feat(i18n): apply specific routing logic only to pages (#9091)

8 files changed, 115 insertions, 6 deletions

diff --git a/.changeset/empty-turtles-wave.md b/.changeset/empty-turtles-wave.md
new file mode 100644
index 000000000..3605ca3d6
--- /dev/null
+++ b/.changeset/empty-turtles-wave.md
@@ -0,0 +1,5 @@
+---
+'astro': patch
+---
+
+The `routingStrategy` `prefix-always` should not force its logic to endpoints. This fixes some regression with `astro:assets` and `@astrojs/rss`.
diff --git a/packages/astro/src/core/app/index.ts b/packages/astro/src/core/app/index.ts
index 2d5cd16ed..ec7990119 100644
--- a/packages/astro/src/core/app/index.ts
+++ b/packages/astro/src/core/app/index.ts
@@ -6,7 +6,7 @@ import type {
 	SSRElement,
 	SSRManifest,
 } from '../../@types/astro.js';
-import { createI18nMiddleware } from '../../i18n/middleware.js';
+import { createI18nMiddleware, i18nPipelineHook } from '../../i18n/middleware.js';
 import type { SinglePageBuiltModule } from '../build/types.js';
 import { getSetCookiesFromResponse } from '../cookies/index.js';
 import { consoleLogDestination } from '../logger/console.js';
@@ -179,6 +179,7 @@ export class App {
 				} else {
 					this.#pipeline.setMiddlewareFunction(i18nMiddleware);
 				}
+				this.#pipeline.onBeforeRenderRoute(i18nPipelineHook);
 			} else {
 				if (mod.onRequest) {
 					this.#pipeline.setMiddlewareFunction(mod.onRequest as MiddlewareEndpointHandler);
diff --git a/packages/astro/src/core/build/generate.ts b/packages/astro/src/core/build/generate.ts
index 6d8f51df2..02837cf69 100644
--- a/packages/astro/src/core/build/generate.ts
+++ b/packages/astro/src/core/build/generate.ts
@@ -30,7 +30,7 @@ import {
 	removeLeadingForwardSlash,
 	removeTrailingForwardSlash,
 } from '../../core/path.js';
-import { createI18nMiddleware } from '../../i18n/middleware.js';
+import { createI18nMiddleware, i18nPipelineHook } from '../../i18n/middleware.js';
 import { runHookBuildGenerated } from '../../integrations/index.js';
 import { getOutputDirectory, isServerLikeOutput } from '../../prerender/utils.js';
 import { PAGE_SCRIPT_ID } from '../../vite-plugin-scripts/index.js';
@@ -289,6 +289,7 @@ async function generatePage(
 		} else {
 			pipeline.setMiddlewareFunction(i18nMiddleware);
 		}
+		pipeline.onBeforeRenderRoute(i18nPipelineHook);
 	} else if (onRequest) {
 		pipeline.setMiddlewareFunction(onRequest as MiddlewareEndpointHandler);
 	}
diff --git a/packages/astro/src/core/pipeline.ts b/packages/astro/src/core/pipeline.ts
index 3d33146c6..bd203b437 100644
--- a/packages/astro/src/core/pipeline.ts
+++ b/packages/astro/src/core/pipeline.ts
@@ -15,6 +15,12 @@ type EndpointResultHandler = (
 	result: Response
 ) => Promise<Response> | Response;
 
+type PipelineHooks = {
+	before: PipelineHookFunction[];
+};
+
+export type PipelineHookFunction = (ctx: RenderContext, mod: ComponentInstance | undefined) => void;
+
 /**
  * This is the basic class of a pipeline.
  *
@@ -23,6 +29,9 @@ type EndpointResultHandler = (
 export class Pipeline {
 	env: Environment;
 	#onRequest?: MiddlewareEndpointHandler;
+	#hooks: PipelineHooks = {
+		before: [],
+	};
 	/**
 	 * The handler accepts the *original* `Request` and result returned by the endpoint.
 	 * It must return a `Response`.
@@ -75,6 +84,9 @@ export class Pipeline {
 		renderContext: RenderContext,
 		componentInstance: ComponentInstance | undefined
 	): Promise<Response> {
+		for (const hook of this.#hooks.before) {
+			hook(renderContext, componentInstance);
+		}
 		const result = await this.#tryRenderRoute(
 			renderContext,
 			this.env,
@@ -158,4 +170,12 @@ export class Pipeline {
 				throw new Error(`Couldn't find route of type [${renderContext.route.type}]`);
 		}
 	}
+
+	/**
+	 * Store a function that will be called before starting the rendering phase.
+	 * @param fn
+	 */
+	onBeforeRenderRoute(fn: PipelineHookFunction) {
+		this.#hooks.before.push(fn);
+	}
 }
diff --git a/packages/astro/src/i18n/middleware.ts b/packages/astro/src/i18n/middleware.ts
index 7d94d7967..ff467ecb3 100644
--- a/packages/astro/src/i18n/middleware.ts
+++ b/packages/astro/src/i18n/middleware.ts
@@ -1,5 +1,9 @@
 import { appendForwardSlash, joinPaths } from '@astrojs/internal-helpers/path';
-import type { MiddlewareEndpointHandler, SSRManifest } from '../@types/astro.js';
+import type { MiddlewareEndpointHandler, RouteData, SSRManifest } from '../@types/astro.js';
+import type { RouteInfo } from '../core/app/types.js';
+import type { PipelineHookFunction } from '../core/pipeline.js';
+
+const routeDataSymbol = Symbol.for('astro.routeData');
 
 // Checks if the pathname doesn't have any locale, exception for the defaultLocale, which is ignored on purpose
 function checkIsLocaleFree(pathname: string, locales: string[]): boolean {
@@ -26,9 +30,19 @@ export function createI18nMiddleware(
 			return await next();
 		}
 
-		const { locales, defaultLocale, fallback } = i18n;
-		const url = context.url;
+		const routeData = Reflect.get(context.request, routeDataSymbol);
+		if (routeData) {
+			// If the route we're processing is not a page, then we ignore it
+			if (
+				(routeData as RouteData).type !== 'page' &&
+				(routeData as RouteData).type !== 'fallback'
+			) {
+				return await next();
+			}
+		}
 
+		const url = context.url;
+		const { locales, defaultLocale, fallback } = i18n;
 		const response = await next();
 
 		if (response instanceof Response) {
@@ -83,3 +97,10 @@ export function createI18nMiddleware(
 		return response;
 	};
 }
+
+/**
+ * This pipeline hook attaches a `RouteData` object to the `Request`
+ */
+export const i18nPipelineHook: PipelineHookFunction = (ctx) => {
+	Reflect.set(ctx.request, routeDataSymbol, ctx.route);
+};
diff --git a/packages/astro/src/vite-plugin-astro-server/route.ts b/packages/astro/src/vite-plugin-astro-server/route.ts
index 580ceb0b6..7468f8819 100644
--- a/packages/astro/src/vite-plugin-astro-server/route.ts
+++ b/packages/astro/src/vite-plugin-astro-server/route.ts
@@ -20,7 +20,7 @@ import {
 import { createRequest } from '../core/request.js';
 import { matchAllRoutes } from '../core/routing/index.js';
 import { isPage, resolveIdToUrl } from '../core/util.js';
-import { createI18nMiddleware } from '../i18n/middleware.js';
+import { createI18nMiddleware, i18nPipelineHook } from '../i18n/middleware.js';
 import { getSortedPreloadedMatches } from '../prerender/routing.js';
 import { isServerLikeOutput } from '../prerender/utils.js';
 import { PAGE_SCRIPT_ID } from '../vite-plugin-scripts/index.js';
@@ -289,6 +289,7 @@ export async function handleRoute({
 			} else {
 				pipeline.setMiddlewareFunction(i18Middleware);
 			}
+			pipeline.onBeforeRenderRoute(i18nPipelineHook);
 		} else if (onRequest) {
 			pipeline.setMiddlewareFunction(onRequest);
 		}
diff --git a/packages/astro/test/fixtures/i18n-routing-prefix-always/src/pages/test.json.js b/packages/astro/test/fixtures/i18n-routing-prefix-always/src/pages/test.json.js
new file mode 100644
index 000000000..76f3cd446
--- /dev/null
+++ b/packages/astro/test/fixtures/i18n-routing-prefix-always/src/pages/test.json.js
@@ -0,0 +1,7 @@
+export const GET = () => {
+	return new Response(JSON.stringify({ lorem: 'ipsum' }), {
+		headers: {
+			'content-type': 'application/json',
+		},
+	});
+};
diff --git a/packages/astro/test/i18-routing.test.js b/packages/astro/test/i18-routing.test.js
index d9a96ef6e..a7e8b318d 100644
--- a/packages/astro/test/i18-routing.test.js
+++ b/packages/astro/test/i18-routing.test.js
@@ -992,3 +992,56 @@ describe('[SSR] i18n routing', () => {
 		});
 	});
 });
+
+describe('i18n routing does not break assets and endpoints', () => {
+	describe('assets', () => {
+		/** @type {import('./test-utils').Fixture} */
+		let fixture;
+
+		before(async () => {
+			fixture = await loadFixture({
+				root: './fixtures/core-image-base/',
+				experimental: {
+					i18n: {
+						defaultLocale: 'en',
+						locales: ['en', 'es'],
+					},
+				},
+				base: '/blog',
+			});
+			await fixture.build();
+		});
+
+		it('should render the image', async () => {
+			const html = await fixture.readFile('/index.html');
+			const $ = cheerio.load(html);
+			const src = $('#local img').attr('src');
+			expect(src.length).to.be.greaterThan(0);
+			expect(src.startsWith('/blog')).to.be.true;
+		});
+	});
+
+	describe('endpoint', () => {
+		/** @type {import('./test-utils').Fixture} */
+		let fixture;
+
+		let app;
+
+		before(async () => {
+			fixture = await loadFixture({
+				root: './fixtures/i18n-routing-prefix-always/',
+				output: 'server',
+				adapter: testAdapter(),
+			});
+			await fixture.build();
+			app = await fixture.loadTestAdapterApp();
+		});
+
+		it('should return the expected data', async () => {
+			let request = new Request('http://example.com/new-site/test.json');
+			let response = await app.render(request);
+			expect(response.status).to.equal(200);
+			expect(await response.text()).includes('lorem');
+		});
+	});
+});