($('link[rel=amphtml]').attr('href')).toBeFalsy()
+    }
+  })
+
   it('should generate fallbacks with all locales', async () => {
     for (const locale of locales) {
       const html = await renderViaHTTP(