feat(i18n): fallback system in SSG (#8816)

* feat(i18n): fallback system in SSG

* suggestion

packages/astro/src/core/build/buildPipeline.ts

@@ -11,6 +11,8 @@ import { ASTRO_PAGE_RESOLVED_MODULE_ID } from './plugins/plugin-pages.js';
 import { RESOLVED_SPLIT_MODULE_ID } from './plugins/plugin-ssr.js';
 import { ASTRO_PAGE_EXTENSION_POST_PATTERN } from './plugins/util.js';
 import type { PageBuildData, StaticBuildOptions } from './types.js';
+import { routeIsFallback, routeIsRedirect } from '../redirects/helpers.js';
+import { i18nHasFallback } from './util.js';
 
 /**
  * This pipeline is responsible to gather the files emitted by the SSR build and generate the pages by executing these files.
@@ -154,11 +156,17 @@ export class BuildPipeline extends Pipeline {
 				pages.set(pageData, filePath);
 			}
 		}
-		for (const [path, pageData] of this.#internals.pagesByComponent.entries()) {
-			if (pageData.route.type === 'redirect') {
-				pages.set(pageData, path);
+
+		for (const [path, pageDataList] of this.#internals.pagesByComponents.entries()) {
+			for (const pageData of pageDataList) {
+				if (routeIsRedirect(pageData.route)) {
+					pages.set(pageData, path);
+				} else if (routeIsFallback(pageData.route) && i18nHasFallback(this.getConfig())) {
+					pages.set(pageData, path);
+				}
 			}
 		}
+
 		return pages;
 	}
 

packages/astro/src/core/build/generate.ts

@@ -32,7 +32,11 @@ import { runHookBuildGenerated } from '../../integrations/index.js';
 import { getOutputDirectory, isServerLikeOutput } from '../../prerender/utils.js';
 import { PAGE_SCRIPT_ID } from '../../vite-plugin-scripts/index.js';
 import { AstroError, AstroErrorData } from '../errors/index.js';
-import { RedirectSinglePageBuiltModule, getRedirectLocationOrThrow } from '../redirects/index.js';
+import {
+	RedirectSinglePageBuiltModule,
+	getRedirectLocationOrThrow,
+	routeIsRedirect,
+} from '../redirects/index.js';
 import { createRenderContext } from '../render/index.js';
 import { callGetStaticPaths } from '../render/route-cache.js';
 import {
@@ -58,6 +62,9 @@ import type {
 	StylesheetAsset,
 } from './types.js';
 import { getTimeStat, shouldAppendForwardSlash } from './util.js';
+import { createI18nMiddleware } from '../../i18n/middleware.js';
+import { sequence } from '../middleware/index.js';
+import { routeIsFallback } from '../redirects/helpers.js';
 
 function createEntryURL(filePath: string, outFolder: URL) {
 	return new URL('./' + filePath + `?time=${Date.now()}`, outFolder);
@@ -83,6 +90,26 @@ async function getEntryForRedirectRoute(
 	return RedirectSinglePageBuiltModule;
 }
 
+async function getEntryForFallbackRoute(
+	route: RouteData,
+	internals: BuildInternals,
+	outFolder: URL
+): Promise<SinglePageBuiltModule> {
+	if (route.type !== 'fallback') {
+		throw new Error(`Expected a redirect route.`);
+	}
+	if (route.redirectRoute) {
+		const filePath = getEntryFilePathFromComponentPath(internals, route.redirectRoute.component);
+		if (filePath) {
+			const url = createEntryURL(filePath, outFolder);
+			const ssrEntryPage: SinglePageBuiltModule = await import(url.toString());
+			return ssrEntryPage;
+		}
+	}
+
+	return RedirectSinglePageBuiltModule;
+}
+
 function shouldSkipDraft(pageModule: ComponentInstance, settings: AstroSettings): boolean {
 	return (
 		// Drafts are disabled
@@ -176,16 +203,15 @@ export async function generatePages(opts: StaticBuildOptions, internals: BuildIn
 					await generatePage(pageData, ssrEntry, builtPaths, pipeline);
 				}
 			}
-			if (pageData.route.type === 'redirect') {
-				const entry = await getEntryForRedirectRoute(pageData.route, internals, outFolder);
-				await generatePage(pageData, entry, builtPaths, pipeline);
-			}
 		}
 	} else {
 		for (const [pageData, filePath] of pagesToGenerate) {
-			if (pageData.route.type === 'redirect') {
+			if (routeIsRedirect(pageData.route)) {
 				const entry = await getEntryForRedirectRoute(pageData.route, internals, outFolder);
 				await generatePage(pageData, entry, builtPaths, pipeline);
+			} else if (routeIsFallback(pageData.route)) {
+				const entry = await getEntryForFallbackRoute(pageData.route, internals, outFolder);
+				await generatePage(pageData, entry, builtPaths, pipeline);
 			} else {
 				const ssrEntryURLPage = createEntryURL(filePath, outFolder);
 				const entry: SinglePageBuiltModule = await import(ssrEntryURLPage.toString());
@@ -257,6 +283,7 @@ async function generatePage(
 ) {
 	let timeStart = performance.now();
 	const logger = pipeline.getLogger();
+	const config = pipeline.getConfig();
 	const pageInfo = getPageDataByComponent(pipeline.getInternals(), pageData.route.component);
 
 	// may be used in the future for handling rel=modulepreload, rel=icon, rel=manifest etc.
@@ -269,7 +296,16 @@ async function generatePage(
 
 	const pageModulePromise = ssrEntry.page;
 	const onRequest = ssrEntry.onRequest;
-	if (onRequest) {
+	const i18nMiddleware = createI18nMiddleware(config, logger);
+	if (config.experimental.i18n && i18nMiddleware) {
+		if (onRequest) {
+			pipeline.setMiddlewareFunction(
+				sequence(i18nMiddleware, onRequest as MiddlewareEndpointHandler)
+			);
+		} else {
+			pipeline.setMiddlewareFunction(i18nMiddleware);
+		}
+	} else if (onRequest) {
 		pipeline.setMiddlewareFunction(onRequest as MiddlewareEndpointHandler);
 	}
 	if (!pageModulePromise) {
@@ -297,7 +333,9 @@ async function generatePage(
 	};
 
 	const icon =
-		pageData.route.type === 'page' || pageData.route.type === 'redirect'
+		pageData.route.type === 'page' ||
+		pageData.route.type === 'redirect' ||
+		pageData.route.type === 'fallback'
 			? green('▶')
 			: magenta('λ');
 	if (isRelativePath(pageData.route.component)) {

packages/astro/src/core/build/index.ts

@@ -198,7 +198,9 @@ class AstroBuilder {
 		await runHookBuildDone({
 			config: this.settings.config,
 			pages: pageNames,
-			routes: Object.values(allPages).map((pd) => pd.route),
+			routes: Object.values(allPages)
+				.flat()
+				.map((pageData) => pageData.route),
 			logging: this.logger,
 		});
 

packages/astro/src/core/build/internal.ts

@@ -9,7 +9,8 @@ import {
 } from './plugins/plugin-pages.js';
 import { RESOLVED_SPLIT_MODULE_ID } from './plugins/plugin-ssr.js';
 import { ASTRO_PAGE_EXTENSION_POST_PATTERN } from './plugins/util.js';
-import type { PageBuildData, StylesheetAsset, ViteID } from './types.js';
+import type { AllPagesData, PageBuildData, StylesheetAsset, ViteID } from './types.js';
+import { routeIsFallback } from '../redirects/helpers.js';
 
 export interface BuildInternals {
 	/**
@@ -37,9 +38,16 @@ export interface BuildInternals {
 
 	/**
 	 * A map for page-specific information.
+	 * // TODO: Remove in Astro 4.0
+	 * @deprecated
 	 */
 	pagesByComponent: Map<string, PageBuildData>;
 
+	/**
+	 * TODO: Use this in Astro 4.0
+	 */
+	pagesByComponents: Map<string, PageBuildData[]>;
+
 	/**
 	 * A map for page-specific output.
 	 */
@@ -112,6 +120,7 @@ export function createBuildInternals(): BuildInternals {
 		entrySpecifierToBundleMap: new Map<string, string>(),
 		pageToBundleMap: new Map<string, string>(),
 		pagesByComponent: new Map(),
+		pagesByComponents: new Map(),
 		pageOptionsByPage: new Map(),
 		pagesByViteID: new Map(),
 		pagesByClientOnly: new Map(),
@@ -134,7 +143,16 @@ export function trackPageData(
 	componentURL: URL
 ): void {
 	pageData.moduleSpecifier = componentModuleId;
-	internals.pagesByComponent.set(component, pageData);
+	if (!routeIsFallback(pageData.route)) {
+		internals.pagesByComponent.set(component, pageData);
+	}
+	const list = internals.pagesByComponents.get(component);
+	if (list) {
+		list.push(pageData);
+		internals.pagesByComponents.set(component, list);
+	} else {
+		internals.pagesByComponents.set(component, [pageData]);
+	}
 	internals.pagesByViteID.set(viteID(componentURL), pageData);
 }
 
@@ -230,6 +248,14 @@ export function* eachPageData(internals: BuildInternals) {
 	yield* internals.pagesByComponent.values();
 }
 
+export function* eachPageFromAllPages(allPages: AllPagesData): Generator<[string, PageBuildData]> {
+	for (const [path, list] of Object.entries(allPages)) {
+		for (const pageData of list) {
+			yield [path, pageData];
+		}
+	}
+}
+
 export function* eachPageDataFromEntryPoint(
 	internals: BuildInternals
 ): Generator<[PageBuildData, string]> {

packages/astro/src/core/build/page-data.ts

@@ -47,15 +47,29 @@ export async function collectPagesData(
 				clearInterval(routeCollectionLogTimeout);
 			}, 10000);
 			builtPaths.add(route.pathname);
-			allPages[route.component] = {
-				component: route.component,
-				route,
-				moduleSpecifier: '',
-				styles: [],
-				propagatedStyles: new Map(),
-				propagatedScripts: new Map(),
-				hoistedScript: undefined,
-			};
+			if (allPages[route.component]) {
+				allPages[route.component].push({
+					component: route.component,
+					route,
+					moduleSpecifier: '',
+					styles: [],
+					propagatedStyles: new Map(),
+					propagatedScripts: new Map(),
+					hoistedScript: undefined,
+				});
+			} else {
+				allPages[route.component] = [
+					{
+						component: route.component,
+						route,
+						moduleSpecifier: '',
+						styles: [],
+						propagatedStyles: new Map(),
+						propagatedScripts: new Map(),
+						hoistedScript: undefined,
+					},
+				];
+			}
 
 			clearInterval(routeCollectionLogTimeout);
 			if (settings.config.output === 'static') {
@@ -70,18 +84,31 @@ export async function collectPagesData(
 			continue;
 		}
 		// dynamic route:
-		allPages[route.component] = {
-			component: route.component,
-			route,
-			moduleSpecifier: '',
-			styles: [],
-			propagatedStyles: new Map(),
-			propagatedScripts: new Map(),
-			hoistedScript: undefined,
-		};
+		if (allPages[route.component]) {
+			allPages[route.component].push({
+				component: route.component,
+				route,
+				moduleSpecifier: '',
+				styles: [],
+				propagatedStyles: new Map(),
+				propagatedScripts: new Map(),
+				hoistedScript: undefined,
+			});
+		} else {
+			allPages[route.component] = [
+				{
+					component: route.component,
+					route,
+					moduleSpecifier: '',
+					styles: [],
+					propagatedStyles: new Map(),
+					propagatedScripts: new Map(),
+					hoistedScript: undefined,
+				},
+			];
+		}
 	}
 
 	clearInterval(dataCollectionLogTimeout);
-
 	return { assets, allPages };
 }

packages/astro/src/core/build/plugins/plugin-pages.ts

@@ -3,7 +3,7 @@ import type { Plugin as VitePlugin } from 'vite';
 import type { AstroSettings } from '../../../@types/astro.js';
 import { routeIsRedirect } from '../../redirects/index.js';
 import { addRollupInput } from '../add-rollup-input.js';
-import { type BuildInternals } from '../internal.js';
+import { type BuildInternals, eachPageFromAllPages } from '../internal.js';
 import type { AstroBuildPlugin } from '../plugin.js';
 import type { StaticBuildOptions } from '../types.js';
 import { MIDDLEWARE_MODULE_ID } from './plugin-middleware.js';
@@ -42,7 +42,7 @@ function vitePluginPages(opts: StaticBuildOptions, internals: BuildInternals): V
 			if (opts.settings.config.output === 'static') {
 				const inputs = new Set<string>();
 
-				for (const [path, pageData] of Object.entries(opts.allPages)) {
+				for (const [path, pageData] of eachPageFromAllPages(opts.allPages)) {
 					if (routeIsRedirect(pageData.route)) {
 						continue;
 					}

packages/astro/src/core/build/plugins/plugin-ssr.ts

@@ -13,6 +13,7 @@ import { SSR_MANIFEST_VIRTUAL_MODULE_ID } from './plugin-manifest.js';
 import { ASTRO_PAGE_MODULE_ID } from './plugin-pages.js';
 import { RENDERERS_MODULE_ID } from './plugin-renderers.js';
 import { getPathFromVirtualModulePageName, getVirtualModulePageNameFromPath } from './util.js';
+import { eachPageFromAllPages } from '../internal.js';
 
 export const SSR_VIRTUAL_MODULE_ID = '@astrojs-ssr-virtual-entry';
 export const RESOLVED_SSR_VIRTUAL_MODULE_ID = '\0' + SSR_VIRTUAL_MODULE_ID;
@@ -42,7 +43,7 @@ function vitePluginSSR(
 				let i = 0;
 				const pageMap: string[] = [];
 
-				for (const [path, pageData] of Object.entries(allPages)) {
+				for (const [path, pageData] of eachPageFromAllPages(allPages)) {
 					if (routeIsRedirect(pageData.route)) {
 						continue;
 					}
@@ -148,7 +149,7 @@ function vitePluginSSRSplit(
 			if (options.settings.config.build.split || functionPerRouteEnabled) {
 				const inputs = new Set<string>();
 
-				for (const [path, pageData] of Object.entries(options.allPages)) {
+				for (const [path, pageData] of eachPageFromAllPages(options.allPages)) {
 					if (routeIsRedirect(pageData.route)) {
 						continue;
 					}
@@ -294,7 +295,7 @@ function storeEntryPoint(
 	fileName: string
 ) {
 	const componentPath = getPathFromVirtualModulePageName(RESOLVED_SPLIT_MODULE_ID, moduleKey);
-	for (const [page, pageData] of Object.entries(options.allPages)) {
+	for (const [page, pageData] of eachPageFromAllPages(options.allPages)) {
 		if (componentPath == page) {
 			const publicPath = fileURLToPath(options.settings.config.build.server);
 			internals.entryPoints.set(pageData.route, pathToFileURL(join(publicPath, fileName)));